Closing in on a problem

[1great40]

Hi Guys, I'm looking for a little help here. I have been dealing with Mark, he made me a new PROM for my 1227747 TBI computer.

I'm running a 4.3 Chevy V6 in my 40 Ford pickup and using a Painless Performance wiring harness. I have had a problem with the idle speed on this engine ever since I got it running. I'm sort of a FI newbie so bear with me.

I decided that an idle speed of 725 RPM would be about right for my engine. It felt smooth at this speed. The original idle was about 630 or so and It loaded down to about 500 in drive. The PROM I got had the idle speed set to 725. I installed the PROM and didn't really notice much of a difference in the idle speed. I hooked up an Actron scanner to the ALDL and started the truck and let it warm up. Sure enough the idle was 725 and it stayed at 725 in gear. Leaving the scanner connected, I drove the truck around a while. I was quite pleased. Later when I disconnected the scanner, the idle was about 725 in park but dropped down to around 500 again in gear.

To make a long story short, Mark had defaulted the idle speed in the diagnostic mode to 725 as well so when the scanner was hooked up, the engine ran at 725. When the engine was not in diagnostic mode, it was not under the control of the computer in drive. The engine was showing IAC counts of 15 at 725 RPM. I checked the Park/neutral switch wiring and the B-10 input to the computer was ground in park and 13.3 volts in drive just as it should be. I verified that the P/N wire did go to the B-10 terminal on the connector and that the connector pins were not bent on the ECU.

My thinking is that the ECU has taken a dump. The only other thing I'm wondering about is the AC request line. Does that have control over the idle? The AC is not yet charged so it will not run.

I don't mind buying another ECU but It would be great to really solve the problem before throwing parts at it. Any input would be appreciated.

[dave w]

I've always been challenged with getting idle speeds set correctly with a vehicle in drive, when the Park / Neutral input (B10) is grounded. With B10 grounded, the ECM thinks the vehicle is always in Park or Neutral. Adding a VSS is not a silver bullet fix all, quite often issues like / similar to the one your are experiencing are often resolved with a VSS. I only recommend grounding B10 for Off Road Only vehicles.

dave w

[1great40]

Thanks Dave. The setup I have is only grounding the B10 input when the vehicle is in park. Once it's out of park, that line is pulled up to battery voltage through an internal pull up resistor in the ECM. That's the way it was done at the factory and that's the way Painless implements it as well in their harness. The truck uses the factory VSS and it feeds a Dakota Digital SGI-5 Universal Signal Interface. I am using the 2000PPM output to fed the ECM. Please explain how the VSS interacts with the idle speed. Maybe I have something wrong with how I wired it.

[dave w]

I don't think you have anything wired wrong. The Painless Wiring Instruction Manual I have, outlines two options for B10, permanently grounded for no emission / no VSS applications or a Park / Neutral switch. I was thinking you had B10 permanently grounded.

I've never measured B10 voltages. The factory wiring diagram shows when the transmission selector switch is in either Park / Neutral ~ ground is applied to B10, otherwise B10 is an open. Measuring an open circuit with a volt meter will typically reflect / show the source voltage.

ECM subroutines, like Deceleration Fuel Cutoff (DFCO) are a function of the VSS input. I don't know enough about the 1227747 code to know all the ECM subroutines related to VSS and idle. For all I know, there could be a timer that is activated when the VSS pulses go to Zero to start a subroutine for Idle.

Maybe you can post a .xdl file and the .bin file your using?

dave w

[Scrufdog]

Is this a B10 problem or do you just need the idle to stick to 725 in drive? Should be a setting for Idle in P/N and Idle in Gear.

[lionelhutz]

I don't believe there are separate park/in-gear idle rpm settings in a 7747 ECM. It uses a single table.

There is a %TPS to enable open loop idle setting. Having the %TPS with the throttle closed above this setting could be keeping the ECM out of closed loop idle control. There is also a speed setting that works the same way but I would have to believe the VSS you're using wouldn't give any speed pulses when you are stopped.

Why does your scanner change the idle rpm? Check what it does when connected. There is a resistor you can connect across a couple of ALDL pins to put the ECM into different troubleshooting modes but that resistor is not needed or desired for a 7747 ECM.

You really need to check that the engine is in closed loop idle control or not. you can even try adjusting the idle screw a small amount. The ECM should compensate by adjusting the IAC motor the opposite way to maintain idle. This works as long as you're within the operating range of the IAC motor.

[ony]

is the 4.3 you have a vortic?

[1great40]

Thank you for the responses. The engine is a basic pre balance shaft, pre Vortec 4.3

Lionel, can you please go into more detail about the %TPS stuff. Please spoon feed me here including explanations of 3 letter acronyms. :)

According to the scanner the engine does attain closed loop operation. The Actron scanner I have access to sets the engine RPM. I don't know why, it just does. That's what fooled me into thinking all was well when I installed the new PROM I got from Mark. He defaulted the diagnostic RPM to 725 as well. Without the scanner attached, even though the PROM is programmed for an idle of 725, I have a hot idle of a little over 600 and it drops to about 500 in drive, so the computer is doing squat to control the idle speed. Is it possible to have the engine operating closed loop but the idle operating open loop?

[ony]

do you have a moniter mode on your scanner? one scaner I have has a diagnoses mode which sets the ecm to were it wants and its got a ok to drive mode that just shows sensor data as you drive.

[1great40]

do you have a moniter mode on your scanner? one scaner I have has a diagnoses mode which sets the ecm to were it wants and its got a ok to drive mode that just shows sensor data as you drive.
I will have to check that out. With the the original prom, connecting the scanner would set the idle to 1000 rpm. With the prom from Mark, connecting the scanner sets the idle to 725. I will have to see if there's a mode that just lets me watch the data and not trick the idle.

[EagleMark]

That Scan tool you are using is always in 10K mode!

[1great40]

That Scan tool you are using is always in 10K mode!


That seems to be the case. The scanner is borrowed so I never really have a lot of time to learn with it. I will probably download the user manual so I can learn more.

[1great40]

I got my hands on the scanner today. The software that comes with it will allow me to print out the data but. I dont know how to save it as anything but a txt file. I'm sorry if I'm being a pest with this but I don't know anyone in my local area who's got the experience with this stuff. This is the 2nd set of data that I took. The first set was with the engine going open loop on me. This is a new condition for me, I had never seen the engine go open loop once it warmed up but dropping it in gear to require more fuel or revving it a bit puts it back into closed loop so now it looks like I have another problem to address although its doubtful it will ever go open loop while idling in drive. Here it is:

Vehicle Data List




CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 10
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.16
O2S(mV) 515
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 107
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:-5 Time:-5.7


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 12
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.06
O2S(mV) 528
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:-4 Time:-4.5


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 12
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 666
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:-3 Time:-3.4


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 12
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 533
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:-2 Time:-2.3


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 12
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 617
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:-1 Time:-1.1


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 524
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 0 Time: 0.0


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 737
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 1 Time: 1.1


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 719
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 2 Time: 2.3


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 493
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 109
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 3 Time: 3.4


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 622
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 4 Time: 4.5


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 697
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 5 Time: 5.7


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 639
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 6 Time: 6.8


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 639
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 7 Time: 7.9


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.06
O2S(mV) 635
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 8 Time: 9.1


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.06
O2S(mV) 591
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame: 9 Time:10.2


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.06
O2S(mV) 537
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:10 Time:11.3


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 599
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:11 Time:12.5


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 733
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 106
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:12 Time:13.6


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 577
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:13 Time:14.7


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 733
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:14 Time:15.9


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 559
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:15 Time:17.0


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 710
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:16 Time:18.1


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 617
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:17 Time:19.3


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 684
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:18 Time:20.4


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 666
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 107
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:19 Time:21.5


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 591
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 104
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:20 Time:22.7


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 608
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:21 Time:23.8


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 679
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:22 Time:24.9


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 591
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:23 Time:26.1


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 604
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:24 Time:27.2


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.5
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.06
O2S(mV) 622
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:25 Time:28.4


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 10
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 648
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:26 Time:29.5


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 10
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 630
O2S CROSSCNTS 75
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:27 Time:30.6


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 12
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 586
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 111
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:28 Time:31.8


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 728
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 109
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:29 Time:32.9


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 10
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.14
O2S(mV) 719
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:30 Time:34.0


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.10
O2S(mV) 591
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 105
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:31 Time:35.2


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.08
O2S(mV) 639
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 102
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:32 Time:36.3


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 750
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.04
O2S(mV) 702
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:33 Time:37.4


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 725
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 10
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.12
O2S(mV) 559
O2S CROSSCNTS 75
P/N SWITCH P/N
PROM ID 103
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:34 Time:38.6


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.7
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 RICH
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.16
O2S(mV) 648
O2S CROSSCNTS 78
P/N SWITCH P/N
PROM ID 109
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
Frame:35 Time:39.7


CODES PRESENT NO
3RD GEAR SW ON
AC REQUEST OFF
AIR DIVRT SOL DIV
AIR SW SOL CONV
BATTERY(V) 13.6
BLM 150
CLEAR FLOOD OFF
COOLANT(øF) 189
ENGINE RPM 700
EXHAUST 02 LEAN
HIGH BATTERY NO
IAC POSITION 11
INTEGRATOR 125
LOOP STATUS CLSD
MAP(V) 1.16
O2S(mV) 715
O2S CROSSCNTS 77
P/N SWITCH P/N
PROM ID 98
TCC LOCKUP NO
TCC SOLENOID OFF
TPS SENSOR(V) 0.43
VEHSPEED(MPH) 0
FRAME: 36

[blue68deville]

It would be worth getting an ALDL cable and downloading tunerpro. It's 100% easier to use and gives you so much more info.
Makes the job of your tuner a lot simpler as well, you'll get a better tune faster.

Very cool truck by the way, I've always loved 40 fords.

[dave w]

It would be worth getting an ALDL cable and downloading tunerpro. It's 100% easier to use and gives you so much more info.
Makes the job of your tuner a lot simpler as well, you'll get a better tune faster.

Very cool truck by the way, I've always loved 40 fords.

What he said x2:thumbsup:

TunerPro RT is a suggested $39 donation.
ALDL cable is usually less than $60.
There is NOT a Scanner Tool sold that can even come close to the information available from a TunerPro RT data log!

dave w

[steveo]

i'd use any scan tool that exports to CSV so you can graph stuff in excel or do math and averaging easily. if you can't do that it's worthless.

failing that, i could (or someone could) write you a script to parse that crap into a workable CSV file too....

[dave w]

I recently helped someone get "Setup" with TurnerPro RT for about $250.

The costs ...
Used Laptop from Best Buy (about $150)http://www.bestbuy.com/site/olstemplatemapper.jsp;jsessionid=08FB412364B2758CA A04A03BEC91BEDA.bbolsp-app02-157?_dyncharset=UTF-8&_dynSessConf=-2057428987692599321&id=pcat17071&type=page&ks=960&st=categoryid%24pcmcat219300050014&sc=Global&cp=1&sp=-bestsellingsort+skuidsaas&qp=currentprice_facet%3DSAAS%7EPrice%7E%24100+-+%24149.99&list=y&usc=All+Categories&nrp=15&fs=saas&iht=n&seeAll=&browsedCategory=pcmcat219300050014

ALDL Cable http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1592-Support-The-Forum-Buy-ALDL-Cables! or http://www.aldlcable.com/products/aldlobd1u.asp

Donation to TunerPro RT ... $39 http://www.tunerpro.net/downloadApp.htm

Open Office (free) https://www.openoffice.org/ (Similar software to Microsoft Office)

dave w

[EagleMark]

Your link to best buy did not work, but I found some laptops that start at $143. so considering refurbished with warrenty that fairly cheap way to get in!

Best Buy Link To Laptops (http://www.bestbuy.com/site/olstemplatemapper.jsp?_dyncharset=UTF-8&_dynSessConf=-40781757174032174&id=pcat17071&type=page&ks=960&st=categoryid%24abcat0500000&sc=Global&cp=1&sp=%2Bcurrentprice+skuidsaas&qp=currentoffers_facet%3DCurrent+Offers~Clearance+ %26+More^category_facet%3DLaptops~abcat0502000^sol dby_facet%3DSAAS~Sold+By~Marketplace+Seller&list=y&usc=All+Categories&nrp=15&fs=saas&iht=n&seeAll=&browsedCategory=pcmcat142300050026)

[1great40]

I have an older Dell laptop that needs a battery, I'm going to order a battery and a cable and download TunerPro. Looks like I'm fixin' to lean me way more than I ever wanted to know about efi.

[1great40]

Can anyone explain what type of influence the VSS has on idle? I always thought that when the vehicle is stopped, there's no input from the VSS. In my case, the VSS is going to a Dakota Digital SGI 5 universal interface and the ECU is supplied with a VSS signal from the interface. Also can anyone explain what closed loop idle is? Is it different than just regular closed loop operation? A previous poster was referring to something about a %TPS before the ECU would go closed loop idle or something like that. I'm confused for sure now! I guess I have a lot of terminology to understand first.

[Scrufdog]

On my 427 ECU, it needs VSS and TPS to set 'idle mode' which uses closed throttle idle and spark maps. If I remember right the TPS needs to be under 2.3% and the VSS needs to be under 3 mph. Closed loop idle means the ECU is using the closed throttle fuel map with the O2 sensor to regulate fuel (using INT and BLM), open loop idle means the ECU is only referencing the fuel map values and not adjusting them.

[1great40]

Ok, It's looking like I'd best go through the minimum air adjustment again since it seems that would effect the %TPS. I'll let you all know how that turns out.

I did set it initially when I got the engine running but it has since been messed with in trying to pick a new idle speed for the engine. I just guessed that since my IAC counts were about 10-15 at idle that I was still OK. The manual from Painless performance just explains the Minimum air adjustment and it tells you to adjust the "idle" speed during this procedure. It's misleading. I recently got a book about Chevrolet Fuel Injection and there's a spec for my engine of 400+25 RPM for the minimum air adjustment RPM.

[EagleMark]

If you have 10-15 IAC counts warmed up after a drive? Leave it alone!

I've read many instructions on how to set Min Air and they are all missing some important part of information. Plus not all chips are same idle RPM, so how can you set it to 425 RPM? Huh? Tell me how that works with an engine that has idle set to 525 RPM... would probably work on that one. But not yours set at 725-750 RPM!

[1great40]

Hi Guys,


Ii h ave been away from working on the truck until a few days ago. I'm in the process of getting an old laptop cleaned up and I'm going to download TunerPro.

I have no response from Robert about the cable so I'm looking elsewhere for one. One thing is for sure...I need to look at my IAC counts when I shift from Park to Drive..From what I can tell there is no control whatsoever on the part of the computer as to where the idle speed is set. I need someone to explain to me the difference between open loop idle and closed loop idle. Also I'm thinking that my minimum air adjustment is off and that may be interfering with the % TPS? I'm hoping to learn a lot by looking at what the engine is doing with TunerPro.

[1great40]

I went through the minimum air setting again tonight. I'm back to using the original stock PROM for the engine. My idle is about 650 RPM in park and it loads down to just under 600 in Drive. I can't tell with my Actron scanner if the IAC counts change when I shift from P to D because I can't get this scanner to operate in anything other than 10K mode I'm calling Actron tomorrow to see if there's any way around that. 10K mode defaults the idle to 1000 RPM so I cant see the counts at normal idle speed.Also, tomorrow I should have that old laptop ready to download TunerPro so even if I cant get a look at the IAC counts with the Actron, I should be able to as soon as I get the software up and running and my cable arrives.

[1great40]

According to Actron, that scanner operates only in the 10K mode. I received my OBD1 ALDL to USB cable yesterday and I have downloaded TunerproRT. Wish me luck :)

[dave w]

According to Actron, that scanner operates only in the 10K mode. I received my OBD1 ALDL to USB cable yesterday and I have downloaded TunerproRT. Wish me luck :)

It's more like homework, no luck needed.

dave w

[1great40]

You're right Dave

[1great40]

Well this is where I really found out how dumb I am. I have downloaded TunerPro RT and I can't get it configured. I have been trying to find out where to get the correct BIN file and the other files needed for a stock 4.3 chevy. Somehow I found a video on YouTube and that video mentions Code59.org I registered there and watched the video sever times and they make it look so simple but I'm totally lost. Any one who wants to point this greenhorn in the right direction feel free. :)

[dave w]

Sometimes it helps if you have someone with TunerPro RT experience set up the Laptop with you. Maybe there is someone local to you to help out?

dave w

[ony]

did you down load the driver from tp web site for your cable?

[1great40]

After everyone went to bed last night and I could spend some quality time with TunerPRO. I believe it's configured. I just didn't feel like playing in the garage at 1 AM to try it out, But I found some stuff Mark has published links to in one of his posts and I got the $42 BIN and the other 2 definition files so now my TunerPro window has all of the files showing in the header. I couldn't find a BIN for the exact PROM I have (AKMH) But I did download one that's supposed to be for a 4.3 model years 88-91, 700R4 . I'm thinking this just might work. Right now I'm just trying to look at IAC counts. I have been told that I will need to start the data flow with the 10K resistor in place but once it starts, I can remove the resistor and see actual data at normal idle speed. I hope the guy was right.

Yes Ony, When I got the cable, it came with a CD containing the drivers. I thought I would use the drivers that came with the cable. The guy who sold me the cable claims compatibility with TP. It was't unlike the drivers I had to load when I set up the Actron Dashboard on my computer to view data from the Actron scanner that I borrowed.

Right now I think the cable/drivers are correct. Thanks for asking!

[dave w]

Congratulations! As far as I know, the 10K resistor is Not Needed for $42 data logging.

dave w

[jim_in_dorris]

No, the 10k resistor should not be used on $42 data logging.

[1great40]

Well, I finally got TP talking to my truck. It seems I had a com port problem but that's straightened out. The good news is that the IAC counts are about 10-13 in park but they barely go up at all, maybe to 15 in drive. Also the software is reporting that it's in closed loop operation, but the idle is open loop. What does that mean? Am I correct to assume that the computer cannot achieve target idle if the engine is operating in open loop idle mode? I'm going to need some help on how to log data that I can post up so minds greater than mine (almost anyone) can comment on it.

[jim_in_dorris]

Some bins are open loop idle, the go closed loop shortly after the vehicle starts moving. If the software says it's closed loop, then you are running a closed loop bin, better still. It should go closed loop when it warms up. to Data log, do this:
start your vehicle first.
1: in the Acquisition menu, choose start/stop data scan (ctrl F4)
2: to record, after starting a data scan, choose start recording from the same menu (Ctrl Alt Space)
3. to stop recording choose stop from the same menu (ctrl space)
4. name your log file
then you can upload it here to get looked at.

[1great40]

Thank you for the lesson Jim! I followed your instructions and I'm attaching my first data log!

[ony]

DO YOU HAVE THE CAPABLITY TO BURN YOUR OWN CHIPS"""?

[1great40]

Let me assure you,if I have ever burned a chip, it has been totally unintentional! No, I do not have the hardware or the expertise to program my own chips. Mark made me a chip, all i needed changed was the idle speed but it didn't work. That's what got me into TP. I thought that all it took to get the computer to control the idle was a correct minimum air setting, no pulses from the VSS and the engine to be operating in closed loop.

Right now I am using the stock PROM but I'm toying with the idea of installing Mark's modified prom and seeing what happens, since I have reset the minimum air setting. All I was originally looking for was to boost the idle speed a little

[jim_in_dorris]

1 Great40. You are WAY LEAN In dangerous territory at idle. What fuel pressure are you running? Your AFR is way out of whack. You are running almost 17.5 to 1 AFR. I am seeing rich lean cross counts, so your O2 sensor is swinging like it is supposed to. I don't know if that is an async bin, but you are in async mode at idle. Pull you plugs and check them. You may need to add fuel pressure as a first step in gettin your fuel close.

[1great40]

Thanks for finding that Jim. I will check the fuel pressure. I suppose that's why my BLM values seemed out of whack? Can you please explain async bin and and async idle mode.

[jim_in_dorris]

Asynchronous fueling is both injectors firing each DRP (Distributor Reference Pulse)

Synchronous fueling is alternating injector firing each DRP (Distributor Reference Pulse)

http://www.gearhead-efi.com/Fuel-Inj...Asynch-fueling (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1359-Synch-vs-Asynch-fueling)


What bin are you using. Don't get to confused, Async fueling adjusts the injector pulse width to a smaller value, so less fuel. My truck used to go Async all the time, then I put in the correct bin and now it doesn't do that. It can make tuning difficult, most guys like to run Sync fueling. If you have a copy of the bin you are using loaded in tunerpro, the flag "Synchronous Fuel At Idle" may be unchecked. You can only change flags by burning a new chip, so we will work first with fuel pressure to get you out of the lean area. Then we can adjust the pulse width when you start burning chips. Once it is close, then you can adjust your fuel mapping then spark.

[1great40]

Thank you again! I'm really confused about the bin. Correct me, but is the bin not the file that's burned into the PROM? If that's the case, how then can I accurately read what the engine is doing if I don't have the same exact bin loaded in TP as I have in my PROM, or am I missing something?

[steveo]

the bin and what the ecm puts out for diagnostic data are seperate things.

you can check sync/async operation and other things via datalogging without having a bin at all

but it's most useful to have a copy of your working bin so you can do things like data tracing...

[jim_in_dorris]

Thanks steveo, It really is helpful, but not totally necessary until you want to start changing things. What BCC are you currently running 40?

[1great40]

Jim, The PROM says AKMH

[1great40]

First of all, let me take a minute to thank all of you guys who have commented and made suggestions about the problem I'm trying to troubleshoot. I'm in over my head here, but I feel less so because of the effort you're all making to help me. Hopefully, someday I will be able to constructively comment and help someone else here, but don't hold your breath :)

I have a gauge permanently mounted in the fuel line under the truck. This morning I fired the truck up and backed it out and checked the gauge. The needle vibrates some but it's reading about 11 1/2 psi. Which is right where I set it when I modified the stock fuel pressure regulator to work with the Holley inline pump. So, I'm guessing that the lean condition at idle is probably not from the fuel pressure.

I'm wondering however, the truck engine is bone stock with the exception of a 2" full dual exhaust with a crossover pipe and no cats. I remember well an old nova my brother had which had a habit of loosening the nuts that held the head pipe to the manifold, That thing would run like crap till the pipe was tightened.

I noted a small exhaust leak between the head pipe and the exhaust manifold, you couldn't hear it (well at least I couldn't) but you could feel it puffing out. This is on the side with the o2 sensor and it's ahead of the sensor. Obviously I'm going to fix that pronto but I'm wondering if there is sufficient backpressure in the exhaust system for the way the stock engine was calibrated. If I were to plug one pipe and force the exhaust from one side through the crossover tube and have everything come through one muffler, what should I be looking for as far as a change in values that I would read while logging data? I think it couldn't hurt to try that and then I'll post up another datalog. Then the all knowing sages of Gearhead-EFI can tell me if I'm deeper into the toilet than when I started.

[jim_in_dorris]

When I first got my PU, it had dual exhaust, no cats, not crossover. I had to add cats to get emissions legal, and noticed a huge improvement in how it ran. I can't say what yours will do, but plugging 1 side and forcing the exhaust out the other shouldn't hurt in the short run. The exhaust leak up-stream of the O2 sensor however will show lean, so fix that.

[1great40]

Tell me if I'm all wet, but from what I have read, I would have to actually run and drive the truck somewhat to see a change in the way the engine runs and data returned from the ECM. If I'm understanding things correctly, after some driving time, the BLM number should have shifted, indicating that the fuel trim numbers that the engine is working from are different. Is my understanding correct?

[jim_in_dorris]

Yes, fuel trims are learned over time. When I finally got the correct BIN in my ECM, I had to drive around for about a week to actually see the BLM's start to come close the where I want them.

[1great40]

I repaired the exhaust leak at the manifold. Then I stuffed a rag into one tail pipe and installed a cheapie tail pipe expander so that the rag couldn't blow out, effectively making a single exhaust system. Then I drove the truck about 40 miles. There is a marked improvement in the idle. In fact I would go as far as to say that it runs about as good as a pre-balance shaft 4.3 ever would. I will continue to put some miles on it and do another data log. It will be interesting to see if the idle AFR is where it's supposed to be, or at least close. This would certainly be the smoking gun as far as low backpressure causing a lean idle condition. If it's the case, now I have to become a tuner and figure out how to compensate the AFR for the dual exhaust, or just put a single exhaust system on the thing and be done with it. Once there is enough data gathered about the exhaust change, I would be curious to go back to the chip that Mark made for me to see how it runs with the single exhaust. The chip he made is supposed to bump up the idle speed and was modified for no EGR, AIR, and canister purge.

[1great40]

There's now about 200 miles on the makeshift single exhaust system and the engine idle is consistent every time I have used the truck since the change. I'm thinking it might be enough driving time to do another data log. I'll try it this afternoon and post it up, hopefully Jim or someone else who understands this stuff can comment on it. Thanks.

[1great40]

I took another couple data recordings tonight. When I first started looking at the data live, the number for the BLM was 151, I think that's a little lower than the first data log I did but the number was still in red, so I'm assuming that it's not a great value. A few minutes later I noticed that the BLM number had dropped to 141 and was no longer red, I'm assuming that this is a step (or steps) in the right direction. I'm am uploading both sets of data. Hopefully someone can comment on this new information. If it does show that the AFR is not as lean as before, this would indicate the dual exhaust does not have sufficient backpressure for the calibration that I have. Thanks for looking at the data.

[dave w]

The ideal BLM number is 128. Numbers above 128 are lean. The bigger the BLM above 128, the leaner the engine is running. Numbers below 128 are rich. The smaller the number below 128 the richer the engine is running. The BLM average in the two data logs was 141, which is lean. Usually BLM's between 123 ~ 133 are considered acceptable.

The INT is averaging close to 128, which is good.

I think (1.0 PSI) more fuel pressure will help get the BLM's closer to 128.

dave w

[jim_in_dorris]

I agree with Dave, try bumping your FP up. I think you should read the sync vs asynch thread on this forum. Almost all the 4.3 bins are asynch and are hard to tune. I think ony found a 4.3 synch bin, APAA or APAB that may make tuning easier.

[1great40]

Thanks for looking at the data. I should not have a problem raising the FP up a pound. I will post again after I reset it

[1great40]

Hi, I read lots of stuff about synch/asnych on here and frankly, I'm more confused than before! in any event, I did bump the fuel pressure from 11.5 to just under 13 PSI. Like I said, the gauge vibrates a bit so a perfect read is tough. I would have done it sooner but I had forgotten what type of screw I used when I modified the stock regulator in the TBI so I had to pull the whole injector pod off to remember I slotted the factory screw.

[1great40]

:mad1:Well, I have run the truck about 100 miles since I upped the fuel pressure. I did another log tonight. When I was monitoring the BLM was at 144 which I guess is a step backward. Then while I was recording the data, the BLM jumped up to 146 and the value displayed in red again. I take it this is not a good sign. I'm wondering if another bump in fuel pressure is warranted?

Here's the data:

[dave w]

:mad1:Well, I have run the truck about 100 miles since I upped the fuel pressure. I did another log tonight. When I was monitoring the BLM was at 144 which I guess is a step backward. Then while I was recording the data, the BLM jumped up to 146 and the value displayed in red again. I take it this is not a good sign. I'm wondering if another bump in fuel pressure is warranted?

Here's the data:

That was a very short data log.

Anyway, there are not many options available to you? Changing fuel pressure only? I think the best option for now would be to add more fuel pressure, maybe 15 PSI or 16 PSI. The first and foremost challenge to tuning is getting the Base Pulse Width (BPW) correctly set. Changing the fuel pressure to a higher pressure has the same effect as increasing the BPW, which will lower the BLM's.

Having the ability the make changes to the PROM programming is very helpful, maybe even mandatory for your TBI system to run correctly? You have made great progress in getting data logs posted!:thumbsup: I don't think it was a step back, I think it was a huge leap forward to learn TBI tuning ... trial and error.

dave w

[1great40]

Thanks! I guess it's true that without the ability to make changes to the programming, all I can do right now is bump the fuel pressure. I'm having a bit of a problem with the whole concept of "tuning" though. The engine is bone stock, with the exception of the exhaust system, so I need to be sure that I'm not masking another problem by trying to tune my way out of it. I'm just being cautious here and trying not to change a whole bunch of stuff at once otherwise I'll never know which change has which effect. It is an interesting way of doing things though with a computer as opposed to wrenches! I will up the fuel pressure a little more and see what happens. It seems to make sense that in the absence of making the injector pulse width larger, higher pressure without lengthening the pulse should yield a richer mixture.

[ony]

that was a short log, get some hyway log time you might try the chip eagle mark adjusted and see if it is closer. the blm proble go up as you are driving most chips I have had in my v6 would have blms in the 140's till I changed the ve table. also 4.3 v6's run a higher scotck number .512-.540 instead of .451 like v/8's for some reason. when the egr is called for it will cut the pulse with down causing blms to raise . it is proble in the tune int. trying to take away fuel, blm trying to add fuel I only seen a short idle log.

[ony]

if you will get a long data log and post it I will try to make you a starter chip and send it to you from a bin I found. my v6 is a vortec in a 91 model which they didn't make. I have had better luck with a 288 ecm be cause I am not a pro tuner. I will send you a chip if I can find a 2732 that I can erase and reprogram. I have several of these. my truck is a standerd trans so I would be tunning blind if you are interested post a data log and give me your mailing address in a personal e mail or message on the gearhead sight. how many rpms do you want it to idle at, are you running a cat, are you running the egr, what part of the country are you located so we can set open loop fuel an spark. :innocent:

[1great40]

Thank you for the offer! I did get under the truck tonight to get a better read on the fuel pressure. Turns out it wasn't as high as I thought. It took me about an hour to come up with a small tool to get into the screw of the pressure regulator but I have a solid 12.5 to 13 PSI of fuel pressure now. The idle is better than ever and the idle speed came up some too. It's idling at a solid 600 RPM in gear now, that's where just about every GM V6 seems to idle and the idle quality is pretty darn good. This is the type of outcome I have been looking for... just getting the engine to run correctly with a stock calibration. As mentioned, I didn't want to "mask" something by tuning. Of course there's nothing wrong with a good tune, but the engine should be running correctly to begin with. I will run it like this for a while, then do another data log. I'm not sure why the last one was so short, pilot error I guess. It will be interesting to see where the BLM number settles in at and whether or not the engine needs a custom PROM once I try the dual exhaust again. There's still the typical V6 vibration at idle, it's just very slight, but this is not a balance shaft engine and possibly a RPM recalibration will be in order in the future. Stay tuned... (no pun intended)

[ony]

glad to hear your getting good results.:happy:

[1great40]

I drove the truck around quite a bit this morning, this is the best it has run since it was first out into service. To be cautious, before there are any other changes made, i plan to do another data log and check the BLM value. If it's good, then I need to decide what to do next...do I try the chip Mark made which sets the idle to about 700 RPM and that should eliminate the little V6 vibration and call it a day? Do I leave the chip stock and try to up the fuel pressure just alittle more to allow it to run OK with the dual exhaust or do I attempt to have a chip made which encompasses the changes that Mark made (higher idle, no EGR, AIR and Purge) plus an altered fuel table or VE table or whatever the correct name is to allow the Fuel pressure to stay under 13 PSI. Right now it's just under 13 PSI.

Thanks so much for everyone's help.

[ony]

if it is running pretty good I would get a data log and see where you are at, it takes several restarts from a cold engine to fully warmed up for the ecm to finally diciede if it is done programming all it can program. it may get smooth as silk or go the other way after it is run a few times.:popcorn:

[1great40]

Put about another hundred miles one truck today. The check engine light came on but reset itself when I restarted the engine. The truck is running really well and there is evidence of black in the one active tailpipe. I'm going to do another log tonight hopefully the BLM number is in a good range. I think a new chip is in order though, I would like to raise the idle by about 50 rpm and disable EGR, AIR and purge. The chip I have from Mark does all that stuff but the idle is 725, the current stock idle is about 600. Once I'm sure that the lean condition has been addressed by the fuel pressure change, then I think I need to try Marks chip again.

Another thought, if the BLM is below 128, would it make sense to switch back to the dual exhaust and see what effect it has on the BLM value?

[jim_in_dorris]

If your BLM goes below 120, and you are getting soot in the active tail pipe, I would definitely try full dual exhaust again. At least get some data logging in to see where you are at.

[1great40]

I ran the truck out to a cruise night tonight and when I got home, the CEL was on. I fired up TunerPro and did another data log:The CEL was an EGR error, which I think will go away with the modified chip. The BLM was encouraging at 130-133. The bump in fuel pressure certainly did get it richer. I'm thinking of making the pressure just a little higher and trying the dual exhaust again/ What do you guys think?

[dave w]

I ran the truck out to a cruise night tonight and when I got home, the CEL was on. I fired up TunerPro and did another data log:The CEL was an EGR error, which I think will go away with the modified chip. The BLM was encouraging at 130-133. The bump in fuel pressure certainly did get it richer. I'm thinking of making the pressure just a little higher and trying the dual exhaust again/ What do you guys think?

I like that plan.

dave w

[ony]

I would try eagle marks chip , if the egr is disabled it will bring blms down in places the the egr is called for, it sounds like your closing in on the problems. :happy:

[steveo]

130-133 is close. that's skew a couple percent at some kinda fueling constant or table and call it good. that difference could even be from an unaccounted for percentage of ethanol in your fuel or something like that.

you want to get it the other direction, though. 123-125 or so. then fine tune it to try to get it closer if you even care (you shouldn't)

[1great40]

Hi all. Today I installed the PROM that Eagle Mark cooked up for me, just to see how the truck would run. The good news is that it runs exactly like the stock PROM. The bad news is that it runs exactly like the stock PROM. The whole point in having the custom PROM was to have the idle set to 725 RPM. I know he addressed things like EGR, AIR, etc but I was disappointed that there is no change in the idle speed. I'm not sure what I'm missing here. What sort of magic does it take to change the idle speed? The odd thing is that when I first tried this prom, I was observing the RPM with an Actron scanner. That scanner only works in 10k mode. Mark told me he defaulted all the idle values to 725, that included the idle speed in 10K mode, which is usually 1000 RPM. When the scanner was attached, the engine idled at 725 RPM in park and 725 RPM in drive.

Anyone have any suggestions?

[dave w]

Hi all. Today I installed the PROM that Eagle Mark cooked up for me, just to see how the truck would run. The good news is that it runs exactly like the stock PROM. The bad news is that it runs exactly like the stock PROM. The whole point in having the custom PROM was to have the idle set to 725 RPM. I know he addressed things like EGR, AIR, etc but I was disappointed that there is no change in the idle speed. I'm not sure what I'm missing here. What sort of magic does it take to change the idle speed? The odd thing is that when I first tried this prom, I was observing the RPM with an Actron scanner. That scanner only works in 10k mode. Mark told me he defaulted all the idle values to 725, that included the idle speed in 10K mode, which is usually 1000 RPM. When the scanner was attached, the engine idled at 725 RPM in park and 725 RPM in drive.

Anyone have any suggestions?

The TunerPro parameter search shows about 20 idle parameters for the '7747 ECM. See attached screen shot. Usually the Desired IAC Idle C/L (closed loop) Speed table has the biggest effect on idle speed. I recommend an IAC minimum air adjustment of 10 ~ 20 steps prior to PROM chip changes.

dave w

[1great40]

Last time I checked my IAC count was about 12. How do I get to that screen you posted in Tuner Pro?

[dave w]

How do I get to that screen you posted in Tuner Pro?

Tools ... Parameter Finder ... See attached screen shot.

dave w

[lionelhutz]

Last time I checked my IAC count was about 12. How do I get to that screen you posted in Tuner Pro?

Ever try adjusting the idle stop screw? The rpm should stay the same and IAC should do the opposite of how you turn the idle stop screw until you run out of IAC steps. For example, if you back the screw out to close the throttle blades then the IAC should open to maintain the idle rpm. Try it, close the throttle blades and bring the IAC counts up to into the 40-60 range and see if the idle is still too high.

[EagleMark]

If the IAC count is 12 when vehicle is totally warmed up after a highway drive while stopped in drive? Perfect! Litte higher IAC count when neutral...

If idle is higher/lower RPM then desired? Change it in chip.

[lionelhutz]

But in neutral with no engine load wouldn't the rpm rise unless the IAC motor closed more, not opened more???

At any rate, I would try closing the throttle blades more and see what happens.

[EagleMark]

But in neutral with no engine load wouldn't the rpm rise unless the IAC motor closed more, not opened more??? .Your right, lower IAC... never let go to 0 IAC counts though.

[1great40]

Lionel, I'm not having a problem with a high idle speed, the idle is too low. Right now the IAC numbers are around 12 in park and a little higher in drive. From what I have observed, I want to have the largest quantity of the idle air coming by the throttle plate and a minimum admitted through the IAC without the IAC ever going to zero. When the throttle on a TBI engine is closed too much, it will still idle by virtue of the IAC admitting air but that air then has to mix with a dribble if fuel dripping past a closed throttle plate, not the best scenario for getting good vaporization. The more fuel spray that gets by the throttle plates, the better it mixes with the air.
So, the minimum air setting seems to be just fine, the ECM commands a high idle when the engine starts, the engine also goes to the correct speed when in 10K mode. As of now I'm pretty confident that the IAC is working, the ECM is working and the last piece of the puzzle is to use TunerPro to see what the actual values for idle speed are in the PROM. The stock PROM seems to make the engine idle at 600 RPM. The Prom that I'm using now that EagleMark made for me is supposed to have the idle set to 725 but with this PROM, the engine idles at about 550. First chance I get, I'm going to fire up the truck and look at the values. I understand there are many idle speed values for different conditions so, I'm at the beginning of another learning curve. Hopefully, this will be as simple as getting the PROM re-programmed but if the values are correct and the speed is still not right, I don't know where to look next!

[EagleMark]

Idle RPM is not accurate on this ECM, so at this point it needs to read higher. I need to send another chip with an additional 100 RPM. But until I get home I don't know of anoter way.

[1great40]

EagleMark, do you need me to mail the other chip to you?

[EagleMark]

Problem is I have been in hospital and rehabilitation since I did your chip and have no way to burn and mail another. But have someone who will, just need to contact him.

[1great40]

It's been a few weeks since I last posted. Eagle Mark said that the speed control on the ECM that I'm using is not too precise and that another bump in the idle speed would be in order. That got me to thinking. Once the truck is in gear if I'm stopped and I crack the throttle with my foot, and get the engine up to about 675 to 700 RPM, everything feels fine.

From what I understand, the ECM looks at the TPS voltage when the engine is started and uses that value as the idle TPS voltage. If you fiddle with the screw you can raise the idle speed, only for that one start/run cycle. If you stop and restart the engine after moving the screw, the ECM looks at the "new" TPS voltage and calls that the idle TPS voltage. So, once the minimum air is set, you can't play with it any more to try to set the idle speed.
But, once the engine is running, any movement of the throttle shaft has a corresponding change in the TPS voltage so the ECM doesn't try to force the engine speed, you're doing it with your foot.

My next step was to make a secondary idle stop so that I could "fake" the idle speed. I made a small block of aluminum with a second idle stop screw and attached it to the throttle body, right next to the minimum air screw. Once the engine is started and the ECM knows the idle TPS voltage, I could raise the idle speed with my new "idle stop screw". I could set the idle speed manually and it would return to the same speed every time the vehicle came to a stop. I would let the engine idle for several minutes in gear to see if the ECM tried to undo what I was trying to accomplish. Fortunately, I faked out the computer.

Obviously, it's highly impractical to back the screw off every time you shut off the engine and then reset it once the engine is restarted, but I did prove that the computer can be faked out and the idle speed can be set manually, at any speed I needed.

The next step is to automate this process. I ordered a continuous duty 12V "push" type solenoid from McMaster-Carr industrial supply. The solenoid has 30 oz. of force. I fabricated a bracket that attached the solenoid to the throttle body assembly. The actuating rod of the solenoid was set up to push on the boss on the throttle arm where the throttle cable attaches. I machined an eccentric cam that fit over the boss of the throttle arm and locked in place with a set screw. Rotating the cam with the solenoid actuated opens or closes the throttle plate. I have actuated the solenoid by connecting it to the battery and it moves the throttle no problem. Once the correct speed is obtained, the set screw can be locked.

My plan is to utilize the P/N switch that currently grounds the B-10 line to the ECM in park. I will add a SPDT relay and tie one side of the relay coil to a 12V signal that is switched with the ignition. When power is applied to the relay and the transmission is in park, the relay will actuate.
The B-10 line to the ECM will be connected through the normally open contacts to ground, so as soon as the ignition switch is turned on, the contacts ground the B-10 line to the ECM, just like a normal setup. Once the transmission is shifted out of park, the ground to the relay coil goes away, and the B-10 line is ungrounded, just like a normal set up. The other set of contacts in the relay now close and apply power to the idle stop solenoid, kicking up the idle when the truck is in gear.

As of now,the solenoid and the mechanical part of this set up is working. The next step is the wiring. Stay Tuned.

[damanx]

Love the ingenuity, but I have a couple of questions.

(Note that I am not an expert, but since I am running TBI with the 1227747 ECM on an engine that GM never made with the 1227747 and TBI combo, I had similar issues with finding the lowest, smoothest idle speed.)

In a thread you started about "setting up your tbi", you stated that you had set up the timing per the manual provided with the harness.

Where did that manual tell you to set the timing?

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1700-Setting-up-my-TBI&p=21107&viewfull=1#post21107

What I am curious about is that if you are running a pretty much stock engine with it's matching ECM and sensors, did the base timing adjustment in the painless manual match up with the base timing value programmed into the BIN file?

Unless I missed something in your posts, I did not see anything that indicated to what value you set the base timing at.

Also, in regards to the "open mode idle in drive" , my engine does that, and, seems to idle better, although I don't recall what all controls that. I do remember that it seems that in general, slightly rich at idle is what you want, but don't recall if that is idle park, or idle in drive.

If I am out of line asking any of the above, please let me know.

[1great40]

I think I used the term "manual" to refer to more than one book. The painless manual tells how to set the timing but the actual spec came from some other book I had.

I set the timing to 0 degrees.

I know now my setup is a round about way of addressing the idle issue but I thought it may be useful to someone else.

[Fast355]

I love the ingenuity but in this case it is simply not needed. To adjust the minimum idle rate, I open the throttle body screw 3-4 turns. Then jumper the ALDL A-B and turn the key on, wait 20 seconds for the IAC to fully close, then disconnect the IAC. Then remove the jumper and start the engine and work down from a higher RPM. Set the idle RPM for 750 rpm in P/N with the IAC closed off. Then when you reconnect the IAC and restart the engine it will idle at 750 and a little lower in drive. These older ECMs are pretty leniant with idle speed and setting idle speed control codes.

[damanx]

I think I used the term "manual" to refer to more than one book. The painless manual tells how to set the timing but the actual spec came from some other book I had.

I set the timing to 0 degrees.

I know now my setup is a round about way of addressing the idle issue but I thought it may be useful to someone else.

What does the base timing parameter show in TunerPro for the bin you are using? I am only curious because you had stated that the original eprom was a "AKMH" bin and wasn't sure of the new one.

[1great40]

I love the ingenuity but in this case it is simply not needed. To adjust the minimum idle rate, I open the throttle body screw 3-4 turns. Then jumper the ALDL A-B and turn the key on, wait 20 seconds for the IAC to fully close, then disconnect the IAC. Then remove the jumper and start the engine and work down from a higher RPM. Set the idle RPM for 750 rpm in P/N with the IAC closed off. Then when you reconnect the IAC and restart the engine it will idle at 750 and a little lower in drive. These older ECMs are pretty leniant with idle speed and setting idle speed control codes.

This is an interesting concept. The only thing about it is that it would seem to let the engine idle with 0 IAC counts, which I always thought from what I have read is a NO-NO. Something about the IAC pintle getting stuck in the throttle body if it has no headroom. But in thinking about what you have described it should work. One thing I have noticed in fooling around with the minimum air setting is if I do just set the idle speed where the engine idles smoothly in drive, it's running way too fast in park. My solution, although somewhat more complicated would keep the idle speed in park and the idle speed in drive fairly constant.

As far as the timing value in TunerPro, I need to look at that. I had just assumed that EagleMark had not changed it from stock when he burned my new PROM.

Of course since this is a forum of the best minds in the fuel injection business, I would love to hear from other guys who may have tried this.
As always, thanks for your help.

[damanx]

I was just curious about the timing. I'm pretty sure that if Mark had worked a BIN file and the timing was changed in it, then he would have told you to verify your base timing to match the BIN file.

Seems odd that you'd have to resort to doing this for something that automatically controlled if all your sensors and ECM is good.

Here is something you might want to read through. (beware that some pages are out of order).

http://igor.chudov.com/manuals/TBI_Fuel_Control.pdf

[1great40]

I was just curious about the timing. I'm pretty sure that if Mark had worked a BIN file and the timing was changed in it, then he would have told you to verify your base timing to match the BIN file.

Seems odd that you'd have to resort to doing this for something that automatically controlled if all your sensors and ECM is good.

Here is something you might want to read through. (beware that some pages are out of order).

http://igor.chudov.com/manuals/TBI_Fuel_Control.pdf


According to the information you just gave me, the engine is idling exactly where it should for a stock configuration. I had Mark make a new PROM because I wanted a higher idle speed. My 4.3 is a pre balance shaft model (1989) and it's in a street rod. My gut feel is that my drivetrain isolation is probably not as good as what they did at the factory and since these engines aren't the smoothest idling in the world, I opted to get a PROM burned that would bump the idle up a little. Mark also changed things in the PROM to reflect the fact that I'm not using EGR, AIR, or purge. So my only problem is that the idle speed is too low for a nice smooth feel. I have played with upping the fuel pressure to compensate for a dual exhaust with turbo mufflers vs a single exhaust with a street muffler and a cat, since the engine was idling too lean. The fuel pressure change really got the engine idling a lot better, probably as good as it ever would. Now I'm just trying to finesse it to the point where I'm happy with it

[1great40]

Well I need to pat myself on the back for doing a great job on the idle stop solenoid install. But have to give an even bigger pat to the General, whos' little '747 has outsmarted me again.

What worked in theory and what worked manually doesn't work when it's automated and the idle speed with the solenoid not actuated keeps climbing.

So, I guess I can try what Fast 355 suggested and let the thing idle with 0 IAC counts when it's hard against the stop screw, or I can let Eaglemark have another shot at frying up a fresh PROM with more speed dialed in, or I need to delay the actuation of the solenoid until after the truck is in gear and the IAC puts the idle where it thinks it should be and then I bump it a little from there.

An old Rochester 2 barrel is looking mighty good about now :)

[steveo]

An old Rochester 2 barrel is looking mighty good about now :)

i know it seems that way, but it's just as easy to get a 'carb quality' idle from fuel injection as it is a carb, which is just fixed idle air. you can just disable the IAC for anything but cold start, disable closed loop, and run 'er a bit rich.

you're trying to achieve something better than what a carb would give you, which takes a bunch of work and experimentation, but is totally rewarding.

in the end, there's nothing wrong with 0 iac steps when it's hot, though?

the only problem with that in a tbi system seems to be that if something is going to cause idle to -increase- (vacuum leak either expected or not... change in the weather..whatever), the computer is helpless to do anything about it.


So my only problem is that the idle speed is too low for a nice smooth feel.

you can usually force pretty smooth n low idle out of any engine with the assistance of electronic timing control.. almost every engine seems to want more fuel, more timing, and repeat, until idle smooths. this can be done completely manually like a carb n points motor, just turning the distributor and jacking around with fuel pressure and the throttle plate. then just set it back to stock and the changes can be placed in the bin?

[ony]

it kindof sounds like the stall saver inable disable needs set to match the rpms you are trying to idle at in your bin file. + 2-4 degree timming increase at idele make a lot of differents on idle smoothnes as stevo said. my 4.3 is a standard trans I have it set to 16.5 in the bin iam running where as it was 12.5 makes it idle a little better an helps taking off from a dead stop.[normal driving] .

[damanx]

it kindof sounds like the stall saver inable disable needs set to match the rpms you are trying to idle at in your bin file. + 2-4 degree timming increase at idele make a lot of differents on idle smoothnes as stevo said. my 4.3 is a standard trans I have it set to 16.5 in the bin iam running where as it was 12.5 makes it idle a little better an helps taking off from a dead stop.[normal driving] .

Ony, you reminded me of my issues when I first started playing with the timing table on my truck. (note that it's a TBI on an engine that was originally a SPFI).

Would advancing the timing in the idle rpm/map areas of the spark table help him?

[lionelhutz]

I've played with a few 7747 tunes and never had one idle 175-200 rpm off of what was programmed. I recall the idle typically varied by 25-50rpm.

[ony]

that is what mine does 50-75 rpms ,I think he had it change to a higher rpm and the disable inable may need adjusted in his bin . damanx the smoothest idle that I ever got on my 4.3 was a 747 with a modified apab bin timming at idle was 9 degrezz idle rpm 600 but its a std trans and I didn't like the way it took off from a stop.

[1great40]

Needless to say I hit the sack somewhat defeated but hopefully optimistic for a fix. The next morning I fired the truck up to head to church and it ran the way I expected it to. Fast idle when cold, 600-650 in park and about 700 in drive. Put it back in park and it goes. back to 600-650.

the next step is to drop my idle in drive just a hair more so it's right between smooth and making the truck creep in gear. We'll see how this goes.

[Fast355]

Needless to say I hit the sack somewhat defeated but hopefully optimistic for a fix. The next morning I fired the truck up to head to church and it ran the way I expected it to. Fast idle when cold, 600-650 in park and about 700 in drive. Put it back in park and it goes. back to 600-650.

the next step is to drop my idle in drive just a hair more so it's right between smooth and making the truck creep in gear. We'll see how this goes.

Sounds like your P/N switch might be inverted if you are using one. Park idle should be higher than Drive idle.

[1great40]

Sounds like your P/N switch might be inverted if you are using one. Park idle should be higher than Drive idle.


Good observation Fast 355 but that's part of the plan! My problem was that even though I had a pretty good idle in park, when the engine loaded by putting it in drive, the vibration or should I say resonance was annoying. I added the solenoid to just kick up the idle a bit in drive. Right now it's idling at 700 in drive but returns to 600-650 in park because the solenoid deactivates in park. I'm going to bring the idle in drive down a little more so it's about the same as the unloaded idle in park.

My IAC counts are about 10-12 in park but only hop up to 19 in drive so the engine is running slower in drive than in park without the kick up solenoid

[1great40]

Hello all, I have been away from the board for a bit. Just reporting back that the solenoid fix is not reliable. I'm guessing it has something to do with when the ECM looks at the TPS voltage for it's baseline. What I'm thinking is that if I put the truck in gear too soon after starting, the ECM reads the voltage from the TPS but the TPS voltage is elevated by virtue of the fact that the solenoid as moved the throttle slightly and this screws things up. When it does work, The engine idles about 650 or so RPM in park and then kicks up slightly by the solenoid when in drive. When it doesn't work, the engine idles at about 900 rpm and drops down to about 750 or so in drive. So my attempt to fool the ECM isn't working. I'm guessing I will need another PROM with the idle set up a little higher than the last one EagleMark made for me.

I might try the suggestion about running 0 IAC counts at idle by messing with the minimum air setting again, just letting the engine run at about 800 RPM in park and letting it drop down from there in Drive.

For a while I thought I knew what was going on with this engine but now I'm more baffled than ever :)

[telecasterfool]

Hello all, I am very new to tuning, but I have a 4.3 v6- now running a 1227747 ecm with a AMTU 5.0L $42 bin. I went through the stock $AO bin and transferred all the pertinent data to a $42 4.3auto bin, but it was ASYNCH, and now I've transferred to a Synch bin. My point here is though- there is an RPM for Drive setting, and one for Park/N. My truck idles at the correct settings for both with 10 degrees timing. It has a very mild Comp Cams 260AHR camshaft. Hope this helps

[ony]

you may have better luck idling with an acyn bin till you learn tunning a little more.what are the spec. on your cam compared to a stock cam, I have a v6 also and was thinking of a rebuild and a light cam up grade.

[telecasterfool]

Hi Ony- here is the spec:
COMP Cams 249-CL09-412-8
Exhaust Valve Lift (in.)
0.5
Intake Valve Lift (in.)
0.500
RPM Range
1000-7000
Int. Duration @ .050 in. (Deg)
206
Exh. Duration @ .050 in. (Deg)
210
Int. Duration Advertised (Deg)
260
Exh. Duration Advertised (Deg)
266
Lifter Type
Hydraulic Roller
Usage
Street/Performance
Engine Make/Size
Chevy 200-262 (90 Degree)



I was mistaken on the timing: it's about 26 degrees at idle. So far the idle hasn't been too bad- only been a couple days. I was able to emulate and tune the open loop idle last night. This cam is very mild, but I was just looking for a slight step up from stock with good low end torque. I used the GM performance corvette beehive valvesprings and the Comp Cams magnum roller rocker arms. No head work required if you go this route.

I still have all the info if you need it. This site has been such a big help, I'd love to help someone else.

[telecasterfool]

Ony- I assume you have done some tuning on your 4.3 V6. Would you let me take a look at your bin file? It's ok if you don't want to- don't want to overstep the bounds

thanks

[ony]

probley should start your own thread, here is a bin for a standard shift that is a sync bin, my truck is a std trans I am running a 288 ecm right now this bin is for a 7747 it has lean cruise employed in it. you might use the timming and ve tables as a starting point.

[telecasterfool]

Thank you Ony!

[1great40]

Just when you guys had thought I had dried up and blown away, I'm back. I saw the thread taking a different direction and that made me feel a little better about nagging you guys with my problems. It seems the discussion has helped others!

As I had mentioned, the solenoid idea was a lot better in theory than in reality. So that's history. BTW I have a really powerful 12V push type solenoid for sale really cheap :)

Someone here had noticed in my data that my BLM value was way off. Way too lean. The first thing I did was plug up one side of the duals and force all the exhaust through one muffler. BLM value dropped quite a bit. Then I went on to adjust the fuel pressure. Last time I checked the BLM value was about 133 or so, down from 150. I haven't tried to drop it any more because I think I'm out of adjustment on my home-modified OE fuel pressure regulator. Enriching the A/F ratio has been the most significant improvement in the idle quality since the truck has been on the road.

Still looking for the Holy Grail of pre balance shaft Chevy V-6 idle, I decided to try the 0 or near 0 IAC count approach, except I didn't do it by zeroing out the IAC with the computer. I simply raised the minimum air stop slightly until I found a sweet spot in the idle while in drive, which turned out to be 600 RPM. somewhat less than what I had asked EagleMark for initially because when he burned my PROM, I hadn't addressed the BLM issue yet. I wasn't even aware of the problem until it was pointed out to me. BTW I'm running the stock PROM again. Of course on the next restart, the IAC simply throttled the engine down a little to defeat the change I made. So, another little tweak of the minimum air screw was done, again to get me back to 600 RPM in drive.

I have been kicked in the ass often enough by this engine to be very wary of declaring victory over the General and his legions of software engineers, however, the truck is now idling rock steady and quite smooth at 600 RPM in drive and it climbs to 750 in park. The idle quality is close if not equal to my 2012 4.3 Sierra. Now all i need to do is unplug the 2nd muffler and see if my BLM value and idle quality hold.

[damanx]

Have you had any changes made to the VE and spark tables, or any other parameter for that matter?

Sure sounds like you are trying to force the ECM to operate out of it's programming by mechanical adjustments.

I don't know everything about the programming, but I think you are eventually going to have to make some changes in the programming.

[1great40]

Its a completely stock PROM that came out of the Astro van I got the engine out of. Forcing the ECM to operate outside of it's programming is exactly what I'm trying to do and from what I understand about how the ECM controls the idle, this is possible. Time will tell. I have already spent money on a failed attempt to fry up a new PROM since I didn't even have my A/F ratio in the ball park when I asked EagleMark to start changing stuff for me. I think from what I have read on other forums and my personal experience that a mail order PROM will require multiple iterations and multiple disappointments. This EFI thing is very likely something I wouldn't incorporate into my next project although, while I'm still a flaming rookie, I have learned a bunch of stuff that would certainly put me way up on the learning curve if I were to do it again. I guess my main frustration is that my initial intent was and still is to do a simple transplant of the EFI engine into another vehicle and get it to run as stock. This has proven not to be worth the time it has taken me to get there. I have no intention of buying a bunch of hardware and spend my free time burning PROMS in my garage, just to get 1 engine to run reasonably well.

[ony]

glad to hear you making progress. another member was having fueling issues after putting on custom duels last year I don't remember the thread.it was on a v/8. when you open the other muffler up the blm will proble go up, have you got a heated o2 sensor?

[1great40]

No, it's just a 1 wire 02 sensor

[damanx]

Its a completely stock PROM that came out of the Astro van I got the engine out of. Forcing the ECM to operate outside of it's programming is exactly what I'm trying to do and from what I understand about how the ECM controls the idle, this is possible. Time will tell. I have already spent money on a failed attempt to fry up a new PROM since I didn't even have my A/F ratio in the ball park when I asked EagleMark to start changing stuff for me. I think from what I have read on other forums and my personal experience that a mail order PROM will require multiple iterations and multiple disappointments. This EFI thing is very likely something I wouldn't incorporate into my next project although, while I'm still a flaming rookie, I have learned a bunch of stuff that would certainly put me way up on the learning curve if I were to do it again. I guess my main frustration is that my initial intent was and still is to do a simple transplant of the EFI engine into another vehicle and get it to run as stock. This has proven not to be worth the time it has taken me to get there. I have no intention of buying a bunch of hardware and spend my free time burning PROMS in my garage, just to get 1 engine to run reasonably well.


Here is my learning curve, I've installed a TBI on a GM 3.4L 60 degree V6 that never came from GM installed with TBI in any GM application. The TBI system came from a GM 2.8L engine.

I can tell you from my personal experience that one iteration of programming will not fix everything. Watching my logs, any minor changes in the VE and/or spark table, the effects aren't immediately seen in the first few minutes of driving after changing the PROMS, especially if you completely disconnect the ECM. I've got a ZIF socket installed, so I just swap the prom and drive. I'm still making changes, especially into areas of those tables that I don't touch too often. I'm also going to have to watch and make changes as summer takes full effect because I started tuning while not having to run the A/C. I don't expect to see much though.

I don't believe I'm the only one that would tell you that minor environmental changes do affect the BLM/INT values. I see it in my logs. I've had EagleMark remind me of this when I first started out because I was so focused on having the BLM's running 128 exactly regardless of environment. Just ain't going to happen.

You kind of contradict yourself when you state,

"I guess my main frustration is that my initial intent was and still is to do a simple transplant of the EFI engine into another vehicle and get it to run as stock. This has proven not to be worth the time it has taken me to get there. I have no intention of buying a bunch of hardware and spend my free time burning PROMS in my garage, just to get 1 engine to run reasonably well."

If the engine you are transplating the TBI to is the same as the engine the TBI came from, I can see the frustration, but dropping a TBI system on a different engine, it's just not going to be that simple.

The programmers and eprom erasers can be had for less than 75 bucks. You might find tuning a lot easier and less frustrating if you had your own or more frequent access to them. If you lived near me, I'd volunteer to help you on that.

I'm not trynig to be an a55, but it seems that you are looking for the easiest mechanical kluge to force them ECM to do things that it will always continue to fight doing when you could be reprogramming it with all the hassles you are having.

[ony]

I have forgot what type exhaust you have,if it is true duals 3cylenders would have a hard time heating the o2 sensor at idle to keep it in closed loop.thats why I ask if it was a 1 wire.

[1great40]

yeah, I guess I wasn't clear... 1989 GM Safari (Astro) Van 4.3...take it out of one vehicle with the ECM and bolt it into another. The differences I quickly learned were fuel pressure, even though the guys I bought my fuel pump from swore up and down I was good to go, I had to modify the internal TBI fuel pressure regulator to get the fuel pressure into acceptable (9-13 psi) range and then I had to adjust the fuel pressure to compensate for reduced backpressure at idle. That's why I kept mentioning the stock aspect. I was hoping to do minimal engineering to get the engine to run the same way it did in the donor vehicle. I wouldn't consider adapting TBI to an engine that wasn't running TBI to begin with, at least not for my first rodeo. I don't think you're trying to be an a55, you're right, I am looking for the easiest mechanical kludge and I may have found it :) Lets put it this way: when all you have is a hammer, everything becomes a nail.

Let me ask you this, If I'm going to run a TBI engine, with it's stock ECM in another vehicle, what would make me think that the ECU would have to be modified to get the engine to run the same way it did the day before I took it out?. I would think that since it was determined the fuel pressure and back pressure were wrong, the best thing to do would be to address the fuel pressure and backpressure, not change values in the PROM. I'm not sure where you got the impression that I'm looking for a rock solid 128 for my BLM come hell or high water. I never understood it to be necessary. All I said was that it was pointed out to me that the engine was running excessively lean, and I set out to address that issue by tuning the exhaust to more closely resemble the exhaust system the engine was initially calibrated around and adjust the fuel pressure towards the higher end of the factory specification, which results in an enriched mixture without changing the injector pulse width. Around here, we call it fixing what you know is broken before you try to fix anything else.
Ony,you make a good point about the 02 sensor. The exhaust is true duals with a crossover pipe. I believe I have noted only one instance where I saw the engine drop out of closed loop and that was after an extended period of idling. The exhaust is going to be changed to single soon. That's the way I'm running it right now by plugging one muffler anyway.

[damanx]

Let me ask you this, If I'm going to run a TBI engine, with it's stock ECM in another vehicle, what would make me think that the ECU would have to be modified to get the engine to run the same way it did the day before I took it out?. I would think that since it was determined the fuel pressure and back pressure were wrong, the best thing to do would be to address the fuel pressure and backpressure, not change values in the PROM.

This is where I am kind of confused because even though the engine and ECM came together, and then installed into a different vehicle, technically, I would not call the setup, "stock", as a whole.

Apparently there are enough differences in the fuel supply/return system, and, the exhaust system that have caused the issues you are having.

For my truck, it just so happens that the fuel supply line and return line are the same diameters, and honestly, I'm not aware of what my return line backpressure is. I just know that I'm running about 13 psi at idle and that my BLM's in the areas that I drive the most are pretty close.

For me, I took a 3.4L out of a camaro, installed it into my S15 truck. S15's never came with those. GM never mated TBI to the 3.4's either, but I did. A few others have done the same, but I know they've not done any tuning either.

In any case, over the course of a year and a half now, I've made more modifcations that have affected the blm/int tables.

One of which was adding Edelbrock long tube headers. Then, I went from a 2.8 throttle body with 1 3/8" bores to a 4.3 throttle body with 1 11/16" bores. Those changes alone caused me to have to up the fuel pressure a little bit along with adjusting the VE and timing tables.

If I may suggest, dump that single wire O2 sensor and get a heated 4 wire.

[1great40]

Hi Guys, I don't get back to Gearhead too much, and I know you all have nothing better to do than hang out and hope I'll post. I have been driving the truck for a few hundred miles now since I pushed it to the "0 IAC count" mode. I was only seeing an IAC count of about 10 or so anyway, so the change I made only really involved less than a half a turn on the minimum air setting. I have not logged any data yet since just about a hundred miles or so ago, I made a hard piped change to a single exhaust and then I had to disconnect the battery to do some electrical work, so I need to put a few miles on it. All in all it seems to be running well. It will be interesting to see where the BLM value falls, I just want to be sure it's still not running lean. The lack of cold hesitation I was initially experiencing along with a little blackness in the tailpipe are a seat of the pants indicator that it's richer than it was before I started fooling with it.