350 Vortec wi th 454 TBI running pig rich

[sturgillbd]

Your throttle blades need to close more. Adjust your bolt to where it allows the blades to close more. You still are idling above the commanded idle rpm. The IAC is going to 0 counts at idle. That is your IAC fault. If you are positive you no longer have vacuum leaks, you will have to start adjusting your idle VE table. Your BLMs are at 90 in most places. Your bin is set to allow a minimum BLM of 90. You may look at the text file that zuk1972 posted the link to. You have to look at the VE table in the text file carefully because the taableis layed out backwars to what you will see in the bin for BJYL. I would get the tuning spread sheet and fill in the running average from the datalog you just posted and follow the explaination in this thread. http://www.gearhead-efi.com/Fuel-Inj...ng-VE-Fueling&

What are the specs on the cam you are using in this engine?

[delcowizzid]

yes the iac is maxed needs throttle blades closed.where did the ecu originate from did it come with the TBI unit .with the writing on the top would allmost look like its maybe been modified for multi point injection .wording looks like injector driver mod and netres jumper on the memcal

[sturgillbd]

I didn't see that picture when I looked last night. I viewed the pics from my phone and missed that. If the sense resistors have been jumped, it will be operating the injectors in saturated mode. Rsicard, Pull cover off of PCM and blue cover off memcal. Send pics of the internals.

[rsicard]

Your throttle blades need to close more. Adjust your bolt to where it allows the blades to close more. You still are idling above the commanded idle rpm. The IAC is going to 0 counts at idle. That is your IAC fault. If you are positive you no longer have vacuum leaks, you will have to start adjusting your idle VE table. Your BLMs are at 90 in most places. Your bin is set to allow a minimum BLM of 90. You may look at the text file that zuk1972 posted the link to. You have to look at the VE table in the text file carefully because the taableis layed out backwars to what you will see in the bin for BJYL. I would get the tuning spread sheet and fill in the running average from the datalog you just posted and follow the explaination in this thread. http://www.gearhead-efi.com/Fuel-Inj...ng-VE-Fueling&

What are the specs on the cam you are using in this engine?

The camshaft being used is the LT-4 Hot Cam. Installed it and also installed new Crane Cams valve springs on the Vortec heads. Specs as follows. Understand what needs to be done to the VE tables. First need to get the ignition timing situation under control. What the ECU is commanding for timing has no relationship to what is being strobed on the balancer. Need help with that.

LT-4 Hot Cam Specs

Hot Camshaft (P/N 24502586) Specifications

Intake Exhaust
Lobe Lift 0.328” 0.328”

Valve Lift
@ 1.5 ratio 0.492” 0.492”
@ 1.6 ratio 0.525” 0.525”

Duration

@lash point 279° 287
@0.006 cam 272 281
@0.050 cam lift 210° 228°

Lobe Centerline 109° 115°

Lobe Separation 112°

[rsicard]

I didn't see that picture when I looked last night. I viewed the pics from my phone and missed that. If the sense resistors have been jumped, it will be operating the injectors in saturated mode. Rsicard, Pull cover off of PCM and blue cover off memcal. Send pics of the internals.

Using the ECU from a 1994 K2500 suburban that had the 454 bored and stroked to 489 cu in and Edelbrock conversion to batch port injection via the 16197427 ECU and Edelbrock binary chip. Performed the MemCal and sense resistor mods, as directed, and the engine ran poorly. Backed out the MemCal mod, left the sense resistors jumpered, then the engine ran as before.

Will remove the jumpers and open up the MemCal and take pictures. Not sure what is being looked for. Need to get the ignition timing situation figured out also. Please advise. Thanks.

[rsicard]

yes the iac is maxed needs throttle blades closed.where did the ecu originate from did it come with the TBI unit .with the writing on the top would allmost look like its maybe been modified for multi point injection .wording looks like injector driver mod and netres jumper on the memcal

ECU came from 1994 7.4L Suburban modded with Edelbrock batch port injection intake manifold. Need to remove jumpers, then use ECU as test subject on 350 Vortec with appropriate binary chip.

[sturgillbd]

On the pfi mod, most people jumper two pins in the memcal to convert from tbi to pfi. It changes the firing strategy on the injectors from tbi to pfi. There is a thread or two on this board concerning the mod. I am using my phone at the moment and my lunch break is about over. Hopefully the mod in the pcm is just jumpers soldered over the sense resistors.

[rsicard]

On the pfi mod, most people jumper two pins in the memcal to convert from tbi to pfi. It changes the firing strategy on the injectors from tbi to pfi. There is a thread or two on this board concerning the mod. I am using my phone at the moment and my lunch break is about over. Hopefully the mod in the pcm is just jumpers soldered over the sense resistors.

You have been the one most helpful. Greatly appreciate that. Do not want to interfere with your employment to make money. The '94 Sub and '95 pickup are two different projects. Using assets from '94 to test 350 Vortec destined for '95 pickup which at present has an oil burner 350 engine. As long as I had the LT-4 Hot Cam, installed it and new valve springs to get even better performance out of the 350 Vortec which has GOOD compression and GOOD leakdown numbers. Priority now is to get the ignition timing situation under control on the 350 Vortec using '94 sub ECU and Vortec binary chip. Once that is sorted out, then get into fixing IAC situation and tuning the VE tables. Please advise. Thanks.

[sturgillbd]

Take off the jumpers from the resistors in the ECM. I would run the engine and get it to operating temp. I would start a datalog and try to fill in as many of the cells in the history table as I could for near idle. I would then run the data through the spreadsheet to lean it out. It may take more than one datalog to do this. You will only be able to partially tune near idle considering you have no load on the engine with it running on a test stand. With vortec heads, the spark table will have to be modified because BJYL was a calibration for a tbi headed engine. There are vortec spark tables out there. http://www.gearhead-efi.com/Fuel-Inj...-Throttle-ONLY! There are guys on this board that do tuning for a reasonable price. The engine is going to have to be in a vehicle and be driven under load before it can be tuned correctly. The LT4 hotcam is also lowering the vacuum signal to the map and the ECM thinks the engine is under load at idle. This is not the ideal situation for someone first learning to recalibrate an ECM. It may be in your best interest to hire someone to help. Most tuners will not attempt to tune an engine on a test stand with no load.

[rsicard]

Take off the jumpers from the resistors in the ECM. I would run the engine and get it to operating temp. I would start a datalog and try to fill in as many of the cells in the history table as I could for near idle. I would then run the data through the spreadsheet to lean it out. It may take more than one datalog to do this. You will only be able to partially tune near idle considering you have no load on the engine with it running on a test stand. With vortec heads, the spark table will have to be modified because BJYL was a calibration for a tbi headed engine. There are vortec spark tables out there. http://www.gearhead-efi.com/Fuel-Inj...-Throttle-ONLY! There are guys on this board that do tuning for a reasonable price. The engine is going to have to be in a vehicle and be driven under load before it can be tuned correctly. The LT4 hotcam is also lowering the vacuum signal to the map and the ECM thinks the engine is under load at idle. This is not the ideal situation for someone first learning to recalibrate an ECM. It may be in your best interest to hire someone to help. Most tuners will not attempt to tune an engine on a test stand with no load.

Need to fix IGNITION FIRST then tune VE tables. Any thoughts about ignition timing. TunerPro readout totally different from strobe on balancer.

[rsicard]

I need to beat this to death. The timing numbers in TunerPro have absolutely NO CORRELATION with the timing light on the balancer. No sense in swapping out the engine in the '95 pickup UNTIL the timing issue is first sorted out. Here comes the risk, if transplanting the 350 Vortec in its present state into the '95 pickup, and the timing issue is not sorted out, I am really dead in the water. Things may be easire to sort out on the run-in stand. VERY much understand only the idle ignition and VE table stuff can be adjusted on the run-in stand. Likely the timing issue MAY change for the better if installing the 350 Vortec in the pickup. Yet the risk in my mind remains. Your thoughts, please, on the ignition timing issue.

[rsicard]

Need guidance on TunerPro with 16197427 ECU on how to make Knock Sensor input deaf. Somehow there has to be a correlation between timing number in TunerPro and that read on the balancer with timing light. Took extra time to make certain number 1 cylinder was a Top Dead Center when installing graduated balancer and custom timing pointer. Previously with a carb and HEI distributor, the timing was just as it should be. With this EFI, the timing issue reared its ugly head. Suspect EMI/RFI interference. Howell harness, on run-in stand is limited in lengths. Not sure how much separation of wiring can be achieved. Don't know if its radiated or conducted interference. Don't know which wires and inputs are affected. Don't have de-pinning tool to disconnect select wires from ECU to isolate issue.

Would be nice to invoke thoughts from others on this forum. Your thoughts please.

[sturgillbd]

Balancer inertia ring slipped? Check TDC mark with a piston stop in the spark plug hole on #1 cylinder. If the mark on the balancer lines up with 0deg mark on the timing cover, and the piston is at TDC on #1, the inertia ring has not slipped. Unplug bypass wire and set the distributor to 0 degrees advance with the engine idling with the timing light. Shut off engine and pull battery power to the ecm. Plug bypass wire back up. Reconnect battery. Restart engine and look at timing with light and compare to tunerpro. What ignition module are you running in the distributor? With all of the knock counts in the datalog, your ecm is retarding the timing (just a few degrees). Do you have the proper knock sensor installed? Knock sensor should be for a 1993,1994 or 1995 5.7 truck with ecm controlled auto transmission. The manual transmission sensor is different. Do you have the wire from the knock sensor tied to ECM pin B15? If you want to disable the knock sensor, set the Minimum Temperature for Knock Retard (under Knock Retard Parameters in Parameter Category View) to max which is 151.3C and burn the bin a chip or upload it to the emulator. Triple check your wiring from the distributor to the ecm. How close are your plug wires to your test stand harness? I saw some glitches in your datalog while replaying it. Is your timing chain new? I use Advanced $0D TP5 v251.xdf and $0D-16197427-V5.7.adx . These two files can be found here: http://www.gearhead-efi.com/Fuel-Inj...Information-0D . There are just a lot of different things that can cause your issues. I am using a 16197427 in my jeep. I have not seen the timing issues you have with my setup. I traced each wire and labeled them as I built the harness. I have patched my bin to control the electric fan and by following the instructions and wiring diagrams on this and other sites, everything has worked. I suggest you go over everything. If the timing advance at the balancer is that far off from what the tunerpro data shows, something is wrong whether it be electrical or mechanical.

I sincerely hope this helps

Brian

[sturgillbd]

Homemade pin tool. It is a piece of solid copper wire like used in grounding a meter base for electrical. 6ga solid. I drilled a small hole in one end and inserted a header pin from a piece of scrap electronics. Soldered the pin in and viola! The tool was dipped in liquid tin to slow the tarnishing of the copper but it isn't needed

[rsicard]

Balancer inertia ring slipped? Check TDC mark with a piston stop in the spark plug hole on #1 cylinder. If the mark on the balancer lines up with 0deg mark on the timing cover, and the piston is at TDC on #1, the inertia ring has not slipped. Unplug bypass wire and set the distributor to 0 degrees advance with the engine idling with the timing light. Shut off engine and pull battery power to the ecm. Plug bypass wire back up. Reconnect battery. Restart engine and look at timing with light and compare to tunerpro. What ignition module are you running in the distributor? With all of the knock counts in the datalog, your ecm is retarding the timing (just a few degrees). Do you have the proper knock sensor installed? Knock sensor should be for a 1993,1994 or 1995 5.7 truck with ecm controlled auto transmission. The manual transmission sensor is different. Do you have the wire from the knock sensor tied to ECM pin B15? If you want to disable the knock sensor, set the Minimum Temperature for Knock Retard (under Knock Retard Parameters in Parameter Category View) to max which is 151.3C and burn the bin a chip or upload it to the emulator. Triple check your wiring from the distributor to the ecm. How close are your plug wires to your test stand harness? I saw some glitches in your datalog while replaying it. Is your timing chain new? I use Advanced $0D TP5 v251.xdf and $0D-16197427-V5.7.adx . These two files can be found here: http://www.gearhead-efi.com/Fuel-Inj...Information-0D . There are just a lot of different things that can cause your issues. I am using a 16197427 in my jeep. I have not seen the timing issues you have with my setup. I traced each wire and labeled them as I built the harness. I have patched my bin to control the electric fan and by following the instructions and wiring diagrams on this and other sites, everything has worked. I suggest you go over everything. If the timing advance at the balancer is that far off from what the tunerpro data shows, something is wrong whether it be electrical or mechanical.

I sincerely hope this helps

Brian

Brian: You are very good at this stuff. Already confirmed the balancer and timing pointer. I use it as the truth in timing. Just soldered 3.3 Kohm resistor in the Knock Sensor line to ground. Routed it away from the distributor. Connected a Fluke Digital VOM across the 3.3 Kohm resistor and read approx 2.1 vdc. Also check the AC volts on the wire and it was in the low milli-volts which is VERY GOOD. Can check the Knock Sensor wire that should be connected to B15. Will use teh xdf and adx that you are using. I am going to tear apart the harness and re-route the TPS, MAP and Knock Sensor wiring as far away from the spark plug wiring. Think this may solve the ignition timing issue. Also may set the Min Temp for Knock Retard to max setting to disable knock function. Right now it is dark outside and would be better to test tomorrow morning. Will relay the results to you.

Regards,
Rolly
Tucson, Arizona