'94 LT1 F-Body/ $EE tuning change for '95 transmission (PWM)

**Vaild** · 07-22-2016

I need help and I don't know how to post but I have a 94 K1500 5 speed I am doing a v8 swap I have a 4.3 I am putting a 96 305 in my truck that Iswitch to tbi but I'm going to the junk yrd will an auto ecm work with my5 speed I heard it will just throw a check engine light

**Gojira94** · 07-22-2016

jthompson122183, lionelhutz

Great information, thanks for confirming. I had wondered why you couldn't just add the PWM programming into a 94 bin. It totally makes sense since the calibration ID determines whether or not the tables even exist for PWM. Like writing data into a region of the chip that the calibration never intends to read.

So... I think I'm done with doing anything else with this tuner in the mail order realm. I have reputable dyno tune outfits nearby if I go any further with this car. In the meantime I need to find a calibration for a 95 Formula that has the transmission performance button and 2.73 gears and simply do a few things I know how to do already in TunerPro. Maybe study the spark advance tables my tuner did and see if they are of any real benefit. If I'd known 5 years ago what I know now, I'd have done all this myself and saved 175.00 for the mail order and 75.00 for the '95 reflash.'

I just want the transmission problem gone so I can do the one other thing I want to do with this car- change gears to 3.42. I'm putting 4.10s in my M6 and planned to put the 3.42s in the car, using a ring spacer for the 2-series carrier. Which gives rise to the next question, which I can take to a different thread perhaps: I know how to change the speedo stuff, but what about the shift points? Is that all TPS vs. VSS vs. RPM? Do I need to account for the gear change elsewhere in the tune?

**Gojira94** · 07-23-2016

I pulled calibration ID EE_16210041 from Steve O's site (thanks, Steve). I made some edits to compensate for the O2 relocation with headers per TunerPro suggestion, desensitized the knock sensor a bit since I have a factory KM (probably unnecessary since I have headers but still have factory stamped steel rocerks at the moment), turned off and disabled AIR and EGR. I didn't do anything with timing at this point. I think this should be good enough to load into my PCM and see if the PWM stuff works like it should and the DTC 84 goes away once and for all. Modded bin and log attached. Thoughts/ opinions?

Thanks,

Rob B

**Gojira94** · 07-23-2016

I tried loading the modded 95 bin using C.A.T.S. I purchased about a year ago for my M6 car. I can read vehicle info, read and save old bin. I try to program the PCM and Establishing communications part is fine, fans kick on for 2-3 seconds as normal. When it then starts the 'erasing PCM' part, it fails after about 1 second with the message "Error: Invalid response from PCM"

So I thought maybe PCM says "I'm 94. No 95 programming for me." I changed the VIN year character from R to S and the "Current Model No." from 16202131 to the same as the one for the bin I'm trying to load, 16210041. That didn't change anything. Same error after repeated attempts with different combinations of KOEO, plug in cable, start winflash program , etc.

Will try EEHack next?

**Gojira94** · 07-23-2016

Using $EEHack on XP SP3 (unsupported, I know, but only laptop I have with a COM port). Stability test completes without any problems. Failed to upload new bin.

Applying VPP (EEPROM Programming) voltage
Failed to upload program to apply VPP HI voltage

(?)

This car is a stubborn little piglet. And I'm probably doing something incorrectly.

**Gojira94** · 07-23-2016

So from reading up on VPP here and there, it looks like a clue may be in battery voltage. I read that VPP can be 21V, 25V, 12.5V, perhaps others. The battery I was using had dropped to about 11.6V from all the KOEO fuel pump priming, so I grabbed the identical battery from my recently acquired 92 TBI truck (next project). It initially read 12.32V. After having some connection problems again getting sufficient power to the 12V input for the aldl cable (getting tired of fiddling with that), I was down to about 11.92V. So is my issue that the PCM doesn't see enough voltage to safely go into programming mode and fails the VPP check subroutine? My only other thought is to try another PCM. I have a spare about 10 miles away. I feel so close to finally solving this car's problem I can hardly stand it. Like 4th and goal, inches to go...

**steveo** · 07-24-2016

you'll definitely need a high enough voltage at the ECM to program.

1994 and 1995 program exactly the same, so that's not the issue.

you need to be really careful, this is probably a warning sign. continuing might mean bricking your ecm if you have unstable power.

what kind of aldl cable are you using that still needs 12v input? that might be a contributing factor? it's 2016, get a usb one already...

**Gojira94** · 07-24-2016

Originally Posted by steveo

you'll definitely need a high enough voltage at the ECM to program.

1994 and 1995 program exactly the same, so that's not the issue.

you need to be really careful, this is probably a warning sign. continuing might mean bricking your ecm if you have unstable power.

what kind of aldl cable are you using that still needs 12v input? that might be a contributing factor? it's 2016, get a usb one already...

Thanks for the insight. I don't have an RS-232 to USB with an FTDI chip but I'm considering another ALDL cable. Before I ran out of time yesterday I hooked up a charger to supplement the battery voltage and connected a meter to the leads on the 12V lighter outlet to monitor voltage. I was getting between 12.25-12.35V before that. After, I was getting about 12.72. The courtesy lights and door dinger and radio display (even when off) were droping it to 12.55-12.60V. The fuel pump and fans cycling dropped it below 12.4V in a hurry. So I tried pulling the fan relays and fuses for radio and courtesy. Fuel pump alone was enough to drop it to 12.45 when it cycled. Next, I'm headed back out to disconnect the fuel pump relay so I have nothing but the ALDL 12V and PCM draw on the system to see where that lands voltage-wise. If that doesn't cut it, I guess I'll be building a bench to flash my PCM. Funny thing is I have zero issues with my M6 car and its battery isn't quite as strong as the one in this car that I borrowed from the truck Tempting to flash it in that car...