E67 PCM Issues

[The Shop Inc]

07 Trailblazer ECM and tune. Car is a 1955 Chevy with an LS3.
Engine/trans and harness and original tune came from Street and Performance. They use LS1 edit so I could not tune existing file. So I started with a stock trailblazer tune and ecm.
Here is my problem. #1. If you very slowly press the gas pedal, it will start to count up on ETC Pedal position and the idle will be stable at around 12% ETC position. As soon is Pedal position gets 6-7% the ETC position drops to 7% and engine stumbles and sometimes dies. If you keep pressing pedal and get to 8-9% it comes back to normal.
#2 When accelerating in neutral and letting off the ETC position drops super low and engine stumbles. Then will count back up. If in Gear and power braking a little then letting off it dies every time.
I have tried and tried to solve this and am at a brick wall.
Any help would be greatly appreciated.
The log will show both conditions. #1 at first then #2

[DSteck]

Is the LS3 stock? Or do you have an aftermarket cam in it?

[The Shop Inc]

Has a cam in it. No idea on specs.

[DSteck]

There's the brunt of your problem. Raise idle a bit, raise final idle airflow, and add a little idle timing.

[The Shop Inc]

Ive done that. It idles at 875. Idles very well. The problem is the actual throttle blade shuts. I cant find the airflow tables that will fix it.
I have tried everything I can think of with the airflow final tbl. throttle follower tbls. and Proportional and Integral tbls.

[The Shop Inc]

Anyone???

[The Shop Inc]

It doesn't seem to do it when first starting and the engine is warming up. Its nice and smooth.

[The Shop Inc]

Ttt

[HRD]

Here's the GMPP tune from an LS376 with the GM "hot cam" We put this crate engine in a 65 Corvette and it runs very well right out of the box. Haven't changed a thing.
Hope that helps.

[96LT4C4]

I think I have this car sitting in my garage. Trying to tune it.

[castorjames]

...

[96LT4C4]

The car I am working on is a 1955 Chevy, LS3, with a TBSS computer and a 4L60E. Its a show car that the owner bought years ago. The car has $200K invested it, but ran like crap. The owner didn't care, as long is it would drive in and out of a trailer to shows, thats all he cared about. Now the car is for sale and he wants it running right. Two local shops have had the car and not been able to do anything with it. So, it ends up in my lap with a tuner locked ECM. The car is a complete mess, as far as the tune goes. I have swapped the ECM and now I can at least read/write the car. After I swapped the ECM and re-flashed a good TBSS tune, the car would start and die. Thats where I am at.

Anyway I found this old post by searching. Thought it was interesting that I find a post with a 1955 Chevy with the same odd engine, ECM, trans, combination.

[Jon S.]

... After I swapped the ECM and re-flashed a good TBSS tune, the car would start and die. Thats where I am at. ...

Did you initially flash the replacement E67 ECM using GM software ?

[96LT4C4]

Did you initially flash the replacement E67 ECM using GM software ?

No I did not, but I was able to fix it by disabling the VATS via the VATS 1 and 2 patch. The car will start and run great now, but now I am getting P0606 ECM/PCM Processor.

The original ECM was from a TBSS with an LS2, but was locked. The new ECM was from a TB with a 4.2, licenced that file, then licenced a new TBSS file from the repository to flash into the new ECM. It took the flash but came up with a garbled VIN which gave me an unlicenced vehicle message, so 2 more credits to licence it. Six credits later, I can read/flash the car, it starts, idles, runs great, but now when I drive it, at about half throttle it will throw the P0606 and goes limp home, with no throttle input from the pedal. Clear the code, restart the car and its good till the next time. I have read that it has the do with the ETC settings but I have not messed with them. I have also read that the E67 is hard coded to the pedal and TBI combination it came with? This poor guy has been rolled over the coals with this car and I would really like to get it fixed for him.

[Jon S.]

I always empathize with such tales of woe. Good job on your part so far.

With the older Gen 3 PCMs (P01, P59, etc.) you could use tuning software to fully reprogram the controller. With the later controllers (like the E67 ECM) tuning software by default, only programs 6 of the 8 segments within the E67.

Unless the replacement E67 is from a V8 Trailblazer, then you will have throttle control issues - unless you use GM software to initially fully reprogram the ECM.

Most of the time this type of “partial” reprogramming (using tuning software) will leave you with no throttle control whatsoever. In your case the I6 and V8 Trailblazer used the same APP (accelerator pedal), but different throttle bodies. So the APP diagnostics will “pass”, giving some initial throttle control, but eventually the throttle diagnostics will “fail” - causing limp mode.

In your specific case, the P0606 code is an indicator that the throttle programming is incompatible. Also, a reflash that corrupts the VIN (actually corrupts the VRAM) is indicative of incompatibility issues.

[96LT4C4]

I always empathize with such tales of woe. Good job on your part so far.

With the older Gen 3 PCMs (P01, P59, etc.) you could use tuning software to fully reprogram the controller. With the later controllers (like the E67 ECM) tuning software by default, only programs 6 of the 8 segments within the E67.

Unless the replacement E67 is from a V8 Trailblazer, then you will have throttle control issues - unless you use GM software to initially fully reprogram the ECM.

Most of the time this type of “partial” reprogramming (using tuning software) will leave you with no throttle control whatsoever. In your case the I6 and V8 Trailblazer used the same APP (accelerator pedal), but different throttle bodies. So the APP diagnostics will “pass”, giving some initial throttle control, but eventually the throttle diagnostics will “fail” - causing limp mode.

In your specific case, the P0606 code is an indicator that the throttle programming is incompatible. Also, a reflash that corrupts the VIN (actually corrupts the VRAM) is indicative of incompatibility issues.

Wow...that figures. So what do you recommend I do? I either need to find a TBSS computer or have this one fixed with the GM software? What does that entail? I had something similar happen with a customer that turned the car off in the middle of me flashing. 08 C6 LS3, he got tired of hearing the door chime. We put an 08 Impala computer in the car, it took the flash and ran. It did garble the VIN but that was it. No other issues. This has been such a mess already, I may stray away from things like this in the future.

I have done several 411 LS1's like this in the past, like you said, and never had a problem.

[Jon S.]

The 2008 Impala and 2008 Corvette pedals (APP) are similar electronically, in your previous example, the diagnostics for each platform must have been sufficiently close as to not cause the diagnostics to fail.

With Gen 4 controllers, we initially program the ECM / TCM using GM software (ACDelco TDS) to avoid any possible issues with the throttle control (for reasons of liability). Given the changes (restrictions) to how this software (ACDelco TDS) may be used, this has become challenging from time to time.

Your best course of action would be to have the E67 programmed by someone with a Tech 2 / MDI and that has access to SPS or ACDelco TDS.

We don’t ship outside of Canada, so unless you are also from The Great White North, we cannot assist you directly.

[96LT4C4]

The 2008 Impala and 2008 Corvette pedals (APP) are similar electronically, in your previous example, the diagnostics for each platform must have been sufficiently close as to not cause the diagnostics to fail.

With Gen 4 controllers, we initially program the ECM / TCM using GM software (ACDelco TDS) to avoid any possible issues with the throttle control (for reasons of liability). Given the changes (restrictions) to how this software (ACDelco TDS) may be used, this has become challenging from time to time.

Your best course of action would be to have the E67 programmed by someone with a Tech 2 / MDI and that has access to SPS or ACDelco TDS.

We don’t ship outside of Canada, so unless you are also from The Great White North, we cannot assist you directly.

Thanks for all your help.

[schitzo]

No I did not, but I was able to fix it by disabling the VATS via the VATS 1 and 2 patch. The car will start and run great now, but now I am getting P0606 ECM/PCM Processor.

The original ECM was from a TBSS with an LS2, but was locked. The new ECM was from a TB with a 4.2, licenced that file, then licenced a new TBSS file from the repository to flash into the new ECM. It took the flash but came up with a garbled VIN which gave me an unlicenced vehicle message, so 2 more credits to licence it. Six credits later, I can read/flash the car, it starts, idles, runs great, but now when I drive it, at about half throttle it will throw the P0606 and goes limp home, with no throttle input from the pedal. Clear the code, restart the car and its good till the next time. I have read that it has the do with the ETC settings but I have not messed with them. I have also read that the E67 is hard coded to the pedal and TBI combination it came with? This poor guy has been rolled over the coals with this car and I would really like to get it fixed for him.

I had this exact issue; car would go into limp mode after a certain pedal % and throw P0606 code. The ECU was originally out of a 2012 Camaro and I had used HPTuners to write a tune from a 2012 Corvette. Apparently HPtuners does not write the throttle segment so the mismatch in tunes was causing the issue. I had a local place use GM software to write the Corvette tune and that fixed the issue. PM sent.

[jpierro79]

There’s a hptuners segment stating very specific about overwriting OS systems and writing different operating systems in different ecu’s especially writing e38 and e67 your going to spend more time chasing your tail unless you get the dealer to rewrite the ecu to its original state. The other issue is fuel pressure settings on e67. It could have variable pump turned on. My 2013 zl1 has e67 ecu so you might have the variable pump software in it. If you don’t find out your actual fuel pressure and if it’s not turned off your in for a whole lot of headaches. I doubt they wired in fpcm to 55 Chevy. Last is the maf re-enable under airflow/dynamic set real low cause this will really give you low throttle headaches cause a cammed car doesn’t have steady low rpm vacuum either. There’s a good reason gm set the maf rpm boundaries high. Low rpm is not anywhere near as accurate as a tuned VVE w map sensor. Basically speed density mode. Best of luck. I don’t like to tune cammed car as everyone is different and has it’s own headaches.