100% pedal position but never get more than 35% tps and

[Covert1]

I've got a custom jeep rock crawler with an LS3 430 hp crate, 480 HP controller on, 6l90E trans, Atlas transfer, 5.39 gears, 42" tires. It's been tuned but we're having an issue with it coming off idle. If you floor this thing it will barley pull out of it's own way for the first 30 yards then it starts gaining momentum. We tried a bunch of different stuff with spark, throttle settings, etc but nothing seems to change it. There are no codes. If you floor it the pedal position shows 87-95% but the tps nred jeep no throttle.hplLS Jeep - ECM and TCM Tuned - Throttle-3.hptred jeep bad throttle signal.hplred jeep throttle sweeps.hplever goes above about 35% and the commanded TAC is the same. Anyone have any insight ass to what might be causing this.

[blindsquirrel]

I am preeeety sure that even though that ECM and that TCM will both talk to the data link connector and both can be read/written, they are not actually talking to each other. The GMPP/CPP ECMs are for manual trans, or non-electronic auto, or standalone auto with a separate controller. They don't turn into auto trans ECMs just because you plug them into a harness that happens to be shared with a T43/T42.

[blindsquirrel]

24254909 is 2010 CTS-V, correct?

[Covert1]

24254909 is 2010 CTS-V, correct?

I'm not sure on the OS. The transmission does respond to changes in the tune in the ECM. The ECM was segment swapped in the current setup. I fought a ECM/TCM comm error code for a minute in this thing. Put a new GM harness in from trans to ecm and the code went away after a write entire on both with the current tune. I know that usually the 6l80-90E uses it's own controller but the trans does respond to changes in the tune but was wondering if there may be comm issues causing the TAC not to open. As the rig accelerates it will start to open the throttle more. It's just off the line where it doesn't rise above 35% or so.

[Covert1]

I am preeeety sure that even though that ECM and that TCM will both talk to the data link connector and both can be read/written, they are not actually talking to each other. The GMPP/CPP ECMs are for manual trans, or non-electronic auto, or standalone auto with a separate controller. They don't turn into auto trans ECMs just because you plug them into a harness that happens to be shared with a T43/T42.

I think the easiest fix is going to be buying the stand alone unit from GM to fix it.

[Covert1]

With the throttle control axis set to RPM not VSS would it matter as far as throttle control goes?

[Alvin]

I've got a custom jeep rock crawler with an LS3 430 hp crate, 480 HP controller on, 6l90E trans, Atlas transfer, 5.39 gears, 42" tires. It's been tuned but we're having an issue with it coming off idle. If you floor this thing it will barley pull out of it's own way for the first 30 yards then it starts gaining momentum. We tried a bunch of different stuff with spark, throttle settings, etc but nothing seems to change it. There are no codes. If you floor it the pedal position shows 87-95% but the tps nred jeep no throttle.hplLS Jeep - ECM and TCM Tuned - Throttle-3.hptred jeep bad throttle signal.hplred jeep throttle sweeps.hplever goes above about 35% and the commanded TAC is the same. Anyone have any insight ass to what might be causing this.

This looks like BTM to me.

You should have been instructed to hook up a brake wire when doing the GMPP kit. Double check instructions wiring.. in the meantime this might give you a work around.

LS Jeep - ECM and TCM Tuned - Throttle-3 alvin.hpt

[blindsquirrel]

The transmission does respond to changes in the tune in the ECM.

No because it doesn't work that way. A '.hpt' file is an ECM file and a TCM file combined into one thing. Changes you make to the Transmission side of things get applied to the TCM. You're writing two separate controllers. None of any of that means the ECM and TCM are able to talk to each other. The production-car TCM is talking, but the manual-only ECM isn't listening because it's got a manual operating system in it still.

The ECM was segment swapped in the current setup.

I do not believe that is an accurate statement. No GM production car ECM segments have IDs of '0'.

screenshot.15-05-2024 15.02.00.png

[Alvin]

No because it doesn't work that way. A '.hpt' file is an ECM file and a TCM file combined into one thing. Changes you make to the Transmission side of things get applied to the TCM. You're writing two separate controllers. None of any of that means the ECM and TCM are able to talk to each other. The production-car TCM is talking, but the manual-only ECM isn't listening because it's got a manual operating system in it still.



I do not believe that is an accurate statement. No GM production car ECM segments have IDs of '0'.

screenshot.15-05-2024 15.02.00.png

I'm not certain but this looks like the newish GMPP LS3 kit with a 6l80.. It comes with stand alone software for the T43 but it will read and somewhat work with HPtuners. In those setup/files the ECM still says MANUAL.

[Covert1]

This looks like BTM to me.

You should have been instructed to hook up a brake wire when doing the GMPP kit. Double check instructions wiring.. in the meantime this might give you a work around.

LS Jeep - ECM and TCM Tuned - Throttle-3 alvin.hpt

"the required connections for trans operation are,Chevy perf engine wiring harness and the output speed sensor(VSS). All other connections are not required to be used but can be used to increase functionality" From the installation instructions. However, I do agree with you that it needs hooked up. See above post for more info.

[Covert1]

Let me be more specific on the situation i have going on. This is a $450K custom jeep rock crawler that was built by several different shops in Utah, Washington and Cali before it graced my door. The first time the owner drove it, he made it 1 mile up a trail in Moab and it caught on fire. Burned up the engine harness. It sat for a year before he found me. The engine is the 430 HP LS3, they installed a 480 HP LS3 controller and harness, The jeep was shipped to Hughes transmission and they built and installed the 6l90E, it was then shipped to Vegas and someone there was supposed to "Tune" the engine and transmission together. I don't know exactly what happened there. When i got it there was an extra wiring harness under the jeep coming off the transmission with a 7 or 9 pin connector that i had never seen before or since. I couldn't find a wiring diagram anywhere on the internet, alldata or prodemand that matched any of the wiring in this jeep. We repaired the harness that had burned up, repalced the harness from the trans to the ecm with a GM one and took a box full of wiring out of the jeep. I have used Mitch "Kiwi" Duncan for my tuning for years and he has never failed me yet but i can't get ahold of him currently and this jeep is supposed to leave for Moab Friday. From what i had gathered from him, he had segment swapped the trans control into the ECM. The throttle on this jeep has been this way since i first laid hands on it. I'm trying to figure out if i purchase the GM trans controller and harness then will i still be fighting the no throttle responce issue. The jeep is coming back after this Moab trip for a TVS2650 SC and intercooler system. The owner was just here and after talking to him the plan is were going to order the GM 6l90e stand alone controller and harness, a new engine harness and install all of that when we do the supercharger. As far as the tune goes Alvin, i have your work around installing right now to see if it works. Thank you both for the help. If i can figure out a way to get it to work for this trip that would be great. The Jeep is something else.

[Covert1]

I haven't hooked it up becasue it was at the bottom of my shit that needs done list with this thing. LOL.

[Covert1]

I'm not certain but this looks like the newish GMPP LS3 kit with a 6l80.. It comes with stand alone software for the T43 but it will read and somewhat work with HPtuners. In those setup/files the ECM still says MANUAL.

Alvin, whatever you changed made a big difference in the throttle response from a stop. It still didn't look like it was going over 38% though. Here's a log from that short run. Most of it was WOT.jeep throttle better.hpl

[edcmat-l1]

It's going 100% wide open now. You have way too many throttle position pids and some of them are incorrect.

You aren't logging any trans pids so if it still feels like a dog it might be in the wrong gear.

Also the timing tanks at peak torque. That's not helping it any.

[Alvin]

Alvin, whatever you changed made a big difference in the throttle response from a stop. It still didn't look like it was going over 38% though. Here's a log from that short run. Most of it was WOT.jeep throttle better.hpl

It's going full throttle now.


Look into the GMPP catalog for the crate engine + 6l80 setups. The "stand alone" controller isn't one like you would think. It's not a separate box or anything.. its a simple harness like you describe that goes from the trans connector to the GMPP connector.

The odd thing about these are... HPtuners will read the 6l80 and you can do some tuning in there on them.. but it doesn't all work. Basically only expect to make shift pattern changes.. no shift pressure/time changes. The TCC on these kits are either completely locked or not which is uncomfortable and not much you can do to change it. That kit comes with a separate cable and software I think PCS makes it for GM