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Tuning Issues, 04 GT (L32 Swap / Gear Swap)

RivMan

RivMan

New member
Hey guys, I can't seem to figure out this issue, and it's driving me nuts!

I've been driving my 04 GT for 9 months / 16k miles. Here's my current setup:

04 Grand Prix GT
04 CompG Motor
04 CompG 3.29 Trans (Valve body / Channel Plate replaced with GT parts)
04 CompG Harness (Modified to connect to the GT EBTCM)
04 GTP Base OS, 04 CompG Trans Tables
04 GT EBTCM (Stock for this car)

This setup works 95% perfectly, and I've put 16k on the car in the last 9 months. The only existing issue is that the 04 GTP has a different EBTCM then the GT, and this is causing the TCS to be disabled. Not a big deal, but I'd like to get the car to 100% functional.

I've been trying to build a tune based on an 04 GT base OS, with 04 GTP Engine tables, and 04 CompG Trans tables. I thought I had it right, TCS working properly, car was running perfect. After about 3 miles of easy driving (Sub 40mph, low load) I got into the throttle a bit. At around 50mph it felt like the trans shifted to neutral, then the engine stalled. After I coasted to a stop, the engine would crank, sputter, but wouldn't start. I waited 2 mins, and it started and ran just fine. I drove a couple more miles, and it ran / shifted great until I got over 50, under higher load, then it died again exactly the same way. I re-flashed my old code, and it drove fine for 50+ miles. I tried the new cal again, and it did the exact same thing after a few miles.

Any ideas? I've never heard of this issue before, and my setup is basically a Top Swap with 3.29 gears.

The new Cal I'm trying to use is an 04 GT base tune, with every table (Accessible from TinyTuner) from my current perfectly running tune copied over.

Thanks!
-Rob
 


the compg trans is way different.. I cant offer much other than these things.

1. The settings for trans stuff in DHP and tinytuner is sometimes completely broken for 04 files. Tinytuner has a few trans tables unlocked essential for swapping around gear ratios as well.

2. The compg trans may be completely different mechanically to the point you want to double check wiring and swap to a compg PCM or swap to a compg pcm.

3. There is no such thing as "gtp engine tables". All you should have for "engine tables" is some PE tweaks and injectors changed. You should also be using a 1bar map sensor.
 
Thanks for the reply!

1: Yeah, I've noticed that the 04 tables are pretty buggy in TinyTuner (Worse in PowerTuner). I was able to modify a stock GTP cal to run the 3.29's though, so I think I've got everything I need there.

2: I talked to Dave at TEP quite a bit when I was swapping this trans in. I changed out everything "Controls" related, so essentially the trans is a Non CompG spec 4T65E-HD with a beefier First Gear band, and 3.29 gears. I've been running it 16k miles using a slightly modified GTP code base, so I'm pretty sure it's functioning as I intend it to.

3: Poking around through the Fuel and Spark cal's between an SC car and an NA car, I see a ton of differences. Is there a reason to use a 1 bar over a GTP 2 bar sensor? Do you have a functioning 04 top swap file you could send over to me?

Thanks
-Rob
 
You can't change anything mechanically with maf sensors. If you have gtp code you need 2bars configured or deleted entirely. If you have a gt file you need to disable the map sensors or run it to the non boosted side of the blower.
 


Honestly, I don't like the idea of running without the ECU having a boost measurement. There are a ton of differences between a GT and GTP Cal. I've seen first hand the millions of hours of calibration work put into these cars, and I would like to keep mine as intact as possible.

-Rob
 
Stock GTP with 2-bar MAP = The ECU knows the current boost pressure, and can compensate for it.
Top Swap with MAP on the unboosted side = The ECU does not know the current boost pressure, and cannot compensate for it.

I don't like the idea of running the car in the second method.

-Rob
 
ECU knows the current boost pressure, and can compensate for it.
Click to expand...

I can promise you the ecu doesnt "compensate" for it. I run my 2bar car at 3 bar worth of boost without issues, and have setup more than a few cars without map sensors. Even if you told the ecu to "compensate for boost" its completely illogical to calculate anything off a map sensor when you have a MAF sensor.

Have fun with a broken car with the answer sitting right in front of you.
 
MAP sensors are used for more then a MAF can tell you.

One example, Injectors will flow less fuel as boost increases (Pressure differential between the Fuel Rail and Manifold decreases). The ECU will increase IPW to compensate.

I write engine control software for a living, it's easy to make an engine run ok under most conditions, it's tough to make it run right under all conditions.

-Rob
 


RivMan said:
MAP sensors are used for more then a MAF can tell you.

One example, Injectors will flow less fuel as boost increases (Pressure differential between the Fuel Rail and Manifold decreases). The ECU will increase IPW to compensate.

I write engine control software for a living, it's easy to make an engine run ok under most conditions, it's tough to make it run right under all conditions.

-Rob
Click to expand...

Its not nearly measurable enough to not compensate elsewhere if you cared enough to even compensate for it. The inaccuracy of the maf sensor is significantly higher than any flow rate difference you find at 10psi of intake pressure.
 
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