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

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

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

Hmm...

I may just have to track down a GTP EBTCM then.

Thanks
-Rob

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

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