why wont a GTP pcm work in a GT ? 1999

[jaybur]

I am trying to get performance shifting ability in my 99 GT. and since the tuner does not have the option to turn it ON at this point, I thought if I put in a GTP pcm and just edited the tables to be exactly like the stock GT tables it would be good to go.

but no worky.

I had the "compare" feature on and went over everything possible and made it the same (even the dtc's), disabled the VATS just in case that was it.

it will crank, but it will NOT start.

it is a GTP pcm out of a 1999 gtp, going into my 1999 GT.

when the GTP pcm is installed I can see the "boost" gauge light up in my DIC.
Also on the scanner table, I can see the performance shift feature turn on and off.

it just won't start.

any ideas, or have I just wasted time and money on this GTP pcm?

[bilemke]

Ahh.. Here you are (I noticed your post in CGP).. Post your hpt file and I will see what I can do.

[jaybur]

do you want my stock GT file or the GTP file ? just want to make sure you get the right one

[bilemke]

Unless you are running a top swap, l67 in general or a turbo, use/post the GT file. Not worth using the GTP file for a non-boosted GT.

[jaybur]

ok here is my stock GT tune

[02bluegt]

Try unplugging the MAP, it is a different sensor GT vs GTP, and may cause issues, also there are some areas of the trans that cannot be tuned by hpt, and you will have odd shifting......but if you find someone with a PT, they can turn on the Perf shift in the pcm for you

[jaybur]

yea I know someone with a PT can turn it on. but I have HPT ! If I knew someone with a PT I probably would have just paid them a few $$ to tune my car and been done.

it should have been an option right off the bat, but apparently they are working on it in an upgrade.

[bilemke]

Geez.. No patience.

Attachment 15556

Should work with performance shift button just like a stock 99 GTP file now. Otherwise, stock file.

BTW, that is not the latest OS/cal update for your vin. There is 1 update beyond that from GM. It is something about fuel gauge accuracy. If you have the 99 GP mode/year licensed, let me know. I might be able to get you the updated calibration with the same performance shift change.

[jaybur]

thanks!!! I will be applying that to my pcm today.

and I do have open season on 1999 grand prix pcms (bought the year model license).

so if you are willing to do the upgrade I would appreciate it!


and about being impatient,
Its not that I don't believe they will ever make the upgrade to do do that with hptuners software, but I just have a feeling its not at the top of there list.......

[bilemke]

Was just joking on the "patience" thing.

Since you have the 99 model/year lincense, I will see if I can grab that updated calibration for your vin.

I am betting HPT will get to the setting.. It is just such a small setting, adding it may not be a high priority. You basically turn it on, and then it is done. No need to "tune" it, so the need to edit it more then once is unlikely. I think I remember seeing them offer to have people send files to them to turn it on. Since I am able to do the same, I offer to do it for you guys that post this question over and over again.

[jaybur]

well I really do appreciate it.

most people probably don't care to have perf and normal shift, they just want the better shift points all the time. But I really want an economy and a FUN setting, so it is a big deal to me.

other than the lack of the ability to turn that setting "on" I really do like the tuner. Although I am still a "newbie" to the tuning scene.

[robfromlouisville]

i have a top swap l36 gt i do not tune the performance shift.. all my tuning is done under normal shift .. if you have a gp gt y tune the peformance shift when you dont have the button to turn it on? i dont think it will do you any good because with out the button how r u going to get the pcm to go from normal to performance,to read the tables.

[jaybur]

actually I have a GTP shift knob, and I put the necessary PIN in the PCM harness with a wire going to the performance shift button.

I now have performance shift in my GT (thanks to bilemke) and it works like it should!

the light on my digital information display come on when I push the button, and the one on the cluster ( I made that part work too)

[bilemke]

Yeah, it is quite easy to install the knob with button, wire and pin in the PCM. I think I noticed knobs out there for like 10-20$ on ebay in the past. I might be buying one for my sister with a 2002 GP GT. For the little bit of $$, I still wonder why GM got rid of it in 01-03 GPs.

I do the same thing with my settings.. I dont want to compromise by having only one set of settings for all conditions. My normal shift settings are much lower and a bit softer. Better for MPG and nice for driving around with passengers that dont care for the harder shifts. When I really want to move, I just flip the switch and go back to the higher shift points and engine revs.

[jaybur]

from what I hear the "stock" gtp normal to performance is not much different. so just to use it as a stock setup would be a waste of time and money.

but I have a pretty radical difference between normal and performance.

also for me, I live in a mountainous area, and having the better shift points will be a big benefit. Normally the trans is constantly shifting due to how the road is, flat then hilly, flat then hilly. so it at times can go from 3rd TC locked to 1st gear. with higher shift points it will stay in 2nd more often, and give my tranny a break.

but cruising on the highway or like you said, with passengers who wouldn't care for the sharper shifts, just click a button and its a nice normal style shift.

THAT is my I wanted it so bad, and thanks again!

[bilemke]

I will see if I can find a copy of that other OS id for you this weekend. Otherwise, I have a 5 day weekend starting on Turkey day.

[jaybur]

cool, no pressure, (why would I when you are helping me).

[bilemke]

Alright, see attached..

Newer stock cal, again with performance shift enabled.

Attachment 15616

[jaybur]

thanks again!