Need tech. help, engine breaks up at 5000 to6000 RPM

[vegasviper]

Any help would be great. Engine breaks up at 5000 to 6000RPM and seems to run better with check engine light(MAP low input)on. I replaced the MAP, TPS, grounded bat. sensor and TPS and no change. I swaped PCM from 99ACR to my 97 GTS and it seemed worse at the same RPM. I did notice shutting car off and starting again sometimes cures problem. Sometimes it takes 3 or 4 times starting and shutting engine off to cure RPM problem. The RPM break up only happens under WOT only, if i let off just a hair it RPM just fine.

Any help would be great.

 

[vegasviper]

Can it be my VEC2??????

 

[MbnViper]

hi, did u do the VEC2 upgrade ? swap cards! and drive test and see! im not so good but maybe u are running lean above 5000RPM! also check fuel injection harness are u using the MSD injector connectors ? i wish i can help more, but i never had any problems since i installed Roe S/C alone with Zero mechanic experience and as always contact Sean im sure he knows about his supercharger more than anyone else

 

[vegasviper]

Yes i am using MSD. Noticed that when brake up clears then if i turn car off and start again it happens all over again.
Seem like even if PCM learned to run great, it happens all over again when i restart car
.

 

[MbnViper]

maybe its a PCM issure, also using Mopar PCM with S/C is not recommended so i guess the swap didnt help,maybe its VEC2 wiring harness,or a BAD PCM

 

[vegasviper]

I tried 3 different PCMs, same problem

 

[JimDavis MT 97GTS 650R]

I had a similar issue a few years ago with my 97 GTS. I had the PCM "re-flashed" by the dealer. It solved the problem for me. This is done by downloading a factory computer program to your PCM, specifically designed for the problem. The program, TSB 18-32-97, was designed for 96 & 97 Gen II engines experiencing high speed break up at 5000 RPM. Hope this helps. You will want to stick with the 97 PCM, as the 99 unit has features such as "leak detection" which your car is not equipped with, and it will throw codes. (Jim Davis)

 

[JimDavis MT 97GTS 650R]

IMPORTANT NOTE!: I neglected to mention that this program (TSB 18-32-97) will efectively replace the Mopar performance program (if you are using a MoPar Performance PCM) with the revised "stock" program. This was no big deal to me as the car ran better with the stock program anyway, even with heavy mods.

 

[vegasviper]

Thanks jim, i will have it flashed.

So,18-32-97 is the same as Mopar PCM? also, is there one or two versions of Mopar PCM?

 

[JimDavis MT 97GTS 650R]

The revised program 18-32-97 is not the same as the MoPar Performance program. To my knowledge, no revised Performance program exists for the Performance PCM. The dealer does not even have the original Performance program to re-install should you wish. If you reflash the Performance PCM, you will essentially end up with a revised stock PCM. Hope this helps. (JD)

 

[Ulysses]

You're getting a check engine light? What are the codes?

 

[MbnViper]

vegasviper ? any news ? hope its working now ..did you contact Sean about this ?!

 

[vegasviper]

I still have the problem, and noticed that it goes away when i cycle the engine. Cant figure it out

 

[vegasviper]

codes are for low input MAP and for the first time today for emision