Diagnosing a PCM problem can be difficult.....

[Sean Roe]

Hi Everyone,

Just thought I'd share my two day ordeal in tracking down an unusual problem in a 2000 RT/10.

Last week we put a Supercharger on this car. However, I made the mistake of not taking the car for a drive before installing it and assumed the car was running properly.

The symptom that would occur was unusual. When the car was cold, it ran great. As it warmed up (after initially idling or driving for about 20 minutes), you could hear the car kind of "go off" on one cylinder. Also, if accelerating mildly in 5th or 6th, you could feel a stumble.

The car began setting a code for a misfire on cylinder #8. So, we started there, testing and changing spark plugs, then wires, then coil pack, then VEC2, then VEC2 harness, then battery, then system voltage until we finally found it.

It was the PCM. Fortunately, we had a 2000 PCM that we used for VEC2 programming and you could hear the car run differently as soon as we plugged it in and started it (ran smoother). I took the car out for a drive and it ran perfect with the used PCM (this PCM had a dealer re-flash # on it that we're checking out).

To verify, we then put back in the original PCM. The same symptoms reappeared. Though it did not set a check engine light on the drive, it did set a pending code that we were able to pull using the EASE software.

Hope this helps someone else who may run into this one day. It was no fun to find.

Sean

www.RoeRacing.com

 

[2MANYTOYS]

Thanks Sean for the info. Hopefully next week when mine is installed all will go smooth. It's good to know that you stuck with it until you tracked it down. That's real customer service.

 

[RockyTop]

Sean,

Would a reflash of the old PCM have solved it or was it more of a hardware issue ?

Rocky

 

[Bill/APEX Motorsports]

Interesting, because we went through the exact same scenario and parts-changing procedure (less the battery) on a '97 GTS. It was very frustrating, but very educational at the same time. Vipers aren't as "tell-tale" as some of the other performance cars we work on, and the scanner won't always help much.
Glad you found the problem, though, albeit with fewer hairs on your head afterward!!

 

[HP]

I think everyone appreciates the effort made to share an experience that,
in the rare likeliness of occurrence, could just push you over the edge.
If it's not posted - then others will be doomed to repeat your ordeal.
Myself, and others, rely on these archives for that purpose - and while
the written record will be there - you might be like that dude on the commercial that hits his head or has a stroke.