85 Corvette digital dash going haywire!
Thread Starter
1st Gear
Joined: Oct 2011
Posts: 1
Likes: 0
From: Osawatomie Kansas
85 Corvette digital dash going haywire!
I have a stock 85 corvette with the only modification being a HyperTech chip. Sometimes it wouldnt run worth a hoot and the check engine light would flash very rapidly. It had a code that said Cal-pack missing. I thought that either the calibration pack was bad or the PROM. So i got ahold of a used PCM that had the PROM and Cal-pack in it and changed the whole thing out in my car. It ran great for about a week. Then one day i got in it and as soon as i started the car the guages went completely haywire. Now, while driving or sitting, with the engine running the guages all go back and forth from there toggle positions. Example, MPH to KmH, oil psi to oil temp, full to empty (fuel) rpms x 10 or 100. It sits there and all this is going on so fast its hard to even comprehend whats happening. So i pulled the other pcm out and swapped the Cal-pack and prom to my original PCM, sam thing AND the engine ran like before. I then put my ORIGINAL prom and Cal-pack in the "new" PCM. Car ran fine but the guages were still freaking out. The used PCM came out of an identical vette. Thank you in advance!
