1990 GP Speedo/Display HELP!!!!

I know Pontiac had many issues with their main gauge display(STD one) and about 10 years ago mine was replaced by GM because of the check gauges light staying on for no reason. Over the past few years the speedo does not read with any consistacy reading high some times and low others and the fuel gauge reads no where near correct. Now I have not done any trouble shooting on the fuel gauge to see if it is a related problem as the speedo because I have been mainly looking at the speedo for now.

Here is what I looked at so far, I checked out the speedo drive, and all the wiring and conections from the display to the drive to the ecm, I even changed the ecm because I had an extra one laying around from a car 2 years newer. I have a feeling I'm running in circles and the problem with that display again !!

Has many other people seen this also ?

Fire,

Sorry I cant help you, I have no idea.

Try going over to www.clubgp.com they have a pre 97 gen forum and many pre 97 owners that might have an answer for you.

Tim

Bump....I have the same problem...My check gauges and low fuel light are always on too but I know how to fix that one now. Speedo is just plain crazy sometimes. I also have problems with the cars idle. Anyone think these gauges might have something to do with it. I'll be sure to post again once I get everything fixed

fire, 90-93 grand prix inctrument clusters are notoriously inaccurate. the speedo problem is not uncommon. the fuel gauge is probably due to a bad sending unit. i have the same problem with my 90, but i'm too lazy to change it out.

if you're worried about inaccurate speed, i would suggest swapping in a new cluster. or, if you're up for a little extra work, retro fit a cutlass supreme digital cluster into the grand prix cluster housing. that'll take car of the accuracy problem with the speedo.