Speedometer.not working Bad ECM

Orange39
Thu, 26 Aug 2010 21:57:03 +0000
Maintenance/Repairs

I have a 1991 Buick Century Special 2.5L. The car had stalling problems when coming off the freeway or up to a stoplight after driving at highway speed for an extended time. The problem seemed to be ECM (computer) and I ruled out the Transmission and TCC. I changed the ECM along with the ignition control module and crank sensor and the car drove just fine without a check engine light. Then, the speedometer stopped working after a couple days and the check engine light came on. SO i took it to a mechanic and he tried a couple different ECMs and the speedometer would work but the stalling problem returned. So i put the “good” ECM back in and have been driving without a speedometer for a couple months now and the car has drove fine. My question is What causes my speedometer to work with one ecm and stall, and not work with the ecm that makes the car drive fine? What problem is actually occurring here?

Should I try yet another ECM?

3 posts - 2 participants