C41977

My friends 92 starting acting up recently so we changed ECU (it was either that or the distributor) and the car runs great, problem solved. However, now the speedometer doesn't work nor does the odometer and also the dash info. regarding the fuel milage and such. The ECU is a Delco unit....we ran the factory numbers, called the dealer and he gace us a GM part number which he crossed to a Delco number....everything else is fine. I put a OTC scanner on and the VSS reads MPH as you are going down the road so that would lead me to believe the VSS is OK...just somewhere it's not getting to the cluster. Any help would be appreciated.

engle1147

What type of problem did you have before the ECM swap? I know on the early 90's the cluster does/stores the odometer....I think on 94-96 the car's BCM does/stores the milage. Did you disconnect the battery before you installed the "new" ECM? Well you seem pretty sure that you have the right ECM back in there....not sure if that ECM needs to be flashed before install. So I'd check your fuses in the panel and all the connections that you may have disturbed during your ECM swap. Other than that you may want to strongly think about picking up a FSM (Factory Service Manual) for your car.

There's a guy selling a set in the C4 parts section....I bet if you sweet talk him he'll sell to you for $75 shipped. Here's a link: http://forums.corvetteforum.com/c4-p...e-manuals.html

Nathan Plemons

The mileage on a 92 is not stored in the ECM. Did you take the memcal out of the old ECM? I can't imagine that it would run without it, but it never hurts to check.

Bedo

I got my ECM rebuilt for my 92 awhile ago from SIA and my car has the same symptoms. I read elsewhere to just send it back and they can fix it. I had called SIA and they said to just send it back(its under a 1 year warranty) and they could fix it(by the sound of it, they have previous experience with the problem).

That being said, if its a fixable problem inside of the ECM, then the problem may be the ECM itself.

Thats all I can offer..Good luck.

C41977

Thanks for the responses...ok, the symptoms were just like the dist. going out....run fine then BAM, would barely run....had to pull over...then would run OK again for a day or so...I thought for sure it was the dist. even though the previous owner had just put a new one in. However, the ECU fixed it. The ECU had a TPIS custom chip in it. I called TPIS just for a little advice and he just said there's no way the chip has anything to do with it. I did disconnect the battery when installing the ECU and I am a big believer in doing so anytime you work on a car. As far as the flashing goes, I never thought about it. And most cars in my experience won't even run if the ECU is not flashed. I'm going to call the store I got the ECU from and see if they can get me another one. Or buy a used one and throw it in and see what happens. Thanks and keep the replies coming.

C41977

Bedo, what are u going to do next? Have u talked back with the company that rebuilt your ECU?

gw962

Your speedo and odo are controlled by the CCM. You can check this through your ALDL. Not sure on a '92, but my '90 is A - G. Any codes should show in the speedo display.
There is a possibility that the new ECU is not communicating with the CCM. If so, the codes will tell you.
Try this link : http://forums.corvetteforum.com/c4-t...ing-codes.html

Jim Martley2

C41977,

If you are anywhere close to the Albany, NY area I have an ECU that you could try swapping out.

Jim