I am asking for a buddy with a 1993 Corvette. He wants to know how to determine if an ECM is good or bad? Any test he can perform?
Thanks in advance

 

The easiest way if your lookin for a "slam dunk" ecm failure is to remove the ecm from the bracket, disconnect it, and remove the circiut board from the case. look at the board for a brown mark/black burn underneath the plastic coating. Thats the only way I ever knew how to see if they were bad. ecms dont usually go bad, but when they do most of the time the board will show it. Ive only seen this about 3 times in the last 10 years.

if it looks good, put it back together making sure it seals up right.
its easy to do and only takes a few minutes. all you need is a small torx bit.

I hope this helps you!

 

Hello,
I have a 93 and I've worked on the car quite a bit. I have used Datamaster on it and meters and other test equipment. The ECM has so many functions that it would be hard to give any kind of intelligent answer or advice without knowing what is happening with the car.

If you can find a printout of the ECM inputs and outputs you may be able to make a better judgement on whether it the ECM at fault.

It has several fuses, several grounds and several input power points.
It has coolant temp sensor, oil temp sensor, throttle position, O2 sensor, input air temp and others. The ecm has probably near 100 wires plugged into it.

I have found a few electrical problems with this car in the last couple years and everyone was found to be what I call real world problems.
Broken sensors, burnt wires, dirty connections, loose connections,
water damage and somebody messing with something before I bought the car.

So far the ECM has been fine through all this. I'm gonna guess that dealers replace a lot of ECM's that are fine.

The 93 does have a quirk about it when it comes to downloading its internal data with datamaster, I think it sometimes loses some stuff.

Does the car start? Does it run? Any alarms?

Hope this helps.

 

According to him he had
to bypass the starter relay and fuel pump relay to get vette started . He was wondering if the due to ECM failure.

 

Find someone with a "good" ECM and switch it out. Probably the best / easy test for it.

 

That is the best idea I ever heard.

Fuel pump relay and starter relay bypass, that sounds like it MIGHT? be the Vats key?