i got a new ECM and it is getting power from the orange wire. the only place i am picking up any voltage is the white/green(i think) wire for the check engine light and power to the TCC. do i have a bad PROM?

 

Testing voltage from the ECM is a tough way to diagnose, easier and more effective to use the Helms procedure to diagnose ECM or PROM problems...do you get Code 12 with ALDL pins A&B jumped? If not, and you're sure you have no ground problems, you're down to either the ECM or PROM.

 

no codes at all. the light comes on and stays on.

 

No clue if this works for an '84, but for an '88 you would now disconnect the ECM completely and put the key in <RUN>. If the Check Engine light comes on, you have a short in circuit 419. If the Check Eng light doesn't come on, you'd replace the ECM and re-test, then the MEMCAL and re-test.

Again, this is for an '88 TPI car and I don't have a manual for an '84 so may not even work on yours.

 

Whatever happened with this deal? I am experiencing the same problem with the SD TPI in my Jeep . At first I though It was just a bad 29C256 but I have tried another one and tried the original prom that came in the memcal and I still have a Check engine light. My scanner won't communicate and I tried jumping pins A and B at the ALDL and it just stays on. Does not flash. I even tried the ECM out of my Corvette and I get the same thing. I am using Moates adapter in both. At first it was an intermittent problem now it just stays on no matter what. It will run just not real well. If I unplug the ECM the light goes out. Any suggestions? Also when the problem was only happening of and on before, the light would go out all of the sudden while driving and I could read the codes and it gave me a Prom Error.