ICM? PCM?
 

Hello,
I have a Fiero that I but a Series 1 3800 into. ran for a bit then it started do odd stuff. I have checked for melted wires and verified that all is good. I started to diagnose what is there. I have fuel but no spark. I started looking at what is going on. I have power to the ICM. on the 14 pin connector feeding the ICM I checked the voltage to the Cam and crank sensors. It is supposed to be 10 to 12 volts. I actually have 9 volts. The sensors are switching but they should be 5 or 6 volts and I am getting 8.66 to 0.13V. My thought is the ICM is bad. any thoughts from this group??

Thanks
J

How long did it run before acting up? What year is the car? What did the 3.8 come out of?

The engine came out of a 1995 Buick Ultra. It ran probably 50 miles just fine. I took it to get gas and to the grocery store twice. I live about 15 miles from anything so that means it was warmed up 3 times. It was idling fine but on acceleration it would backfire and then quit. I put a Bluetooth scanner on it and the scanner would be recognized but it would no read the computer.

I believe your car has the OBD2 connector, but an OBD1 system. 99% of today's OBD2 scanners can't communicate with OB1 systems. Actron has a scanner.. https://actron.com/content/elite-aut...d-ii-scan-tool

If it starts and runs good until it warms up, then develops these conditions, then I would start looking at the ICM.

Thanks, after I have been looking into the OBD2 connector it no longer runs. I get fuel but no spark. I just do not want to be a replacement artist. It appears that the ICM is a problem. I am getting pulses out of the cam and crank sensors but the voltages seem off.

Have a great day.

It would also be good to know how many miles on the engine, and if the ICM and coils have been replaced.

There is 104,000 miles on the engine. original coils and ICM.

I'm gonna speculate that the ICM is probably 26 years old.

ICM is best bet.

Thanks fellow Mechanics. I am a hack but I certainly enjoy diagnosing the problem and then replacing the parts. Thanks for the encouragement. I changed the ICM and ta Daaa . it runs smoootly.