ICM? PCM?
#1
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
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
#2
Senior Member
How long did it run before acting up? What year is the car? What did the 3.8 come out of?
#3
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.
#4
Retired
I believe your car has the OBD2 connector, but an OBD1 system. 99% of today'* 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.
If it starts and runs good until it warms up, then develops these conditions, then I would start looking at the ICM.
__________________
Retired Administrator
Retired Administrator
#5
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.
Have a great day.
#6
Senior Member
True Car Nut
It would also be good to know how many miles on the engine, and if the ICM and coils have been replaced.
#7
#8
Retired
I'm gonna speculate that the ICM is probably 26 years old.
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Retired Administrator
Retired Administrator
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NeedforFieros (05-17-2020)
#9
Senior Member
ICM is best bet.
#10
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.
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carfixer007 (05-18-2020)