Mechanics

90 BLOWS ECM FUSE AND MORE

1990 Pontiac Sunbird

Electrical problem
1990 Pontiac Sunbird 4 cyl Front Wheel Drive Automatic 83500 miles

while driving car shuts off, replace the ECM fuse and it starts and drives until it blows the fuse again - no rhyme or reason to what makes it blow
Have looked for grounded wires, pulled on wires, tapped relays, banged on the ECM - can't " make it happen"
additional info - infrequently you go to start it and you get nothing - wait awhile and it will start -
NOT HOT STARTER will jumper
also car was overheated before ECM problem but No Start problem is older
Thoughts? Help? Direction?
Avatar
Jnsbill
June 29, 2010.



Hi, thanks for the donation, usually when you donate one of the moderators will jump in. I'm not a moderator. Your fuel injector is on that same fuse circuit. I can't say the injector is faulty. It may not act up till it gets hot. You can do an ohms test on the injector, but, may not be conclusive? 1.6 to 2.0 ohms depending on litre size of engine. If it is way out of specs, replace the injector. There may be another issue, IF the ecm supplies ref voltage off that same fuse, any sensor or wiring circuit that uses ref voltage could be causing a problem? Any applicable trouble codes?

Tiny
Internetmechanic
Jun 30, 2010.