1991 pont 3.1 ecm fuse blows

[zao420]

Hi everyone this is my first post on here have been browsing for a few months.

anyways i have a 1991 sunbird with a 3.1. they other day it died on me well driving it. after checking around the ecm fuse was blowen. i put a new fuse in it and when i turn it to the on on position it blows again.

i have disconnected my fuel pump and injectors and it still blows the fuse. has anyone here ever had something like this happen or know a good place to start looking for the problem.

Thanks

[DEI37]

That's weird. I'd probably say that either there is a wiring issue, or the ECM shorted itself, and is junk.

[Guest]

That's weird. I'd probably say that either there is a wiring issue, or the ECM shorted itself, and is junk.

yep, next I would try is unplug the ECM and turn the ignition on with a good fuse if it doesn't blow, you probably have a bad ECM (only probably, because there could be something wrong with a wire in the harness still on an output from the ECM)

If it still blows, start checking the harness itself, there might be some melted wires.

Also I believe the canister purge runs off that same fuse, try unplugging it as well.

[zao420]

Over the weekend i was working on it. and if i unplug the ignition module it doesn't blow the fuse. so i am thinking it is that.

i have unpluged the computer and it still blew the fuser.

so with that info do you guys think it is just the ignition module or could it be somthing more?

[IsaacHayes]

Makes sense to me the ignitino module is faulty then. Try getting one cheap from a junkyard first to see if that fixes it before dropping ~$90 for a new one. I think i have a couple sitting in my garage that were good that I took off after getting new ones, then later I found out my problem was something else.

But it does sound like yes the ICM is bad, did you try removing the coil packs too? Perhaps one of those is bad, and those sit on top of the ICM...

[zao420]

i haven't removed the coils yet to check, only really have time to do it on the weekend.

one question is the ignition module the same on the 91 cavi and the 91 sunbird?

[Syn]

check your grounds

[tractorman]

to avoid buying more fuses... you can wire in a test light to each side of the fuse connector. When you turn the key on, it'll light up. Start unplugging things... when you unplug the guilty component, the light will go out. Then you can do the same test with a fuse and make sure. The ignition module seems pretty likely to me though. I'd also try removing coils just in case... but they don't seem likely.

[zao420]

so went to pick a part on the week end and got a ignition module with all the coil packs on it and put it in my car every thing seams to be working ok now.

is there anyway to test the old coils besides putting them in the car?

[zao420]

so i have my car running alright now, but my idel jumps all over, and i get code 35 IAC, des anyone think my computer got messed up when the ignition moduel shorted out.

I am going to run an idle relearn and see if that fix's it

[Juglenaut]

The outputs or drivers of the ECM are diode protected chances are it can be repaired.
Atleast load protected. Sometimes it takes back probing alot of wire to find the problem.

You may have to flash the memcal. Try relearn first.

[NeonKnight]

IAC is your Idle Air Controller, it sits on top of the throttle body. it is most likely dirty and old, you can pull it out and try to clean it... but you have to be sure not to press on the pintle or anything. it is geared inside or something, and you can not push or pull it. try getting a new one, or get one from a junkyard.

I took the IAC out of my lumina and cleaned all the carbon build up off it with degreaser... lol... and my car idled like shit, sounded like a V8 with the flowmasters. it was HOT! lol i loved the sound... hated the weird idle, and when i would drive down the street once you gave it enough gas it would stay at like 1500 rpms and not die down till the car was almost completely stopped.

was fun times