1989 s10 ECM 1 keeps blowing

[Chevyman1987]

Ok so I got a 1989 s10 with the 4.3 ok my ECM 1 keeps blowing I can put a new one in and crack it up and a min later it will blow. It did the same thing last year and I put a 30 amp fuse in and now it's doing it again but like I said it won't run long what can be the problem

 

[Chevyman1987]

Ok so I just went out and cranked it up and set there and ran for 5 mins fine I went out the other day and cranked it up let it run for a min put in gear started to back up and blew this time it did great

 

[Chevyman1987]

Any help would be great

 

[RetroC10Sport]

I have all the wiring diagrams to that, let me poke through them and see what all is on that circuit and get back to you.

 

[Chevyman1987]

That would be great thanks

 

[RetroC10Sport]

Oh damn, my sincerest apologies, my mother in law was here for a week and a half and I lost my mind. I will look at those tonight.

 

[RetroC10Sport]

Okay, the ECM I (ECM/Ignition) fuse goes to:

pink/black wires

The Vehicle Speed Sensor
TBI Injectors
ECM
Electronic Spark Control
Electronic Vacuum Control valve

The first thing I would check is the TBI wiring, it's not uncommon for them to get pinched between the TBI and air cleaner.

Then the VSS wiring all the way back to the tailshaft, that gets pinched sometimes as well.

I've had experience with the above problems so that's what I am suggesting to look for first.

NEVER put in a higher amp fuse than what is called for. This can and sometimes will result in a fire.

Will it blow if the truck is just turned to run for a few minutes or does it have to be running at the time? You can generally narrow it down quicker that way.

 

[Chevyman1987]

Sometimes when you turn the key on it blows and sometime it does it while it's running. I will check all that stuff out. Do you know what size fuse that should be used. Thank you for your help

 

[RetroC10Sport]

10 amp.

 

[Georgeb]

I would start looking for a short or worn through wires. I had a 96 silverado that kept blowing the fuse that had the MAF on it. Found it one day while poking around the harness behind/below the distributer. I noticed some of the magic smoke got out of the wires. It had a chaffed wire shorting to ground and it melted the one next to it.

 

[Chevyman1987]

I just found mine it's shorting out behind the distributor. So now just gotta find out how to pull the wires up where I can tape them thank ya for all the help. And thank you retroc10sport after I read your post I went out started it up wiggle the wires and it sparked