Thanks all for your input. With all the new parts in there the indication seemed to be that the wiring is the problem. I bought a used engine harness and am in the process of restoring it. Once good wiring is in we'll see it the problem is resolved. I will follow-up to keep everyone informed. I was surprised to find some dark oily substance on the connectors in the firewall connector at the fuse box. Is this normal, what is it and what's the best way to clean this stuff off? Thanks.
CK5
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1991 Chev V2500 5.7L ICM Keeps Blowing
- Thread starter GaBnn3
- Start date
Yes is normal. Iirc a mineral base solvent will work.
Truck-Lite 97944 NYK-77 Compound (2 Oz. Tube, Corrosion Preventive Compound For Electrical Contacts, Switches, And Junction Boxes) https://a.co/d/fir2tvo
Is the compound
Truck-Lite 97944 NYK-77 Compound (2 Oz. Tube, Corrosion Preventive Compound For Electrical Contacts, Switches, And Junction Boxes) https://a.co/d/fir2tvo
Is the compound
I have a 1991 V3500 Crew Cab, and since there is no aftermarket engine compartment wire harness for a 91 square body I built my own. I built it one wire at a time, and re-wired the whole engine compartment. My truck ran OK with the old wiring, but it runs real good with all the new wiring. The TBI, distributor, alternator, gauges, and all sensor inputs function perfect.
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Final update. Please excuse the delay. The new wiring harness is in and all the issues are gone. Cudos to American Classics in WA for the harness in pretty good shape. There is a learning curve however. I was intend on getting the correct harness. So I had to go to the opposite side of the country for that, which I did. However I then learned that the 4L60E connector can be re-wired for the 4L80E. There were many more harnesses available for the 4L60. Many were in excellent shape compared to the one I got. If I had to do it again, I would go that route. I wanted originality so I restored the harness with the tubing. I was intimidated and slow to get started but it wasn't as bad as I feared. I didn't replace all of the tubing but should have, because it is easy enough. The issues that I had may or may not be typical for trucks this old, but due to age and use a problem harness is not a surprise. I have seen some Youtube videos of square bodies with mystery problems that I suspect may have a similar cause. If I can do it you can too. So don't be intimidated. Thanks again to all those with input on this and the related issues I ran into along the way.
good news. Have you inspected the old harness to see if you could find the short responsible for blowing fuse ?
No I did not. It never occurred to me. When everything worked and the check engine light out that thing was old news. It probably would have been a learning experience to do that. But it would have been a project in itself and I have too many right now.
