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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: CreativeNotice on February 27, 2010, 07:30:04 pm
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Chevy c20 1985, 350.
Ok, so I pulled a super stupid today.
I disconnected the red wire from the back of my alternator and let it fall to the side, it made contact with the body of the alternator. I got sparks of course but I also got some smoke from wiring up on the firewall on the driver's side. Smoke appeared to come up to the left of the brake cylinder.
I disconnected the positive bat cable and finished working on the valve covers... I then reconnected everything and attempted to start the engine. I got a split second of power to the starter and then nothing, no power at all.
So I need to trouble shoot this and electrical is far from my strong suit. Can you guys give me some direction on where to start. I looked at the wiring diagram and got lost. http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/81-87_V8_engine.jpg
Thanks in advance.
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Trace each wire from end to end and look for damage; melting, spark burns, etc. Also look for burnt fusible links.
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Did something similar with mine. It was a fusible link on the firewall next to the brake booster. Grab some wires around there and feel them. You know how to check for a bad fusible link?
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I do not. Do explain further pls.
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Think like when you grab a wire. It'll be hard because of the metal inside the insulation. If your fusible link burnt up, the metal is gone. It'll be spongy and more flexible than normal. You can tell where it burned up; cut that out and put in a new segment of fusible link at O'reillys or the like.
This is a terrible explanation, and the more experienced guys will chime in soon :D
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http://forum.73-87chevytrucks.com/smforum/index.php?topic=11972.0
You may have fusible links at your starter B+ terminal, Alternator, and at the bulkhead connecotr. Check them all.
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Where is the bulk head connector? Is that the large block on the firewall below and right of the brake cylinder?
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I'm sorry, I think I inhaled too many fumes today. I meant junction block on the firewall. It looks like this
Yes the bulkhead connector is the sqaure connection but that's not the one you want.
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Taking what Layne and Vile has said... I'm thinking this wire might be the culprit. it's the the area I saw the smoke and it's spongy.
What's the black connector called, I"ll need to replace that as well. I bet. It looks solid, not something that's designed to come back apart.
(http://lh4.ggpht.com/_W-gt6YUjbZI/S4nqgHzyb_I/AAAAAAAAAEY/xNMIaRTnNaU/s800/HPIM0220.JPG)
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The black part is just the connector where the wires go together. Is the whole wire burnt or just one spot. You may be able to cut the bad spot out, put a new ring terminal on it, and put it back on. If not, you just need a new section of fusable link, and a yellow but splice to tie it all back together. Use some heats shrink tubing to seal up the butt splice to help seal it up
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I wouldn't recommend shortening a burnt fusible link. Just replace it. Cut the black piece off and make a new one the same length and gauge. Solder the connections with a splice clip and heat shrink it.
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Got the beast running again. Thanks.
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c'mon...details....what did you end up doing..this is a learning website and we are all interested.
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Lol ok, so it was a fuse... just a regular 'ol 15a fuse. So in the spirit of learning, I offer up my ego as a testimony to others to check the darn fuse block before hunting around for bad wires.
On the plus side during my hunt I did find tons of poor wiring (old splices no longer used but not removed, horriffic solder jobs etc.) from previous owners. This truck must have had 10 different accessories wired in over the years.