Wire Fire / ID help (Page 1/1)
steve308 JUN 17, 08:14 PM
Had a blaze in the engine compartment in the harness that runs from the junction of wires near the alternator, and along the backside of the engine before it disappears into the drivers side bundle. I've tried finding a clear copy of the harness (86 2.8 auto) but I cant find one thats readable online. When I removed the burnt loom, only one wire had any damage and it appeared to me to look like it was chafed with only a small section of bare wire showing. I cut and spliced in a new piece of wire and let it run and drove it for a short run and all seems well, however, I don't want to have the car burn down. The wire color appears to be orange and black. Any guess as to what the wire does/control? Thanks.
Gall757 JUN 17, 10:20 PM
Most likely it is the fuel pump relay hot wire (orange with a black stripe).
hunter29 JUN 17, 10:41 PM
Get a FSM.. plenty on eBay
steve308 JUN 18, 09:57 AM

quote
Originally posted by Gall757:

Most likely it is the fuel pump relay hot wire (orange with a black stripe).



Thanks but of course more questions.... Would you suggest replacing the relay or so you think there is another issue that caused the wire to melt.

And thank you for the quick responce.

[This message has been edited by steve308 (edited 06-18-2022).]

steve308 JUN 18, 09:58 AM

quote
Originally posted by hunter29:

Get a FSM.. plenty on eBay



OK....what is a FSM....inquiring minds would like to know.

And thank you.
jdv JUN 18, 08:48 PM
Just a shot in the dark. Factory service manual
Gall757 JUN 18, 10:00 PM

quote
Originally posted by steve308:

Would you suggest replacing the relay or so you think there is another issue that caused the wire to melt.




Start with the fuse box. it is supposed to prevent melting wires, so something is not right with it. Look at the 30 Amp fuse called PWR ACC. Also look at the Fuel Pump fuse.

[This message has been edited by Gall757 (edited 06-18-2022).]

theogre JUN 18, 11:09 PM
Yes Check F-pump has 10a fuse...

But don't think whatever fuse will make circuits free of melting or worse. While Fuses etc blow for a direct/hard short to ground often won't blow for other problems.

Iffy FP Relay, OP switch or other things can cause burn up contacts or wires.
Example: See my Cave, Electric Motors

Or have exhaust too close or leaking melting wire(s) in the area.

Worse. Burned up wire on engine bay may have "burn" the rest of that wire thru the cabin. You need to pull the console check large connection below ECM and likely wire all the way to fuse.

Get FSM or Buy alldatadiy.com for a year. Has same data in GM "books" unlike crap Haynes and others.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

steve308 JUN 19, 10:33 PM
First and foremost thanks to all who offered advice and suggestions. Thought I'd update what I did and didn't find.

I seperated as best I could the wire that burnt from the rest in the loom. No other wires were burnt. The wire was repaired, heat shrunk and then covered with it's own loom. The rest of the wires were re-loomed and the entire run of wires was repositioned as best I could away from the block, headers etc.

The fuse block had no blown fuses. I changed out the 10 amp and the 30 amp fuse with new items just to be safe.

No damage near the ECM was found.

Spent a couple of hours removing the filter housing, intake tube and evap canister to access the relays. I want to thank the engineer who thought this was a good place to put the relays. I then spent another hour getting the relay off the bracket and unplugged. Swapped in a new relay. I checked every wire I could for damage and none was found. All new wire loom was installed and every thing was reassembled with the exception of the K&N filter that was cleaned and will dry overnight.

Loaded up a spare fire extinguisher and went for a drive. So far all the smoke is staying in the wires! I will drive it the next couple days and if it doesn't burn down I'll be heading to Carlisle on Thursday.

Thanks to you all again.

Steve