Burning wires

KCoppola

New Member
Apr 5, 2005
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atlanta
There is a wire that keeps burning up in my car driving me nuts! it is a wire that is a single wire from the solenoid, then about 6 inches later, there is a fusable link, then it separates into 2 wires. the wire keeps burning up before the link. recently it burned up and arc out onto the solenoid bolts, causing my alternator to fry. this prompted me to buy a 20 amp alternator. i got it hooked up, and about 15 seconds later, the wire burned up again, in the same place. i am pretty sure i got her shut down before i did anymore alternator damage. what could be the cause of this, and what is a possible fix?
 
There are no Black wires with a red stripe listed in the Mustang wiring diagrams for 88-90 model cars
.
Black with Orange stripe - Alternator.
Black with Orange stripe - EFI Computer, Ignition, fuel pump. See the attached diagram.

Things added on to your car are very suspect like stereo, electric fan, alarm system, etc.
They may have been added to this circuit since it was handy.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Diagram courtesy of Tmoss & Stang&2birds
fuel-alt-links-ign-ac.gif


http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
 

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That sounds to me like the fuseable link on the power wire to the alternator (blk/orange,blk/red or whatever shade of red your eye sees). You should check your grounds to make sure all is good. After that, I would put a larger fuseable link in there. Or do what you should do and upgrade the whole wire to a 4 gauge power wire and a fuse in preparation for a 3G upgrade. (~100A fuse for stock alt and 175A for 3G) You'll be upgrading in the future anyways, trust me.
 
302RollinHard said:
After that, I would put a larger fuseable link in there.
Bad advice - the fuseable link, like a fuse serves to protect the wiring. It is supposed to burn out or blow before the wire burns up & starts a nasty electrical fire.
 
the alternator is fine, i had it tested. it is "black with orange" i guess.....the car is 18 years old... i suppose i need thicker wire, since the alternator that i just got is a 200 amp?
 
The fuse link problem you are having may not be related to your alternator. Fix that problem first and then fix the too small wiring on the alternator.


See the diagram I posted earlier. Start disconnecting things that are supplied power by the black orange wire. Start with the things that are most distant from the fuse link like the items on the red wire. Power up the circuit and see if it blows. When you disconnect the failing component, the fuse link with quit blowing or burning. You may want to use an inline fuse holder and 15 amp blade fuse in place of the fuse link.

You definitely need a bigger wire with a larger alt. See WWW.partsexpress.com for the fuse & fuse holder.
Fuse @ $3.90 each (need one) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=071-952

Fuseholder @ $5.80 each (need one) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=263-630

A 200 amp alt will need 2 gauge cable & a 2 gauge ground.

The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges. Any car that has a 3G 130 amp alternator needs a 4 gauge or larger ground wire running from the block to the chassis ground where the battery pigtail ground connects.
 
i am not smart enough to figure out that diagram guys....i have basic wiring skills at best. as far as i can tell, that fusable link is hooked up to ONLY that hot alternator lead, and doesn't have anything else running off of it. i am gonna ****** it out and just run a new 2ga. hot lead, and a 2ga ground for the main circuit. the harness that i did not have to cut isn't the one giving me problems ( i think). the car already had a 130 amp alternator on it, now it is getting a 200 amp piece.
 
I'm not following this, so take it for what it's worth. The stock charge cable has the sense wire on it, so the sense wire would need to be removed (and reconnected to the solenoid) if you want to remove the stock charge cable, or you'd have to keep the stock charge cable connected at the solenoid (but capped off/insulated at the alternator).

One alternative if you're feeling hinky about this is to use the harness from FFI that Kevin (04 Sleeper) used. I believe it loops the sense wire back to the alternator positive stud and allows one to remove the stock charge cable (or disco' it at both ends). I had always though that one wanted the sense wire away from the alternator so it could more accurately see a voltage delta (due to voltage drop, etc) but with quality cables, it doesnt seem to matter. JRichker can comment on the technical aspect of that if you have questions.

Good luck.