40 Dead after starter shorted... Where to start?

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Vae Victus

Vae Victus

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40 Dead after starter shorted...

My new acquired 1976 FJ40 stopped running after the starter appeared to short out. When that happened the wire leading from the harness to the solenoid caught on fire.

I have replaced the starter, replace the battery, and tested the wires leading to the battery and into the harness.

I have also checked the fuses and found nothing wrong. When I turn the key, absolutely nothing happens. What do I look for next?

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A bit more detail since no quick answers - I think the key remained stuck in the "starting" position due to rust/friction. I did not think to turn it back a 1/4 turn once it started (heck, I was just excited it cranked at all). After running for about 1-15 minutes in my driveway, and driving about a mile on our access road, it started making a very loud squeal/grind (which may have been the starter gear or the starter beginning to die internally after spinning for 15 minutes). And no, I did not hear the starter grinding like you often hear when a car is already stated.

The vehicle went slower and slower as I tried to get it back to the house. As I entered the uphill driveway, it completely died - went dark. No electrical signal anywhere in the car. I opened the hood and found the solenoid wire (the small black one, not the one from the battery) flaming. I blew it out and all was well.

That's how we got to this point.

Diagnosing - am I incorrect about what made the wire catch on fire? Is it plausible that the starter kept turning for that long and finally shorted out/seized up internally? The small starter gear was very worn, but I did not hear it grinding. The mating wheel in the engine was not worn. :hhmm::confused:
 
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check your fusible link. that protects the rest of your harness from frying. Your symptoms are consistant with a blown fusible link.
 
Fusible Link was not fried during the starter module short out. However, replacing the starter and reconnecting the disconnected FL did allow the truck to start again. Not sure anyone else has seen this but the starter seemed to be shorting out the entire truck without frying the harness (the battery was fried as well). It did fry the black lead from the harness though (the small gauge wire, not the big black battery cable from the Positive terminal). That is what caught fire.
 
Weird things can happen when ground wires are missing or otherwise "open". Without a starter/engine ground wire, the starter body can be "hot" when cranking and the easiest path back to the battery could be backwards through the solenoid and the solenoid control wire. That amount of current would burn up that wire.

I don't know if this is your problem, but it could explain why that wire burned up. I'd start by checking that ground wire.
 
sounds like starter solenoid contacts welded together. doesn't allow the starer to disengage. this effectively turns your starter into a generator. that little black smoking wire is certainly screwed, and i would check your ignition switch.
is the truck completely dead electrically?
probably burnt the insulation off the wire and it is shorting to the body or another wire.
 
edwjmcgrath said:
Weird things can happen when ground wires are missing or otherwise "open". Without a starter/engine ground wire, the starter body can be "hot" when cranking and the easiest path back to the battery could be backwards through the solenoid and the solenoid control wire. That amount of current would burn up that wire.

I don't know if this is your problem, but it could explain why that wire burned up. I'd start by checking that ground wire.
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Very good explanation. I'm a computer engineer and had EE classes in college, but that is the best explanation of an electrical principle I've seen.

I'll check the wiring diagram to see if I'm missing a ground wire that should be nearby.
 
cruisernerd said:
sounds like starter solenoid contacts welded together. doesn't allow the starer to disengage. this effectively turns your starter into a generator. that little black smoking wire is certainly screwed, and i would check your ignition switch.
is the truck completely dead electrically?
probably burnt the insulation off the wire and it is shorting to the body or another wire.
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Actually the little black wire did not melt thru, but the insulation did catch fire. I have not replaced it yet, but will. I recoated the bare section with liquid vinyl until I can troubleshoot things.

No truck is not dead - it is ok now that I replaced the starter and hooked the fusible link. It started and ran the other day.
 
If the wire didn't melt through but only the insulation melted, then I will change my theory.
My theory is that the starter kept running while the key was turned. This slowly discharged the battery by effectively shorting the battery + to - through the starter motor. Eventually, even the alternator stopped working without any field voltage, and everything in the car was dead. The insulation on the solenoid wire melted because the starter was so hot. The big, battery to starter wire insulation is a better material and it didn't melt. Now that you have a new starter, everything will be fine. But I would replace or lubricate the ignition key cylinder so that this doesn't happen again. But that's just my theory.
 
I always run two main engine grounds - one directly to a starter mounting bolt and the other to the alternator mounting frame bolt . Use at least a 10ga wire also to the fender with dielectric grease and internal tooth stainless washers .
Used to work at a semi truck shop , you'll learn quick about proper engine grounds .
Sarge
 
your starter shorted and seized that was the sound you heard. the wirings melted that created the circuit that killed your battery. i bet if you took the old starter apart everything is welded together. it may start and run but if you think liquid vinyl is a compentent repair you are crazy. i would be concerned about the length of the little black wire inside the harness, as it would have been hot enough to catch fire as well. and the wires it are surrounded by could have been damaged as well.
this is the type of thing that gives a vehicle electrical nightmares for ever. as far as checking grounds goes, i would check them. but if you have enough current draw to burn up wiring you have ground.
 
edwjmcgrath said:
If the wire didn't melt through but only the insulation melted, then I will change my theory.
My theory is that the starter kept running while the key was turned. This slowly discharged the battery by effectively shorting the battery + to - through the starter motor. Eventually, even the alternator stopped working without any field voltage, and everything in the car was dead. The insulation on the solenoid wire melted because the starter was so hot. The big, battery to starter wire insulation is a better material and it didn't melt. Now that you have a new starter, everything will be fine. But I would replace or lubricate the ignition key cylinder so that this doesn't happen again. But that's just my theory.
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Sounds like a good theory. PBlaster on the cylinder last week. Works better now - returns to run position after you release the key whereas before it just stuck in the "start mode".
 
i can guarantee that amp draw burned up that wire and not heat off the starter! good luck!
 
cruisernerd said:
i can guarantee that amp draw burned up that wire and not heat off the starter! good luck!
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So you think that when the starter finally fried after running for 15 minutes, it continued to draw amperage which turned into heat and began to melt the wire?
 
this is the wire to the starter solenoid correct? the solenoid is only meant to be energized momentarily, not for 15 minutes. having the circuit completed for that amount of time exceeds the limit of the circuits design.
maybe i miss read something, but i had something similar happen to me not to the same degree. my starter was rebuildable though. also if the starter stays engaged on the flywheel, as is spins faster to will start to generate current. you are probably lucky it wasn't worse.
 
If the solenoid wire insulation was burned along the entire length of the wire, then it likely was excessive current on the wire. If it's only near the starter end of the wire, I would suspect conductive overheating from the hot starter/solenoid.

The only way that the starter can stay engaged on the flywheel is if the bendix drive fails in the out position. This rarely happens suddenly. You usually have symptoms of a sticking bendix (starter noise and/or engine drag) long before it fails.
 
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