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My son is having electrical problems with his 78 and when I went to look at it last night I noticed the coil was VERY hot. It wouldnt burn you but it was too hot to keep your hand on for more than a second or two. What causes a coil to heat up like that?

Also, he and a friend (I warned him against screwing with wires without me watching ) tried to fix it while I was working and may have made things worse. Right now the truck won't run by itself but if you give it a squirt of starting fluid it starts right up. I checked the power at the fuel pump (NAPA electric, about 6 months old) and it was fine, but when I pulled the fule line off and had him crank the engine there was no flow. I think it is because of a short in the electric somewhere not because of a bad pump, but who knows...

A final question, on the inner fender hump on the passenger side there is a little metal box/guard thing with some electrical stuff (relays?) in it. What is in that protected area and would that be the problem?

Thanks in advance for any help. You guys have helped my son (and me) a ton in the past!

under that cover is the fuel pump relay and one other relay which slips my mind right now. if you are getting power to your pump, but when my truck wasn't getting fuel, i changed the relay and it fired right up...

The other relay under that metal cover is the coil resistor bypass relay. It also works with the pump relay to supply power to the fuel pump when cranking. Here is a breakdown on the fuel pump power, because it can be confusing to test:

Key to Start: relay supplies pump with power
Key to ON, motor spinning: pump gets power
Key ON, motor not running: no power to pump
Alternator/charging problems or trouble with the relay can screw this scheme up.

The bypass resistor supplies the coil with a full 12 volts when cranking the motor over. Once it is running the resistor (right on top of the coil) is in line ahead of the coil and steps the voltage down. With your coil getting hot, I'd suspect that somehow the resistor bypass relay or a wiring problem is sending 12V straight to the coil all the time. If you have a voltmeter, check the voltage between the +side of the coil and the -post of the battery. It should be under 10 with the motor running, around 12V when the starter is cranking, and pretty much nothing the rest of the time.

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

The resister gets very hot on both of my trucks too. With the key on , with or without the eng. running.

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OK, I'm over it. Where's the beer?

All this sounds like it may have to do with my problem. I have to pump the gas pedal to keep mine running.

OK, after messing with this thing off and on for almost a month now....

We replaced the voltage regulator on the driver's side fenderwell and a bunch of wires were melted together right where they reach the regulator (either caused by another problem or the start of this one).

We still have electrical issues. There is limited power when the key is in ACC or OFF position, but when it is turned to ON or START it all goes dead. We read online where a bad keyswitch could cause this so we ordered one and put it in today, no change in function (read $40 wasted...).

A wierd twist is that when you pull out the headlight switch (with key in ACC or OFF) you get power to the cab (heater fan works, radio, etc..) but the headlights don't. Turn off the headlights and the cab power is lost. (and no the headlights don't come on either).

HELP!

sounds like you melted your main wiring harness. this happened in my dad's blazer. somewhere in the bunch of wires they all melt together. i'd try uncovering all your wires. cut the factory tape off of them. and see if you can find the spot and fix it. hope this helped. good luck!

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1980 luv 1.8 finally running!!!...... and then like a moron i sold it
got another one!!! 1980 mikado. v8 swap here we come... nope divorce and cross country move happened.
got another one!!! 1980 4x4 mikado sport. rusty beater for now...

Check your grounds, pull them off of the block and body and clean up the area and reinstall (the main ground from the battery). Grounds will do funny things when they are not makeing a good connection.

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Certified pilots, looking down on people since 1903.

check your battery cables. if they're the kind that clamp on to the wire. i had a set one time that the guy before me painted the whole thing including the surface that touched the wire. when i tried to start my car the doors would lock.

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1980 luv 1.8 finally running!!!...... and then like a moron i sold it
got another one!!! 1980 mikado. v8 swap here we come... nope divorce and cross country move happened.
got another one!!! 1980 4x4 mikado sport. rusty beater for now...

My son and I spent all day Saturday opening up the entire wiring harness, isolating circuits, and looking for the short causing the weird stuff that had been happening (including not running...).

Anyway, I finally went in the house and printed this thread out again and said to him that it has to be something simple let's check all the grounds again. At that point I noticed when he and his friend put on the new battery cables they never grounded the battery to the frame, only to the engine. Well, 30 seconds later she was running like a top again.

So, to beat a dead horse....make sure you have a good ground to the engine and one to the body/frame.

Thanks to everyone who helped out!