LUVTruck.com

Hey everyone,

My glow plug light comes on intermittently when certain electronics are engaged (turn signals, hazards, radio), and stays on when the headlights are on. This also causes the engine temp to rise considerably (that's what glow plugs do, correct?)

This is the first diesel I've owned (82 LUV), and I'm a mechanical novice, but any suggestions are appreciated. Thanks.

Well, they wouldn't raise up the whole temperature of the motor, glow plugs only really heat up the air and diesel going into the cylinder. I also have no clue why that light is on with other access., i'm thinking there's a short or your computer is screwed up, if you do fix it however you'll have to get new glow plugs, and if you can't get it out use some liquid wrench, if you still can't you'll have to pull the head .

We had a bad relay to my glow plugs that caused them to swell so they stuck in the head, using some of that LW helped get them out, and we had to eventually replace all of them, cranks up nice now.

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-Old ride-82 Luv diesel 5spd with some upgrades
-Past rides-82 Sierra, 78 Coupe De'Ville, 91 2dr Blazer, 86 RX7, 86 Porsche 944T (rear-ended and totaled)
-Curr. rides- 1970 Ford LTD 4dr, 390 4Bbl, 2nd owner! With a few Extras 00' Civic beater...

It sounds like a short to me. If you have a test light or a meter, you can check it easilly: (I don't know how technically adept you are, so I'll try and make this as descriptive as possible. I appologize if it sounds condescending.)

Ground the "common" side of the meter , or the "roach clip" side of the lamp, to some common piece of metal on the truck, like the frame or the engine block. If you're using a meter, set the Voltage switch to measure 12V or more. (Don't select Ohms or Amps, or you'll blow a fuse in the meter or maybe even kill it.)

With the key (And all accessories INCLUDING the dome light) OFF, touch the light/meter to the power rail connected to all the glow plugs (This is on the passenger's side of the head, near the injector pump. It's a strip of metal that connects each of the plugs via a copper/brass stud and a nut.). The meter should register 0V, or the test lamp should be off.

Turn on your headlights. Keep the key off.

Touch the probe to the power rail again. If the light/meter shows a voltage to the plugs, you have a short, probably somewhere between the fusebox and the glowplug circuitry. All this is under the hood and fairly accessible, and should make tracking it down easier.

If there is no power to the glow plugs, you probably have a short between the fusebox and the indicator lights, via the light switch . Good luck under the dash. The good news is that, in this case, you probably didn't fry the glow plugs.

As far as heating goes, I wouldn't think the plugs would really do that much. A short could create a condition where the charging system is trying to overcome the battery drain caused by the short, causing the alternator to load down the engine. But that'd have to be a serious short to cause engine heating. 750W=~1HP, so you'd have to be drawing about 62 Amps at 12V for even this much additional drag. I'd expect that to blow a fuse.

Another possibility is that the short is causing the ignition circuit (A solenoid used to cut off the fuel supply) to malfunction, somehow causing a fuel-rich condition and heat. That's just a guess. You could check it by seeing if turning on the headlights with the engine running causes a black cloud of exhaust.

Good luck with this.

Sounds like you lost a ground somewhere, either between the body or for the dash. My guess is the motor isn't heating up, but is reading incorrect due to an electrical problem.

Check for a ground wire under the hood, likely between the battery and the body, or the motor/chassis and body. If you find it, be sure both ends are not only connected, but clean and tight.

When I first wired up my motor, my gauges were reading wrong due to a ground wire I missed for the dash. When I finally found it, and reapired it, the gauges were back to where they should have been.


Just a thought.

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Bona Fide diesel fanatic.
1994 Chev S10 Ext Cab Isuzu Diesel 5spd
Kubota B6100 HST diesel