Smokin wires

[mr_smith]

I know it's a common problem for the two gp relay wires to get too hot. The truck I'm working on (91 f250) is now doing this but it's doing it all the time. I got it fired up without using the gp's and while running the harness is still smoking..

I was under the impression those wires only get hot when cycling the gp's..

Also this appears to be an aftermarket connector..

A lot of the wiring in this truck is cobbled together.. There's even some romex under there haha

Are those wires always hot when the key is on?

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[tradergem]

Yes, those wires are hot when key is on. You sound as if they are shorting out with other wires in the connector.

 

[mr_smith]

Yes, those wires are hot when key is on. You sound as if they are shorting out with other wires in the connector.

So those wires stay hot when the truck is running? Why do you think other wires are shorting with them in the harness?

 

[tradergem]

Sorry I spoke before I thought. The glow plug wires connect to the B+ hot side of the starter relay so they are hot all the time even when key is off.
The other end of the glow plug wires are connected to the glow plug relay and normally nothing happens until you start the truck and the glow plug controller turns on the glow plug relay which sends power to the glow plugs for about 15 seconds or so and maybe another on off cycling for 30 seconds or so depending on engine temperature.

If your glow plug wires are staying on for more than 30 seconds and are smoking, the it could mean the glow plug relay is sticking in the on position or the glow plug controller is keeping it in the on position causing the wires to over heat and could even cause the glow plugs to over heat.

I would trouble shoot the glow plug relay and the glow plug controller first and replace if needed. The connector should be cleaned and inspected anyway. After the part of my connector broke where the glow plug wires passed through it I butt spliced my glow plug wires outside the connector with both solder and crimp connectors covered with heat shrink tubing and I added another pair of 10 gauge wires in parallel to the original glow plug wires from the starter relay to the glow plug relay to provide more current path and reduce heating of the wires.

 

[typ4]

Take the big glow plug wires out of that plug and solidly connect them together, that is a factory plug and it will eventually melt at the GP wires
Do yourself a favor and take out all the added on wiring hacks and get it as close to factory, or reliable with good connections . It will make you happier in the long run.

 

[mr_smith]

Sorry I spoke before I thought. The glow plug wires connect to the B+ hot side of the starter relay so they are hot all the time even when key is off.
The other end of the glow plug wires are connected to the glow plug relay and normally nothing happens until you start the truck and the glow plug controller turns on the glow plug relay which sends power to the glow plugs for about 15 seconds or so and maybe another on off cycling for 30 seconds or so depending on engine temperature.

If your glow plug wires are staying on for more than 30 seconds and are smoking, the it could mean the glow plug relay is sticking in the on position or the glow plug controller is keeping it in the on position causing the wires to over heat and could even cause the glow plugs to over heat.

I would trouble shoot the glow plug relay and the glow plug controller first and replace if needed. The connector should be cleaned and inspected anyway. After the part of my connector broke where the glow plug wires passed through it I butt spliced my glow plug wires outside the connector with both solder and crimp connectors covered with heat shrink tubing and I added another pair of 10 gauge wires in parallel to the original glow plug wires from the starter relay to the glow plug relay to provide more current path and reduce heating of the wires.

Thanks for taking the time to write all that. How does the glow plug controller know when to stop drawing all that power? I don't think I let it run for more than 30 seconds because we noticed the connector was starting to smoke lightly.

What I want to do is run heavy wire from the relay to the solenoid with an online fuse and skip the connector altogether.

I want to make sure there's nothing else that could be wrong before I do that though..

 

[mr_smith]

Take the big glow plug wires out of that plug and solidly connect them together, that is a factory plug and it will eventually melt at the GP wires
Do yourself a favor and take out all the added on wiring hacks and get it as close to factory, or reliable with good connections . It will make you happier in the long run.

I probably won't keep this truck too long, I got it super cheap because the guy needed money and it didn't start. It just needed batteries. I really need an extended cab or 4 door.

I have bad luck with wiring and I don't think I can decipher what's going on under there lol

I don't think it's the factory plug, it's shiny black and all my other idis are gray. Also there's about 8 inches of electrical tape you can't see from when it was redone. I could be wrong though.

Are you the guy that sells cap and I ring kits? If so let me know how I go about ordering..

Thanks for the help

 

[Joseph Davis]

check to see if the throttle cable wore though the wires on the glow-plug solenoid?

 

[mr_smith]

check to see if the throttle cable wore though the wires on the glow-plug solenoid?

Wires all look fine

 

[tradergem]

I'll try to get some pics of my truck tomorrow and post them. If you know how to use a 12 volt test light or a multimeter it is not hard to test the glow plug controller or relay. Check in the Tech Article section for more useful info.

 

[mr_smith]

I'll try to get some pics of my truck tomorrow and post them. If you know how to use a 12 volt test light or a multimeter it is not hard to test the glow plug controller or relay. Check in the Tech Article section for more useful info.

I have both.. I'll poke around and find out how to do it. Thanks again

 

[mr_smith]

So I just started the truck and let her run, wires smoking and all.. After 30ish seconds the smoking stopped..

I think I may have gotten ahead of myself and this is just the classic 2 gp wires smoking..

I want to run a new heavy wire with a fuse so the next guy doesn't have this issue.. What do y'all recommend?

 

[Joseph Davis]

here is what I used on my 1990 F-250 and it help me make since of what the hacker did to the truck I drive now. the yellow wires connect to the Solenoid there is 2 wires with fusible links in them, the yellow wires break down over time and need to be replaced if they shorted out. I replaced all the wiring that looked suspect in mine and she runs and starts Great now. I hope this helps. Good Luck.

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[icanfixall]

Sadly this plug is not capable of safely passing enough current to fire the glow plug relay.Thats why the engineers decided to use two wires instead of just one. Then if you open the harness plug you can see how small the male and female side of the plug really is. I did what you want to do. I replaced the two yellow wires with one heavy wire.Ran it directly from the fender mounted solenoid to the controller. I went to an auto radio install shop and purchased the heavy cable and lugs from them. Its multi strand speaker wire designed to carry heavy amp and speaker loads. Its very flexible too. It was 6 or 8 gauge. Sad that I can't recall what size it was. You really do not have to remove all the old original wires from the harness either. Just cut the ends back so the new single wire fits. Remember it will be a dead wire in the harness bundle. Also please disconnect the hot battery leads when working in this parts. Our trucks have several items that are ALWAYS hot with power. the starter, the alternator and the glow plug relay is always hot. If when working on these items you accidentally ground the wires feeding power to them you instantly smoke those wires because a direct ground feeds all the nearly 2000 amps thru the tiny wire to ground... smoke and melting happens..

 

[typ4]

Yes I am that guy and all of my trucks and harness parts for that connector are black. .
If yuou just cut those 2 wires off each end of the connector and yellow butt connector them with a heatshrink butt connector you wont need to worry about the addition of a wire.
The wires will carry the current, the plug pins wont.