Weird glowplug issues...

[aofarrell2]

So I should start by saying I just got this truck recently, and I don't know much about it other than the original owner took good care of it (maintenance records) but the person who owned it before me was a complete idiot.

That being said...

I am having the most frustrating issue with the glowplug system and it makes no sense to me... I can tell the glowplug controller was replaced recently, all new glowplugs, new glowplug relay, and yet it just does the afterglow when I turn the key on (although not consistently). All glowplugs read 0.4-0.5 ohms. All glowplugs are getting nominal system voltage (12-12.5) if I manually activate the relay. Batteries are good. All the wiring is hooked up correctly and the controller has a good ground.

Even if I manually activate the glowplug relay the glowplugs apparently still won't glow, even after a minute and a half the truck still makes no hint of firing. Plugging in the block heater, or heating the intake with a propane torch will start it just fine, so it's not a fuel issue.

Am I wrong in concluding that the glowplugs are to blame? I'm just find it hard to believe that 8 brand new plugs wouldn't be glowing with 12v applied, even if they aren't Berus they should still glow, ya know.. I have no clue what brand they are as the P/O installed them. It's getting new GPs shortly anyways as I'd be surprised if they are Beru's. All but one of the connectors are OEM and they all make good contact so I'm at a bit of a loss as nothing appears to be WRONG.

I never had this much trouble with my '90 IDI even with a couple of bad GPs.

Insight is appreciated!

 

[Randy Bush]

In your testing did you check that you are getting power to the glowplugs with a test light? Could be such a thing as no power there for some reason.

 

[aofarrell2]

Yes I checked, every glowplug has 12v with the relay on.

 

[The_Josh_Bear]

Could be an amperage problem. Check the grey plug by the the passenger fender by the A/C housing. It's a 10 or 12 wire plug and the two large gauge yellow wires are the supply to the GP's. This plug often burns up and you get 12v but no amperage.

 

[franklin2]

Ina discussion the other day, most people said they got .2 ohms on a glowplug. I would pull a glpwplug and see what you have. If they are not beru's, you know you are flirting with disaster don't you? I think I would keep pluggng it in and not use the glowplugs till I changed them out.

 

[DrCharles]

Could be an amperage problem. Check the grey plug by the the passenger fender by the A/C housing. It's a 10 or 12 wire plug and the two large gauge yellow wires are the supply to the GP's. This plug often burns up and you get 12v but no amperage.

I believe OP said there was voltage directly at the glow plug. Therefore there is amperage and the feed connector cannot be burned up.... UNLESS the GPs are open-circuit, which they're not since there is tenths-of-ohms at each one while disconnected (right, OP?)

 

[aofarrell2]

Could be an amperage problem. Check the grey plug by the the passenger fender by the A/C housing. It's a 10 or 12 wire plug and the two large gauge yellow wires are the supply to the GP's. This plug often burns up and you get 12v but no amperage.

I don't seem to have that 10 or 12 wire plug. The glowplug feed comes directly off of the starter relay, and that connection and wiring seems to be in good shape.

I believe OP said there was voltage directly at the glow plug. Therefore there is amperage and the feed connector cannot be burned up.... UNLESS the GPs are open-circuit, which they're not since there is tenths-of-ohms at each one while disconnected (right, OP?)

All of the GPs are at 0.4-0.5 ohms so no open circuit, and yes there is 12v at each plug.

I'm going to pull one of the plugs next time I can get it in the shop (backhoe in the shop right now so no room...) and see just what they are.