what do you think

[Cj Ford]

how cold does it have to get before a 7.3 wont start with out the glow plugs working???


the reason I was wondering I have noticed my truck is cranking longer when I start it after it sits over night.. the glow plug light is working and it starts up good doesn't run rough once it starts.. just seems to crank over quite a few times more. the controller was replaced last winter as it quit and the truck would not start at all but I cant remember how cold it was then..

So this morning I fired it up and shut it down right away so it didn't build much heat in the motor.. Then restarted it, I cycled the glow plugs the motor made a few revolutions and fired right up really fast... think it may be the cold oil taking longer to get pumped up and firing the injectors ..???

this morning it was 18F when I tried this

[cchase]

I would think you are on to something with the cold oil

[FordCowboy]

Could be cold oil, old batteries or other stuff. I would think if your glow plugs weren't working at all it wouldn't have to be very cold for the truck to not fire. I've had a few times when mine weren't working due to a bad relay and it wasn't that cold out and it wouldn't fire. If you really want to know unhook your relay and see if it starts.

[Cj Ford]

the batteries are new last year and the starter is a few months old.. it spins over very fast ... just doesnt fire up as fast as it use to ...

so basically what I wanted to know is if it was 18 or 19F would it start at all with out the glow plugs working.. I didnt think it would but wasnt sure..

[shu873]

I'm confused Chris, did you say you have replaced the GPR? You said "controller" but wasn't sure if that's what you meant. You can check your GPR with a simple test light, you can also test each individual glow plug with a test light by simply unplugging the harness and touching the two outside wires on each side of it (but be careful not to touch the inner wires).

To answer your other question, it may start in 18* weather w/o the glow plugs all working, but it also may very well not. At the least it would have to be cranked a long time to build enough heat. I just got done checking a friends early '99 for him and wound up replacing the GPR.

[bottledgt]

it would be hard to start in 18 degrees without GP...for sure

[Cj Ford]

ahh well I guess Ill open the hood and have a look ...


I just didn't feel like working on it but I suppose I should check it cause it will be getting colder here winter has just begun, and I dont plug it in unless its really really cold out...

ya glow plug controller relay what ever ya wanna call it .. last year I had to change it so I went to the dealer to get one I called it a glow plug relay the ford parts guy said its listed as a glow plug controller ..

I said same sh*t different pile I need one

[bottledgt]

oh and im just talking about diesels in general...i havent personally tried a p stroke that cold with no plugs

[scheidt27]

I just changed over to the Stancor relay today. My truck was doing the same stuff yours was. It would crank fine but took alot to get it going. Switched over to the Stancor relay today and it fired right up after sitting for 3 days in cold temps(0-20 degrees). One of the best 50 bucks ive ever spent on the truck. You wouldnt believe how much beefier the Stancor is compared to the POS stock one.

[NCHornet]

Glad to see another using the awesome Stancor relay!!!

Back to the OP, there is such a thing as a GP controller, the CA trucks use one instead of a relay, and it is $$$$

The proper way to test GP's isn't with a test light, it is with a ohm meter. If you don't have a multi meter get one for $20, they come in real handy!! Here is the proper way to test the GP system. Any ? PM me

Troubleshooting GPR & GP's

NCH