Napa Glow plug relay

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Nov 17, 2011 | 03:15 PM

ajfetterman

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Napa Glow plug relay

Im having trouble starting in the colder temps. I replaced the glow plug relay today and still the same issue. I have checked fuses but Im not sure which one it is because the truck came with no owners manual, but all of the 30 amp fuses are good.

I have 12v on the small terminals of the relay when they are tested to ground. When I jump between the two posts I have nothing. Does it matter what terminals are used on the relay. I think I have it correct but since it doesnt start still maybe not. The Napa relay doesnt quite match the OE and has to be turned in order to fit the mounting bolts.

Plugged in the truck and after an hour it started with 3 or 4 attempts but its only in the 30s I shouldnt have to plug in yet should I? Its going to get a lot colder.

Im a novice, this is my first diesel so any advice would be great.

Nov 17, 2011 | 03:53 PM

akorcovelos

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Have you tested your glow plugs? Did you test the old gpr or just assume it was bad? Not being critical, but you will quickly learn with a diesel diagnosing the problem will save you TONS of time and money versus just throwing parts at it.

Nov 17, 2011 | 03:55 PM

powerstroke72

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From: SW Virginia

Moved to the 1999 - 2003 7.3L Powerstroke Diesel forum.

Nov 17, 2011 | 04:19 PM

ajfetterman

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I figure the glow plugs are ok only because with out being plugged in it takes some time but she'll turn over.
I did not test my old GPR basically because it seemed like a common problem and a simple fix. I'm not getting power to the glow plug side of the relay and since it wasn't an exact replacement I'm second guessing the wire position on the relay itself. Can these be backwards? I believe the 2 small terminals don't matter but unsure of the large.
Thanks for your reply and I'm starting to see that diagnosing is a BIG part of owning a diesel.

Nov 17, 2011 | 04:29 PM

nlemerise

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From: AZ

Glow plugs have nothing to do with the engine turning over, but a lot to do with the truck starting (or not starting) in colder weather. You need to ohm out the glow plugs to know if they are alright. If the glowplugs are shot, it won't make any difference about the relay being changed. Try this on the relay...Turn the key to the "ON" position, and go out and jump the two large posts on the relay for about 30 seconds. Then try to start the truck.

Nov 18, 2011 | 08:25 AM

akorcovelos

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there is a good chance your old for was fine. As stated, out need to test your glow plugs, which you can do fairly easily with minimal disassembly. Read through the cold start trouble shooting sticky at the top of this forum, it covers trouble shooting the entire gp system.

Nov 18, 2011 | 09:38 AM

DND58

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From: Carbondale, CO

Welcome aboard. Here are a couple of links to help you troubleshoot further. If plugging in the block heater helps start the truck, sounds like you have problems in the glow plug system somewhere.

https://www.ford-trucks.com/forums/7...pr-system.html

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