2002 won't stay running...
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Cargo Master
Joined: Jul 2005
Posts: 2,311
Likes: 367
From: Kansas
2002 won't stay running...
2002 7.3 automatic, last time I was at the farm, the glow plugs weren't working. Spent a little bit of time testing and determined the glow plug relay was never receiving a ground signal from the pcm (for whatever reason). Have been shorting across the 2 lugs on the gpr relay for 30 seconds before getting in the cab to start it when its cold. Recently that seemed to stop working...but by accident discovered if you leave the 2 lugs shorted together with a jumper cable clamp while cranking, the engine will start...BUT as soon as you remove the jumper cable clamp, the engine shuts off.
I've spent quite a bit of time working on Powerstrokes over the years but don't recall anything except the glowplugs on that circuit leaving the glow plug relay. Getting ready to reinstall the factory service manuals to take a peek at the wiring diagrams, but thought I would ask here if anyone knows what might be causing this...obviously that circuit isn't required to be hot to make the engine run assuming everything is "normal"
I've spent quite a bit of time working on Powerstrokes over the years but don't recall anything except the glowplugs on that circuit leaving the glow plug relay. Getting ready to reinstall the factory service manuals to take a peek at the wiring diagrams, but thought I would ask here if anyone knows what might be causing this...obviously that circuit isn't required to be hot to make the engine run assuming everything is "normal"
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Cargo Master
Joined: Jul 2005
Posts: 2,311
Likes: 367
From: Kansas
turns out when shorting the two main posts of the GPR, the booster cable clamp was also providing power to the switched power connector of the GPR. It troubleshooting, the switched power on the GPR, IPR, and Manifold air intake heater relay was only showing around 8 volts (battery voltage was 12.5). pulled fuse 22 and checked it with an ohm meter and it was good. Still had low voltage with all those components unplugged. pulled the 42-pin connector apart to check for corrosion, it was clean, and PIN 24 only had 8 volts. went back to fuse 22 and check both sides with a voltmeter, once side had 12, one side showed 10.5...replaced the fuse and voila, 12v on both sides of the fuse...the fuse had blown but apparently left enough carbon (or whatever) to make the fuse pass a continuity check, but couldn't actually flow any current.
as a bonus, replaced the GPR and the glow plugs work again.
as a bonus, replaced the GPR and the glow plugs work again.
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swimlvr591
1987 - 1996 F150 & Larger F-Series Trucks
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Sep 6, 2010 12:49 AM
