Humpty
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- South Dakota, USA
SOLVED!
Updating for the benefit if anyone else who may encounter this or a similar issue. What ended up being the culprit was injector lines 5 and 6 were reversed at the injector pump.
Firing order being 1,8,7,2,6,5,4,3 essentially cylinder 6’s fuel was getting blasted onto 5 prematurely.. collecting on the glow plug and eventually burning off, roasting the glow plug.. even with the glow plug completely disconnected from the glowplug controller.
I’d been told that by the previous owner that the pump had been “rebuilt” but then the truck had sat for a couple years afterward. I didn’t think to check the lines just because I assumed since they were custom bent that you couldn’t hook them up wrong. Evidently you can.
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M998A1 with 6.2, i’ve now replaced 4 glow plugs on the same cylinder.
A popular theory was that the injector was leaking and dripping fuel onto the glow plug. The normal heating cycle of the glow plug was igniting the glow plug and roasting it.
I replaced the injectors with cheapo import injectors.. melted another glow plug. Thought, well, that’s what I get for buying cheap injectors.
I replaced the cheap injectors with Delphi injectors.. melted two more glow plugs.
Start box is operating normally. I’ve metered the glow plug lead to verify that it’s not sending power non stop or anything weird.
Exhaust has a greyish smoke, smells of unburnt diesel. Truck otherwise seems to run fine.
Is it possible the Injector pump is sending too much pressure down that line? Would “turning down” the fuel at the pump be a possible option? Or is this perhaps just a timing issue?
Any thoughts or suggestions appreciated!
Updating for the benefit if anyone else who may encounter this or a similar issue. What ended up being the culprit was injector lines 5 and 6 were reversed at the injector pump.
Firing order being 1,8,7,2,6,5,4,3 essentially cylinder 6’s fuel was getting blasted onto 5 prematurely.. collecting on the glow plug and eventually burning off, roasting the glow plug.. even with the glow plug completely disconnected from the glowplug controller.
I’d been told that by the previous owner that the pump had been “rebuilt” but then the truck had sat for a couple years afterward. I didn’t think to check the lines just because I assumed since they were custom bent that you couldn’t hook them up wrong. Evidently you can.
————————
M998A1 with 6.2, i’ve now replaced 4 glow plugs on the same cylinder.
A popular theory was that the injector was leaking and dripping fuel onto the glow plug. The normal heating cycle of the glow plug was igniting the glow plug and roasting it.
I replaced the injectors with cheapo import injectors.. melted another glow plug. Thought, well, that’s what I get for buying cheap injectors.
I replaced the cheap injectors with Delphi injectors.. melted two more glow plugs.
Start box is operating normally. I’ve metered the glow plug lead to verify that it’s not sending power non stop or anything weird.
Exhaust has a greyish smoke, smells of unburnt diesel. Truck otherwise seems to run fine.
Is it possible the Injector pump is sending too much pressure down that line? Would “turning down” the fuel at the pump be a possible option? Or is this perhaps just a timing issue?
Any thoughts or suggestions appreciated!
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