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Blue smoke out the hood vents, fuel pump quit.. Opinions??

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So I start the MJ and get about ten feet when it acts like it ran outta gas. I start cranking it over and it sputters and dies. Next I see a little blue smoke rise up thru the hood vents as I am cranking. I deduct that the fuel pump isnt running when the keys on so I run a hot wire to the pump from a constant 12v circuit and it starts hummin and home I go.


Once home I am lookin for melted wires, relays, etc and find nuthin. Scratch my head and go to the store in the XJ, but when I get home I notice a bad noise under ITS DAMN HOOD! I take a look and it looks like the water pump bearings going out on it now. GEEZUS!!!!!


2/3 of my fleets down now! Anyway today I am looking for an orange wire that feeds the fuel pump on the MJ and the one I find is connected to what I believe is like a ceramic ballast resistor mounted on the drivers side inner fender and the resistor disintegrates in my hand when I remove it. Inside its black and toasted. Guessin thats the problem but I wonder if something else made it fail or it was just old and ready to die?


What is that thing and what role does it play? Its Sunday so I can't get one till tomorrow anyway.




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:waving: Hiya Rick!


IIRC, the ballast resistor only plays in when you start the truck, and thats about it. Once you release to the "run" position, I think its bypassed. Someone will have to confirm this.


Other than that, if I was in your situation, I would start by replacing the ballast resistor and the offending wire, and go from there.


Rob L. :cheers:

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WASSUP ROB?! :thumbsup:


Well I repl'd the resistor but no luck. Even started to smoke that one. The wire back to the pumps good I metered that, but the other wire vanishes into a mass of wiring that I've no clue where it goes from there.


This is yet another in a long line of problems lately that are making me think "SELL THE P.O.S.!!" :wall:

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Hi Rick! :waving:


Rob has it backwards. the resistor is bypassed upon startup, and then after a couple seconds power is diverted through it. This gives the pump full power for startup, then cuts back on the power for running (originally it was supposedly a way to quiet the pump down). If only the resistor is bad, the truck should start up, then die after a second or so.


It sounds as if there's a short in the system. :dunno: Both wires might be toast by now. look for any wires that might be touching the exhaust. If you've already got a wire in for power, you're halfway there. now just add a switch and you'll have an antitheft device. :D


water pump should be the easy too. :thumbsup: I did one in under an hour while stranded in a rest area parking lot. :banana:

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