fuel pump question
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fuel pump question
does a '92 7.3l diesel have two electric fuel pumps, one in each fuel tank, or does it have one fuel pump on the frame. are these in addition to the mechanical injector pump on the engine or does it just have the mechanical injector pump? also, where exactly is the injector pump located? is it physically inside the engine driven by gears like the oil pump or whatever or is it outside the engine driven by the serpentine belt like the a/c compressor or alternator?
reason i'm asking, i was driving the other day i had a little under 1/4 of a tank and i noticed when i came to a stop and let the engine idle it would fluctuate. it would rev to 800rpms then go down to 400 or 500 then rev back up to 700 or 800. it was pretty quick, like every second it would shoot up then back down. i switched to the rear fuel tank, which was full and it smoothed back out. then after a mile or so i went back to the front and the symptom never came back.
i think i've had trouble with the front tank in the past but it has been at a lower fuel level and i was parked on a hill.
reason i'm asking, i was driving the other day i had a little under 1/4 of a tank and i noticed when i came to a stop and let the engine idle it would fluctuate. it would rev to 800rpms then go down to 400 or 500 then rev back up to 700 or 800. it was pretty quick, like every second it would shoot up then back down. i switched to the rear fuel tank, which was full and it smoothed back out. then after a mile or so i went back to the front and the symptom never came back.
i think i've had trouble with the front tank in the past but it has been at a lower fuel level and i was parked on a hill.
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Joined: Apr 2008
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i dont think they had electric, my 91 has a mechanical on the engine and the IP (injection pump) is in the valley of the engine in the front. it is gear driven, i have only had that at low fuel.. thats what it sounds like to me, the guage may not be accurate.
Posting Guru
Joined: Sep 2007
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From: Las vegas
No electric pumps from the factory. It uses a mechanicle lift pump on the side of the engine and a swiching valve by the tanks to controll wich tank it pulls fule from. Sounds to me like your pick up tube in the front tank is cracked. useualy hapens around that level.
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Joined: Aug 2007
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drop the tank and remove the sender you will most likely find the fuel pickup (plastic) has desentigrated and is ingesting air when the tank is below half tank
the metal line ends a few inches above the bottom of the tank
the metal line ends a few inches above the bottom of the tank
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