Need help with air leak

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Nov 10, 2011 | 07:43 PM

86sixbanger

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Need help with air leak

I just got an 89 250 4x4 7.3 with a ZF 5 speed. It has an air leak problem while running on the rear tank. When running on the front tank it runs awesome, except for a possible problem with losing fuel prime from sitting overnight. The injection pump is pretty much brand new. So what I'm wondering is where in the fuel system, and at what should I be looking for my air leak at? I'm thinking somewhere close to the rear tank..?..Thanks in advance......

Nov 10, 2011 | 07:53 PM

dieself250

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From: NC

What is the truck doing? How much fuel is in the rear tank. It could be a broken pickup in the rear tank, a bad fitting between the tank and selector valve, or a week lift pump.

Nov 10, 2011 | 08:10 PM

86sixbanger

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Rear tank is full. On the rear tank once in awhile it will sputter and then surge while driving, and even stall out and die sometimes

Nov 11, 2011 | 01:38 PM

starmilt

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From: Faibanks Ak.

If it runs fine from the front tank, except for fuel leaking back overnight, you have two problems.
One will be somewhere from the fuel selector back to the back tank.
The bleeding back will be some where from the lift pump to the return lines. The return line o-rings being the most common.

Nov 12, 2011 | 12:42 AM

86sixbanger

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For the rear tank problem, could it be the in tank pump, or would it not get any fuel if the pump was defective???

Nov 12, 2011 | 03:56 AM

tjc transport

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From: Marlboro Mental Hospital.

no in tank pump on these trucks

Nov 12, 2011 | 10:36 AM

86sixbanger

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Sweet thanks so it's gonna be a line somewhere in there, and then maybe later on down the road I could replace the lift pump with an electric one? thanks