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Fuel Pump?

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Old 09-09-2009, 05:35 PM   #1
Join Date: Oct 2007
Posts: 16
Default Fuel Pump?

I have spent a lot of money on this stupid car and am getting very frustrated. I am on my second Walbro 255 fuel pump and I think it is bad. At idle I am running about 39 psi with the vaccum line off fpr. What is the pressure suppose to be? Before this I thought I was too rich because I have 42 lb injectors in it. When I take the second pump off the rail the car getts no gas from the walbro 255 pump. But when I put it back on I get gas. How is that possible? Is there another 255 pump for the 2.3 turbo or should I just go back to the factory pump in tank and run two pumps? Please help I am lost.

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Old 09-10-2009, 10:35 AM   #2
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Well when you do the Walbro conversion you're supposed to just take the chassis mounted pump off. After you remove the chassis mounted pump then replace it with a fuel filter or some fuel line and ground the resistor wire from the chassis mounted pump (search around SVOCA for better instructions). That could be the root of your problems, because if you didn't ground that resistor wire I imagine that the Walbro just won't pump when you take the chassis mounted pump off. Here are a couple of threads that kinda detail what you need to do:


'65 Mustang GT-stroker 347 w/Toploader 4-speed
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Old 09-11-2009, 07:54 PM   #3
mg man 75
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May want to also check for kink fuel line. A buddy in KY just found a problem in his was a kinked return line. It was hide under a piece of rubber hose. Thought that might help someone else. I spent most of a day with him. We solved a bunch of issues but he found this one on his own.
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Old 09-15-2009, 07:09 AM   #4
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If you haven't done the resistor wire mod (84 and 85 SVO only) then you are burning up the pump. It will not pump fluids correctly either.

FP should be 39 w/o vacuum to the regulator.

There is no reason that you cannot have adequate fuel supply by using the dual pump setup. It actually will deliver more fuel at more than adequate pressure than that of the single in tank pump. It has already been proven.

BTW, you are going to run too rich with 42lb injectors unless you have a J chip or a stand alone system.
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Old 10-24-2009, 03:55 PM   #5
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Ford says 38-42psi at rail with out vac attached is in spec. you need to run what ever is stock for the eec you have(injectors to ecu). you have aftermarket LOW impedance 42# injectors? high impedance will eat your injector drivers.
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Old 10-24-2009, 03:55 PM
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17, 23, 255, 84, 89, cyl, fuel, grounded, jumped, location, mustang, psi, pump, resiter, svo, swap, wire

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