Fuel Pressure

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Apr 3, 2003 | 07:35 PM

Sorgy

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Joined: Apr 2003

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Fuel Pressure

HI. Really needing help here! I have a 91 f-150 5.0 fuel injected, Dual tanks. Can someone tell me what the fuel pressure should be in the fuel rail? I suspect I have a low fuel pressure problem due to the valves in the tanks. I'm thinking I can pinch of one of the tank fuel lines to stop it from back flowing & see if I get an increase in fuel pressure. It's really running like crap(LOL) Thanks for the help. Sorgy

Last edited by Sorgy; Apr 3, 2003 at 07:38 PM.

Apr 3, 2003 | 10:20 PM

steve83

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Joined: Nov 2002

Posts: 9,987

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From: Memphis, TN

Fuel Pressure

45psi with the FPR disconnected; 35-40psi at idle. The Haynes manual has that and lots of other useful info.

Apr 5, 2003 | 08:18 AM

PigFarmer

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Joined: Mar 2002

Posts: 450

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From: Charter Oak, Iowa

Fuel Pressure

Sorgy,

I'm curious, does your truck happen to have 14# injectors? The 14# injectors have a grey plastic top whereas the 19# units have the orange top. Generally the 5.0 trucks came with the 19# units but there has been some discussion that some 14# units were installed. Steve83 said Haynes showed the fuel pressure to be 45#. This would probably be correct if you have 14# units but if there are 19# units in there then 45# might cause you to run excessively rich at cold-idle and WOT. In either case tho the manufactures spec for your year would be the correct fuel pressure. I wasn't aware that Ford installed some 14# units in the trucks so I gave you the spec for my 89.

Randy