Fuel Pressure Problem
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New User
Joined: May 2002
Posts: 9
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Fuel Pressure Problem
I have a 1991 F150 4X4 with a 302 engine.With a fuel pressure guage installed on the valve on fuel rail I get 15 sometimes 20 psi with koeo or with engine running. This is the reading I get for the back tank.The front tank gives me a steady 30 psi.Truck will not run on back tank. Need help locating problem.
Postmaster
Joined: Jul 1999
Posts: 3,172
Likes: 4
Fuel Pressure Problem
The FP for the rear tank is in the tank correct ? Other than the conventional fuel filter , I think there is also a filter in the module that switches the tanks , check it to make sure its not clogged . Other than that Id say the rear FP is just about dead . If your truck has been in an area with lots of road salt then before you condemn the pump check the FP connecter for the FP , I saw one last week with one wire severly corroded that was causing an intermittant no start on a single tank / single pump 1990 model . The Fuel Psi was fine when running . Its easier & cheaper to replace a connecter than a FP .
Senior User
Joined: Feb 2002
Posts: 258
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From: Allegan Michigan
Fuel Pressure Problem
Food for thaught. According to Haynes the fuel pressure KOEO for a 4.9 should be 50 to 60 PSI and KOER 40 to 60 PSI All others should be 35 to 45 KOEO ans 30 to 45 KOER. I thaught that the 30 PSI sounded a bit lo. IU would start with the fuel filter, then the electrical connections, then the high pres pump. Changing a tank pump is not fun or cheep. My thaughts are try to get that front tank up to normal operating pres. first and I think your back tank will start working.
