fuel pressure question
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Joined: Mar 2003
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From: woodbine u.s
fuel pressure question
whats up guys. I have a friend with a 1991 f-150 with the 5.8 engine. he has been complaining of poor fuel mileage lately so i told him to bring it over. I installed a pressure guage on the fuel rail to check it out and when he cranked it up it jumped to almost 100 psi. unplugging the vacuum did not affect it any. could he have a bad regulator or what else could make the preesure jump so high. any help is appreciated.
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Joined: Dec 2001
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From: Louisville,Ky.
That ot the return line is highly restricted somewhere.
It should have around 32# at idle and 38-40 with the regulator vacuum line unplugged.
Somewhere in the return side, there is a too much restriction.
If it has dual tanks, it is possible that the switching device on the frame is not shifting properly and is restricting flow.
Jimmy
It should have around 32# at idle and 38-40 with the regulator vacuum line unplugged.
Somewhere in the return side, there is a too much restriction.
If it has dual tanks, it is possible that the switching device on the frame is not shifting properly and is restricting flow.
Jimmy
