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Fuel pressure too high - how to fix?

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  • Fuel pressure too high - how to fix?

    I bought a replacement fuel pump at AutoZone for about 30 bucks and installed it. The previous owner of my car put in a gauge for the fuel pressure, and now the pressure is too high. From what I've read, I want it between 5 and 6.5 psi. I had a problem with fuel blowing past the needles. Anyway, I'm not sure where to start in lowering the pressure. Can somebody help me out with how to do that?

  • #2
    What make/model of fuel pump did you buy? A stock mechanical fuel pump should not be putting out more than around 6 psi.

    John
    John Pizzi - Squarebirds Administrator

    Thunderbird Registry #36223
    jopizz@verizon.net 856-779-9695

    http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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    • #3
      Thanks for the quick response, John. I think it was branded Duralast, AutoZone's house brand. It was the only option they had there. My old pump was definitely in the normal range on the gauge I have, but this new one has been up as high as 8 at idle.

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      • #4
        At normal idle 8 psi is too high. Most carburetors don't like anything higher than 6 psi. Your only options are to bring it back and try another one or install a pressure regulator. If your old pump was in the normal range then that's not the reason for gas blowing past the needle valves. Are your needle valves rubber or metal. Ethanol has a tendency to harm some rubber parts.

        John
        John Pizzi - Squarebirds Administrator

        Thunderbird Registry #36223
        jopizz@verizon.net 856-779-9695

        http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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        • #5
          Thanks. Honestly, I'm not sure if I've got rubber or metal. I haven't seen, but knowing the guy who put the car together, I'm betting on metal. He would always buy the more durable part if given the choice. Maybe I should try the regulator route. Is that a part I can easily pick up at a regular auto parts store? Anything I need to know about installing it?

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          • #6
            Most new carburetor kits come with the rubber needle valves. If I have metal ones and they are not worn I reuse them. You should be able to get the regulator at most auto parts stores. They are usually used with electric fuel pumps. Before spending money on a regulator I would inspect the needle valves and floats if you are getting too high a fuel level.

            John
            John Pizzi - Squarebirds Administrator

            Thunderbird Registry #36223
            jopizz@verizon.net 856-779-9695

            http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

            Comment


            • #7
              Thanks. I was just looking at the selections at AutoZone, Advance, and Napa. Napa looks like they have dozens of options. I see ones ranging from about $20 up to $180. I just want to get something safe hooked up as quickly as possible. Of courses, I'm not looking to spend more than necessary. Taking the pump back is probably out of the question since it was probably late summer when I bought it and put it in. It looks like my daily driver is going to need some major work, and I'm going to need to get myself to my job.

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              • #8
                If your original pump was putting out the correct pressure then why not put that back in and fix your carburetor. It's obviously not a fuel pressure problem. If you spend money on a regulator you are still going to have the same issue.

                John
                John Pizzi - Squarebirds Administrator

                Thunderbird Registry #36223
                jopizz@verizon.net 856-779-9695

                http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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                • #9
                  I'm sorry. I wasn't clear. I meant the old fuel pump had been putting out the right pressure before it stopped working. I did drive the car this morning, and I didn't have any problems. I stopped a few times to pop the hood, check the pressure, and make sure things looked ok. The fuel pressure was like around 6 psi, so if that continues, I think I'm ok there.

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                  • #10
                    I misunderstood your original post. It sounds like you are good to go. Sometimes varnish can build up around the needle valves from sitting and make them stick and not seal correctly.

                    John
                    John Pizzi - Squarebirds Administrator

                    Thunderbird Registry #36223
                    jopizz@verizon.net 856-779-9695

                    http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

                    Comment


                    • #11
                      Thanks for taking the time to help, John. It is much appreciated. Hopefully, I'm alright. But it is nice to know there are such helpful folks around here when I'm trying to solve a problem.

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