Buzzing fuel pump?

[Tommy Z]

There is now a constant buzzing under the pedal cluster of my 79' SC from what I assume is the fuel pump. I heard it once or twice over the summer when ambient temps got high. Today in my part of Florida we hit 88 degrees and the pump whined and buzzed all the way home. Almost sounds like a seat belt buzzer but not quite. Is this an indication that the pump is starting to fail and I should plan on replacing soon? I couldn't find any record of the pump having been replaced and I have about 127k on the clock. Cooler air temps don't seem to cause the buzz but hot days are coming soon. Any advice would be appreciated. Is it a fairly basic repair for a newbie? Anything else I should consider updating while I'm there?

[jlex]

Is there an insulator between it and the bracket that maybe is deteriorated? Take a look...

[Glenfield]

Tommy, I had a very similar thing happen on a road trip earlier in the year. T’was the fuel pump. Replacing it also was good reason to replace the check valve which, turns out, was the cause of a few cold hot start issues. Too tricky to do on side of the road but otherwise looked to be very routine.

Trying to find the exact fuel pump I bought bc there are some QC issues with some of the options. I’ll try and track it down but you may have better luck searching the forum.

[Tommy Z]

Thanks Glenfield. In looking at the options from our host it sure would be preferable to go with the Bosch option for pump and check valve vs. the genuine Porsche option to save $300. I would be interested to know which one you and other members might have used.

[targa80]

You will need to jack up the front and remove the large bump plate to have access to the fuel pump. You will also need to use vice grips and some protection while crushing the rubber fuel hose coming from the fuel tank. It is not a hard task but again you are messing with fuel lines and the pump puts out about 90 lbs of pressure so test it all before closing up. Pull the fuel pump relay and use a jumper with a momentary switch between 87a and 30 on the relay socket. Turn ignition to on and hit the momentary switch while watching the location of the fuel pump. No leaks from the test, button it up and your ready to drive.

Made this momentary jumper switch back in the early 1970’s when I bought my first car and had starter issues. The momentary jumper switch allowed me to hit the starter solenoid while working on my car and not needing anyone to turn the ignition key. I have used it multiple times over the past 50 years to help me troubleshoot electrical, mechanical and fuel problems.