Fuel Pump

[jchris]

HI all. I am a newish SC Owner (since august '11) and am working through all the car's issues. It's newest trick is an intermittent loud fuel pump. It was loud on a mostly empty tank when i first noticed it. When I removed the fuel cap the was either a a release of pressure or the relief of low pressure in the tank. I have never noticed this before. After the fill up the sound ceased. Later that night I experienced the only hard start I've had before or since. Anyways I'm doing homework on fuel pumps. Has anyone heard of airtex?? Here is the link for what I found. OEM New Fuel Pump Replacement Porsche 911 SC 1981 - 1983

I am know that often you get what you pay for. But sometimes you just pay for a name. Thoughts? This is my first posting to this (or any) board. Please be gentle!!

Thanks, Chris

[dshepp806]

Check your fuel pressures,..aside, get the datestamp on your present fuel pump.

Doyle

[porwolf]

I bought a new, direct replacement, Walbro fuel pump for my 79 SC a year ago for about $50.- on the internet, actually evil-bay. Works fine so far with some elevated noise on occasion though. I don't drive the car very much any more. It may not be as durable as Bosch but for that price I can buy at least three of them. No big deal if it goes. I should get a spare one though, just in case.

[dshepp806]

You sometimes get what you pay for.....sounds like you may have some mechanical failure going on with the cheap pump......hard to say......if using a cheapo,..then definately carry a spare.

I'd get the real deal and be done with it....(should the fuel pump be your actual problem)

Best,

Doyle

['78 SC]

There is a filter (strainer, actually) in the gas tank that can clog and cause the pump to cavitate. This can be surprisingly noisy.

The filter is accessed from underneath the tank. You will need an appropriate tool (do a search for some good suggestions) and a replacement o-ring.

[jchris]

Thanks for the replies! I'll post the results soon.

[euro911sc]

If you do replace the pump there are some fairly high specs to be aware of. Here is the research I did for my SC pump issues:

Debugging:
'82 Fuel Pump issues after rebuild....

Pump Selection:
Interchangablility of Fuel Pumps

I bought my pump from the FLAPS. Its still running great and I have done several track days and street miles on it.

While you are there you should replace the fuel line from the tank to the pump. It rots fast. when replacing the pump put the cars rear end in the air to get the remaining fuel to collect at the front of the tank after you siphon/pump as much fuel out as possible.

Good luck!

-Michael

[lindy 911]

You should not hear the sound of escaping pressure or vacuum when taking the gas cap off. Check the vent line to make sure it's not clogged. Drive the car with the gas cap loose for a while and see if the noise doesn't go away. If it goes away with the cap loose you know you have a clogged vent.