orcfromthesouth

Searched for noisy fuel pumps. I gather that it needs attention. I am almost sure its the fuel pump and not a AC fan. Its a humming noise coming from the front. Moreso when cold.

Is it serviceable? My 993 spent some time sitting around and I suspect the pump is probably in need of a clean-up. Or should I change for a new one?

Thanks

JasonAndreas

A noisy fuel pump can still operate just fine so before you spend several hundred dollars to replace it (I've never heard of them being serviceable?) you should measure the fuel pressure and delivery rate on the left side fuel rail. The only special/generic tools required are a pressure gauge, some plastic tubing and a short piece of wire (to jumper the DME relay).

orcfromthesouth

Thanks Jason.

I have no operating problems whatsoever. Its just that I thought the noise could be the first warning of impending failure.
By service I mean taking the electric motor and cleaning the contact brushes (not sure that's what they are called).

kdurg

Orc..

I replaced my fuel pump about a month ago. The noise heard from inside the cabin became progressively worse over several weeks. The stealer said it could continue to operate fine for months but sooner or later it would fail. They did not offer repair as an option.

Not sure about a '94 ROW 993.....but a '96 US 993 uses the DME Relay to power the fuel pump. As the pump begins to work harder/fail, the DME Relay runs the risk of frying prematurely.

Rick Lee

I've been through this on my Carrera and my SC. Anything post '83 uses the DME relay to control the fuel pump. So to test it on my Carrera (after I got stranded in the middle of nowhere in 90 deg. heat with nothing to drink and waited 3 hrs. for a tow home), I straightlined the fuel pump fuse from the hazard fuse, since it's always hot. That made the wire get all orange hot and the fuel pump started coughing and stumbling. I replaced it and all was fine. In the SC it made a whirring buzz and I decided I would pre-empt its failure. Installed new fuel pump and car was noticeably more quiet.

orcfromthesouth

A stealer not offering to repair something and wanting to sell you a new part instead?? Never heard that one before....LOL
I am old school and still believe most things just need some attention or replacing a few wear items. Will check the service manual. I suspect the pump is a sealed unit, and thus non-serviceable.
I have ordered my DME relay spare per reco's from this board. Will take a look at how hard it is to access the pump.

TomF

The pumps are not serviceable. I would replace it if it is getting noisy. I concur with Rick that it is not worth getting stranded. A failing pump will start to eat relays for lunch as it draws too much current. Keep a spare on board even with a good fuel pump.

Rick Lee

I doubt fuel pump R&R is any easier on a 993 than it is on earlier 911's. So once you get the tank drained or pinched off and get the fuel pump out, you won't want to do this job twice. Drop the money for the new pump and be done with it. Even if you're lucky enough to be able to plan for this job and run your tank down to almost empty, draining a few more gallons out is no fun at all. If your pump goes out with a full tank, you'll have a real problem on your hands. When I did my Carrera, I was running around, looking for pickle barrells and buckets to hold all the fuel I had to dump. Not fun! This is also a good time to replace the cheap braided hoses to the pump and put on new hose clamps.