Fuel leak

deanrichard · 06-14-2002, 04:50 AM

Dear Porsche lovers,

I have recently purchased a 1974 Porsche 911 which has a problem with the fuel injection system. On tickover fuel is dripping onto the ground from what looks like an overflow pipe from some cannister looking device inside the engine bay (could it be the fuel pump or accumulator??). Shouldn't any excess petrol from the pressurised system be pumped back to the petrol tank? Sorry for not being more specific/technical but I am waiting for a workshop manual and all my experience up until now has been with Minis, Alpines and MGs with carbs.
Thanks in advance for any help on the matter.
Dean- Bilbao, Spain

Kemo · 06-14-2002, 05:15 AM

Post a pic. Welcome to the board.

304065 · 06-14-2002, 05:21 AM

Dean,

Obviously you should not drive the car until this problem is resolved.

Sounds like a leaking fuel filter, although your use of the words "overflow pipe" suggests that you might have an MFI car- and there are four fittings there- three at the top, one at the bottom. Without going into what they do, take a wrench, I think it's a 17mm, and tighten them up. Also tighten the small screw at the top of the console. Wipe everything dry and then turn the key on, the system should pressurize and any leaks should be revealed. Repeat as necessary until there is no fuel present.

Good luck! If you tell me whether your car is Euro MFI that would help with the diagnosis.

Talonz82 · 06-14-2002, 05:36 AM

Hello, please post a pic, I'm not sure if that year came with a vapor recovery tank, a pic would be most helpful, where exactly is it located, is it metal or plastic, how many fittings does it have, of the fittings, which have hoses installed and where do they go?

Jim Sims · 06-14-2002, 06:04 AM

Is the cannister like unit that's leaking silver colored (usually a filter) or green colored (fuel system accumulator)? Some of the accumulators had a third fitting that drained leaking fuel when the internal seals (bladder?) failed. If the leak isn't coming from a fitting that could be tightened then a leaking accumulator must be replaced and of course a fuel filter leaking from any place other than a fitting is an automatic replacement candidate. Cheers, Jim

deanrichard · 06-18-2002, 12:18 PM

Sorry for not replying sooner but my computer crashed.
Trust the picture will help to identify the part.
Dean

Jim Sims · 06-18-2002, 08:45 PM

That's an accumulator; if it's leaking out of the bottom hose it should be replaced as that means the internal seal has failed. Pelican sells them. Jim

Superman · 09:37 PM

That's right. Fuel accumulators have rubber parts that eventually fail and leak gasoline. That's a picture of a fuel accumulator. If it has two high pressure fittings on top that are not leaking, but the unit is leaking at the bottom, then it must be replaced. A low pressure hose at the bottom might be a drain hose, just in case.

I think perhaps your car does not have a hot catalytic converter right under the accumulator, like mine did. Still, hot exhaust is not a good place for dripping gas. I would fix it before driving the car.