fuel leak source?

[Christien]

I've got a pretty nasty fuel leak going on here. I haven't had the car up yet to get a good look, but what are the chances the leak is from the pump itself vs. the lines? When I bought the car and had it inspected (back in early November) I was told the fuel pump was leaking, and it needed replacing. The guy was unable to get one in though (neither he nor I knew about Pelican then) so he put it the old one back on temporarily. It stopped leaking at that point, so we figured maybe it was a loose connection or something.

Anyway, it's leaking again, and badly - probably about 1/2 cup per day, with no driving (getting ready to store it for winter). Normally I'd just replace the fuel pump, but since the inspection I've found the guy was wrong about a couple things, so I'm not 100% convinced it's the fuel pump. What are the chances of the pump leaking vs. the lines? I won't be able to get under it to check it out & fix it myself for another couple weeks.

Thanks.

[Gunter]

Speculation about pump vs. lines is no good. Gas leaks are major fire hazards! Don't run it until you can get under there to see where the leak is coming from. Lift the car, get a good trouble light and a fire extinguisher, take off the skid plate if there is one, make the pump run, check the source of the leak and replace what is necessary. You need to pinch the line when replacing the pump so the gas doesn't run out. If your tank is nearly empty, you may want to clean the screen in the tank if it has one.

[thastings]

Christien,
Gunter is right. The '72 MFI pump leaks most often right at the electric plug. Why????????????
This is work best done out doors, in a flash free area. If you have been reading the various threads on this BBS, I know you have seen these words repeated hundreds of times, but there is a reason for this, GAS FIRES are easy to start and burn super fast.

These pumps are not rebuildable, or repairable by the home garage, or even a shop mechanic. If you have MFI, then the proper fuel pressure p.s.i. to the system is critical. Buy a factory unit from our host ($350+/-) if you can. There are some good rebuilds out there for $100-150, but expect to have to send at least one back for replacement due to psi problems.
It is a good chance that the lines are bad if they are old. Again, replacing them when you remove the pump for R&R, makes it easy. But note the location of each of the 3 hoses. Do NOT rely on the factory and/or aftermarket manuals.
Good luck
Terry Hastings

[Christien]

Thanks for the replies. How dangerous is it to drive with the leak? I ask because I feel unqualified to do this job myself, and would rather get it done properly. I'm a novice (at best) DIY guy - I'm more than happy getting under the car and getting dirty, but I don't want to make things worse, or, worse yet, burn my house down :-)

Chris

[thastings]

A gas leak around hot electrical wires and hot engines is never a good thing. With the spash shield in place its even worse.

If you must drive it to the shop, remove the shield first. If I remember, its only 4 bolts, nothing major. I took mine off 2 yrs ago and have not replaced it yet. Does not affect normal driving on dry days.

If you are not experienced working on gas systems don't try it alone. There is no room for errors.

You have to find out what the problem is before driving the car. The leak is only going to get worst quickly. Then, at best, you are stranded in a car without heat and at worse.........

This replacement is not a big job. The hardest part, other than getting the 30 yr old nut off the bracket, is getting the hoses off the old and onto the new. So a shop does not have to be a P-car repair shop and should need no more that 1.5 hrs to R&R it if they have the new pump in hand. The hoses will be more.

Terry

[Gunter]

It sounds to me that the PO new about the cost of a new pump and did not want to spend the $. But, it may not be the pump. DO NOT DRIVE until you have this fixed. Get to a place where someone can give you an estimate before you start buying parts. A knowlegable Porsche shop can get to the problem quickly. Asking if you should drive with a gas leak is like asking if you should jump off a bridge.

[Christien]

Does anyone have a really clear picture of the area in front of the left rear wheel where the fuel pump is on a 72 T? I'm trying to pinpoint the exact source of the leak before I order any parts, but I don't have the proper stuff here to get the car high enough to get under it (safely) to get a really good look. (I also wanted to get the part # off the fuel pump to make sure I order the right one if that turns out to be the problem.)

Thanks

[Gunter]

A picture from somebody elses car does not pin-point the source of a leak on YOUR car. You are just speculating and guessing. Get the car off the ground and either you, or somebody, has to find the exact leak. If your pump is old and rusty, you will not find a number on it. Any Porsche shop, or Pelican, can get you the right pump but that may not be the problem. Why keep on guessing?

[azasadny]

I went through this same thing this summer and I did a partial engine drop, replaced all fuel lines and clamps from the tunnel to the injectors. I also replaced all vacuum hoses and clamps. Get the hose from our host and clamps from McMaster-Carr and then you don't have to worry. My fuel leak was tricky and difficult to pinpoint until I did the engine drop and saw the gas spraying at the cold start valve.

[thastings]

Once you drop the splash shield, the pump is on the driver side over top of the wheel. It sets on a little shelf with easy access.

There is only one pump for a 72 911 MFI. Do not bother trying to buy a universal or after market pump, they won't work. This is more than just a pump that moves gas to the engine. It does several other things, such as control overflow pressure and gas return functions. These other pumps do none of this.

Without a good jack and stands, you will not be able to get the room to work on this pump, or remove the hoses. Don't suffer, there is a good mechanic's shop around you that can do this in an hr or 2 if they have the pump in hand. This is the easiest pump to replace that they have seen in a long time.

Terry Hastings
If you find that you need replacement hose, take the old with you to the store and have the inner diameter matched at a point where the clamp was.