Suddenly my 77 911 developed a massive fuel leak, as in gallons, or at least quarts per minute. unfortunately, I can't determine the source. it appears to be on the underside of the engine, perhaps the fuel line from the tank to the filter? but cannot see the line. Topsides appear dry, does not seem to be coming from the filter, fuel injection lines etc. I'm afraid to start it to see if I can determine the source and don't know where to look. Help?

thanks

 

With the CIS, there are quite a few rubber/plastic lines that could be leaking. The first one I would check would be the rubber one going from the filter to the engine. It is subject to the most movement, and is fairly long. You can lift up on the air sensor plate with the engine OFF and the ignition on to start the fuel pump and pressurize the system. You should be able to find it quickly that way. Just don't run it too long because it is dumping raw fuel into the engine.

 

The line that went first in my '76 was the one from the tunnel to the accumulator. If all is dry up top, that is the one I'd be checking.

 

My '73 has had 2 leaks. Both were found by putting the key in the run position (NOT STARTING THE CAR) to pressurize the lines, and gently wiggling the lines.

The first leak was in the rubber line between the hard line from the fuel pump and the accumulator. The second was in the nylon line off of the fuel distributor to the WUR.

Just trace the lines and the leak will be found.

 

Thanks for the help, found the leak in the line between the tunnel and the accumulator as Dave suggested. Fortunately the flash point of gas was above the temp. of the heat exchanger and exhaust manifold at the time. I was able to repair it but now want to replace all the lines and still cannot find any diagram of the entire fuel line system. I presume the line runs from the tank but it's difficult to trace and appears tied in with a complete bundle of lines. Anyone know of a description or diagram of all the lines?

thanks again-

 

Try Pelican parts (www.pelicanparts.com). They have a section with exploded diagrams. I think they have fuel systems.