Laurent

When I turn the key to the ON position, the fuel pump starts and the pressure builds. ok no prob. I start the engine, run the car a little, turn it off. The fuel pump won't pump when I turn the key back to ON.
is this normal? temp switch or what?

I say this because if I wait and let the fuel pressure drop, it's hard to start... (I have a pressure gauge in the car)

HEYJIMMY911

My car works the same way. I guess if there is still pressure in the line, the pump won't turn on until the pressure is alleviated by injector fire. By the way, what kind of fuel pressure gauge do you have in the car? I was looking into one but never found one I liked. I guess the main problem I ran into was the need for an isolator cable that allowed me to take a mechanical pressure reading, without running a fuel line to the cockpit (major fire hazard.) Anyway, what kind of gauge do you have?

Laurent

Well, you said it, major fire hazzard. No actually I believe it to be safe (of course I don't allow smoking in my car).

I was looking into getting a pressure transducer, the kind you would require to avoid fuel lines. To interpret the signal, you would need ether some data acquisition system (as simple as PC parallel port) or "simply" a Digital display pannel acompanied by a conditionning circuit to manage the signal. Although I'm starting to do that right now, I didn't want to spend that much time on it so...

I got a pressure gauge 0-100 psi. Some nylon (polyamide) 11 or 12 tubing. Be careful, commonly used nylon/polyamide tubing is usually nylon 66 witch will disolve after a while in fuel. I also got a few fittings and a T connector to tap into the control pressure line (from the top of fuel distributor to the warm-up regulator). This is the spot where you get the most info.

If you want more details, e-mail me, I'm currently writing down some modifications I'm doing/I've done...

In the mean time,
Don't fix... improve!
Laurent, 76 911s

ChrisB

Hey guys. Summit Racing Eq. has a digital fuel pressure guage that uses a transducer so you have a much safer couple of wires running into the car's interior. In the event of an accident I hate to think about the possibility of having a pressurized fuel line next to energized electrical wires.

This system has a quick response time and is very accurate.

Chris