924Board.org

[csd]

well the car was runnig fine until,one day i took a short ride and i noticed that the car sometimes during the ride,started like small pulling(like when your out of gas).I came home parked the car and kept it running to take a look at the fuel pump and it was emiting a wierd noise so i turned it off.The next morning i went for an other small ride , it was hard a as hell to start the car ,during,(strated with the small pulls again), the ride the car stoped on a traffic light and i manegd to make it run again, when i came home,i parked,i turned it off and screwd the key to the 1st position to notice if i could hear the fuel pump inyect,and no i can't hear the fuel pump as i turn the key to 2nd position to start the car,cranks but doesn't start an then i hear the fuel pump ,i cheked the fuel pump relay and it's ok,could the fuel pump be jammed?or might there be some dirt that doesn't let the fuel get through,i really dont know what it could be.Any suggestions please i need help on this one.
i also need to know where the fuel pump fuse is according to the tech section on this page it is on the fuel pump relay but i cant find it on my car(my is a 931 euro 80)






[ This Message was edited by: csd on 2001-09-28 03:27 ]

[Smoothie]

I never had this particular problem. It does sound like the fuel pump, but; there are other things that can cause the fuel pump to not run and they're easier to deal with, so might's well check them first. One is the overboost shutdown switch (air pressure checking switch) that's attached to the pressure pipe - just make sure the connection is tight. Also check the connector to the ignition control unit that sits to the right of your right knee under the heater and the ignition module that's mounted on the front of the left wheel well inside the engine compartment and of course check the wires where they attach to the fuel pump to be sure they're tight.

[csd]

i cheked the ignition module ,the vaccum system and the wireing attached to the fuel pump ,it's ok but i can't find that over boost switch,could you please tell me where it's located.And that ignition connector i just can´t find it maybe that euro and us models are different(is it a simple connector or a more complicated thing tell me what it looks like).
I tested the relay and it's fine,the fuel pump is also ok(i tested it with wires direct form the battery)
all i need to check is those things you told me.
i would be very greatfull if you could de more specific about these parts .Thank's

[ This Message was edited by: csd on 2001-09-28 12:01 ]

[larso]

the boost detecting switch is right on the alum. duct in the center that says "924 turbo" on it.

Check out the inside out 2 font. Don't know why porsche did that.

[Smoothie]

If your car has the ICU that I mentioned, it would be sitting on the drivetrain "hump" behind and below the radio. There would be a control line (hose) and an electrical connector attached to it on the drivers side (if the steering wheel is on the left). The electrical connector is rectangular in shape and I would say about 2cm x 3.5cm.

The overboost safety switch is attached to the aluminum piece as Lars said, about 15cm to the left of the throttle body. It's screwed in through the front and has a single wire attached to it.

I just took a look in the parts section of the workshop manual. Actually, you won't have the ICU box I was describing above. Only 1981-82 931s have it.

Another thing to check - my car was running poorly about a year ago. The first thing I thought was it's a fuel problem, but; finally checked and found one of my spark plug connections had corroded. It was pretty bad looking - looked like salt water damage (even though no salt water could have gotten in there). So, it seems too obvious, but; check the distributor cap, rotor, wires, plugs if you haven't already.. (I've found similar corrosion at the base of spark plugs.)



[ This Message was edited by: smoothie on 2001-09-29 02:56 ]