924Board.org

[newbie924]

Hi Guys, I have a 1978 model Porsche 924 which I have been tickering on for some time, finally it was ready to be tested and taxed, yet on the day it was to be taken over to the testing station the car started cutting off after about 2 minutes running well. there seems to be some noise coming from the rear pump or rear fuel pump if one is found there, the car restarts after cutting off with no difficulty but then cuts off again after a few minutes.. Any ideas before I start looking for new fuel pumps etc or switching the system to a weber system.

[scm924s]

There is no need to change from the Kjet system, it works perfectly well if properly maintained.

You don't state whether your car has previously been in continual use or has been standing for some time. I am not sure whether your year of car has 1 single external pump, or has passed the changeover to 1 in tank and 1 external pump, however a noisy pump is usually on it's way to failure.

If the car has been out of use for some time you need to clear the fuel lines and change all the fuel filters, possibly draining the tank.

if you have only one pump, there should be a filter inline between tank and pump which prevents rubbish entering the pump, it will almost certainly be choked if the car has been out of service for some time. The main filter is on the LH inner front wing

The K jet system does not like being stood for any length of time, and needs a perfectly clean fuel supply.

persevere, it's worth it.
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[924-76]

Agree with all the above.

Is the fuel pump noisy right away on start up or noise increase as it's running until it dies?

As mentioned above the pump might be on the wait out or if the fuel tank has debris/rust in it, it could be clogging the line, forcing the pump to work harder (noise) and engine dies of fuel starvation.

1-Inspect the tank for debris/rust. Drain and clean as required.
2-Change the pre-fuel pump filter.
3-If the above didn't solve your problem and you still have a noisy fuel pump, test power going to the pump and test pump pressure fuel output.
_________________
1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP

[newbie924]

We have changed the rear fuel pump which had no effect since the old one was good, plugs, plug high tension wires, coil, spark distributor inner parts, cleaned the tank and all the way up to the fuel distributor, changed fuel filter and still the car wont start,, I am starting to noticed that the previous owner must have tampered with the cold start stuff since certain items are not visible were they are supposed to be, also the previous owner has fitted a push switch which I was told I had to press a few times before starting but still no luck. Fuel is getting to the fuel dizzy and injectors,,, Im seriously thinking of going to webbers now.