My 86 Carrera was left for three weeks in the garage. It started with no problem , but when i had travelled about 300 yards i could hear a noise coming from the back of the drivers side rear wheel arch. It sounded like an electrical whining, when i accelerated the noise would change pitch. After about 2 miles the noise disappeared. This is the second time it's happened, the fist time i could hear a constant clicking coming from the same place but no electrical whine until i turned of the ignition, then there was a short whining for a couple of seconds. Also when i drove the car it stalled a couple of times when i was coming down through the gears. Is this related or just because the car had been left for a few weeks and had not warmed up properly. I would really appreciate any suggestions that anybody has in here. Thanks, Nat

 

What your hearing is your fuel pump. If you are low on fuel it can happen or in many cases it's just a noisy fuel pump. My car has had a noisy fuel pump for 2 yrs with no problems.

 

The fuel pump is mounted on a couple of rubber bushings, to isolate the pump (noise) from the chassis. These are often rotted away = the noise you're hearing.

On the other hand, a noisy pump can sometimes be warning you it is on it's last legs. If you have the correct meter, it's worthwhile to check the current draw on the pump under full load. Should be 15+/- amps. Lacking a meter, inspect the pump fuse block and wiring at the block, for heat damage due to overload. Overload usually signals a dying pump.

 

I believe the fuel pump on an 86 Carrera is mounted on the cross member of the steering rack and not in the engine compartment. Porsche relocated the fuel pumps many years ago due to heat related problems. My 69T and 73S were in the engine compartment, but I don't think the 86 Carrera is located there.

 

Right, it isn't. But if the pump rubber bushings are shot, you could hear the noise throughout the cabin.