The fuel pump in the 86.5 928 has become much much louder as of 3 hours ago and now the car will not rev past 3000 rpms. From the reading I have done when a fuel pump gets louder its probably about to kick the bucket and when the revs wont go above the 3000 the LH ECU is about to kick the bucket.

My question is can the LH ECU failing cause the fuel pump to have the symtoms of being louder then usual or can the fuel pump play any part in the car not reving past 3000.

Im going to test the fuel pump on its own later in the morning after the sun is up.

Heres hoping its not both items going down the drain .

(Fixed typo)

 

Oh, so *you* have the "last 928".


Gut feeling is the fuel pump is the primary cause of your woes. What's the likelyhood of two simultaneous failures? Knock on wood.

 

I think you should follow the symptoms of the fuel pump, the ECU is probably fine. I believe the ECU indirectly controls the fuel pump via relay, but its either an "on" or "off" scenario.......no "variable" control. So if the fuel pump is noisy, it's either getting ready to go, or there is some other type of obstruction causing it to be loud.

Fuel filter replaced?
Tank clean?
Tank vented properly?

 

Well the fuel pump is noisy as hell running it on its own, so im assuming its about to go.

The reason i asked about the ecu is due to the 3000 rpm mark of engine choking.

 

I agree with the previous posters, check out the fuel pump first. If it is noisy it also could be due to a clogged fuel filter.

Pull the metal plate down from the rear of the fuel tank. Jumper the pump to be turned on (between pins 30 and 87 of the pump relay) and feel the pump. If it is making grinding sounds there is probably a mechanical problem with the pump.

The LH for 85 to 86 model 928s doesn't suffer the hybrid failure problem because it doesn't have one. It does control the fuel pump.