Ricardo Vega II

Guys, I get the feeling my pump is going out. Noticed that when I strayed the car the pump was making a higher pitched noise, a bit louder humming. Then drove away and made a right turn and then car died. Stopped, put it in park and then started it and then worked fine and has since this past Sunday evening. But now I'm worried that it might be pump, or could be relay? Any way to test it or them?
Thanks
Ricardo Vega II
1987 928 S4 Black

Mrmerlin

how much fuel was in the tank when this happened, how long had the car been driving prior to this happeneing.
The fuel cools the pump so if the tank was low or under 1/4 tank and you had driven say more than 30 miles this gives the fuel time to heat up, then the pump will run hotter and make louder whining noises, try adding 6 oz of MMO to the fuel as well as a bottle of techron

IcemanG17

when my fuel pump died on my S4 it was intermittent.... I tested it like this.....I took resistance between the poles after the car died and wouldn't restart...it was high...like 9 ohms.....once cool the car would run briefly, then die....when cool it was low like 1.5ohms.....

fraggle

Buy a spare and keep it with the car, or just replace it. It's on its way out, and like Mark mentioned, it's intermittent near the end.

Ricardo Vega II

Hey guys, thanks for the advice but I'm kinda confused on which is the actual fuel pump. I see a blue pump outside the gas tank and then I also have seen pics of another pump inside the tank that I can get access thru the top. So which is which and what does each do? I ended up ordering the blue cylinder Bosch pump. Did I get the right one?
Thanks.
Ricardo Vega II
1987 928 S4

Dave928S

Here's the parts diagram showing the main pump, which is in the cradle with the fuel filter, under the fuel tank.

You will then have either an in-tank pump, or a strainer, fitted at the the bottom of the tank. If you have a strainer you will just see a nozzle at the bottom of the tank, with the hose from there going to your main pump. If you have an in-tank pump you will see two terminals (one either side of the nozzle) with wires that go over to the main pump terminals (it runs when the main pump runs).

Dave928S

Here's the main pump, below the fuel filter, fitted with rubber vibration isolators in the cradle ... tank removed.

CAPT Z

The "blue" Bosch pump is fine, but you need to find out if you have another (internal - in the gas tank) fuel pump or if you only have just a strainer (filter) in the tank. Either way, I recommend you replace the external pump (you ordered it), external fuel filter (next to the pump) and the internal (in the tank) pump or filter. I don't know if your car has the internal filter or internal pump. I have a 87 S4 and I don't know what is in the tank in my car, short of actually pulling it out. Maybe someone out there knows which cars have what, by VIN maybe or production date??? If so, please post that info.

Dave928S

Here's a pic of an intank pump (see the terminals) .............. and a strainer (no terminals).

If you have an in-tank pump you will see those terminals, with the wires connected to them which originate from the main pump terminals.

ROG100

Internal fuel pump was not fitted on an 87

Villa22

Petrol cans are an indispensable tool for every driver and are part of the emergency equipment of every vehicle. They help you stay on the road when your tank is empty. If your car runs out of gas, you'll be glad to have such a can on hand.
Petrol cans are not just petrol cans, as they come in many different shapes and sizes

GregBBRD

When the strainer, in your fuel tank, gets plugged up, the fuel pump will complain loudly.
Start there.