hubturn

'95 Cab. Fuel pump makes a loud buzzing noise. When turn ignition on, not all the way to start, it will buzz for 5-10 seconds and then shut off. You can touch it and feel it vibrate. Audible all the time the engine is running. It wasn't always like this. Shot? Thanks.

Rusty Spokes

The 5-10 seconds the fuel pump runs when you turn the key on is normal..it primes the fuel loop for a better start.

The loud buzzing noise is odd. You have the super big rubber boot that fits over the fuel pump intact? If so..you really should have a hard time hearing the pump run.

Fuel filter recently replaced?..I ask as if the fuel system is restricted the fuel pump will become noisy. They also get noisy when the pump gets towards the "end of life"

I replaced my fuel pump at 100K miles..it was still very silent..my thinking is 100K is good enough.

Here is a youtube of the replacement showing that big boot on the fuel pump.

hubturn

Thanks Rusty. I was counting on you to give me the straight story. I'm going to disassemble this all tomorrow and check it out. I knew about the initial priming and always heard the pump a little bit, but this is really loud. Who knows, maybe there is a piece of debris in the pump. Might as well do the filter while in the business.

CRAZY_RUSSIAN

replace your fuel filter if you haven't done so in the last 40k. replace the fuel pump if you don't know how old it is, also grab a new gasket for the fuel pump. and as rusty mentioned, 100k for the pump is plenty

hubturn

So I crank it up this morning - no noise. Yesterday was a hot day and I drove it for about an hour. 114K on this pump - original. I'm going to replace the filter and re-evaluate, but I'm thinking the pump is going out. A lot of pumps out there. Any better than the others?

Rusty Spokes

There are two possible Bosch fuel pumps. The difference is the inlet side of the pump where the hose clamps on. Should be a 15mm inlet..or could be a 12mm inlet.

Bosch pump 69436 has the 15mm inlet.

Bosch pump 69433 has a 12mm inlet

The 69436 is about $100 new..shop around. I got mine from Amazon.

Those threaded electrical connectors are a little longer than the original Bosch pump..the connectors work fine but don't compress the "O" rings like the OEM Audi. I used some dielectric grease to waterproof the connectors.