Noisy Fuel Pump/Accumulator Question
 

Sometimes when I start my 190E 2.3, there is a strange noise coming from the fuel pump location. When I start the engine cold there is no noise. When I turn the key on when the engine is hot, the fuel pumps operate for a second or two and they sound normal. But, sometimes when the engine is hot and I start the engine, there is weird grinding/grumbling noise that's hard to describe and it last for maybe 10-15 seconds then goes away.

Since the noise goes away, I don't think the Fuel Pumps are causing the noise. I was wondering if a faulty Fuel Accumulator could cause this.

I'll be checking it sometime over the next few days, but I was just curious if someone else has experienced this problem.

Thanks,

Dave

From another site: "Often times the noise you hear can be a droan or a moan which is caused by a faulty fuel accumulator. It's a component that maintains constantpressure in the lines. It can either be leaking fuel or the inner diaphragm spring could be broken."

Fuel accumulator:
The fuel accumulator maintains the pressure in the fuel system for a certain time after the engine has been switched off. When the engine is running it serves to deaden the noise of the electric fuel pump. After the engine has been switched off, the fuel accumulator maintains the pressure in the fuel system in order to facilitate re-starting, particularly when the engine is hot. The design of the accumulator housing is such that it deadens the noise from the fuel pump when the engine is running. The interior of the fuel accumulator is divided into two chambers by means of a diaphragm. One chamber serves as the accumulator volume for the fuel, the other chamber contains a spring. During operation the accumulator chamber is filled with fuel. This causes the diaphragm to bend back against the force of the spring until it is halted by the stops in the spring chamber. The diaphragm remains in this position, which corresponds to the maximum accumulator volume, as long as the engine is running.

Could you describe the noise further?

In last...2months I have noticed a strange noise coming from my fuel pump area. It sounds like a "static" type noise and gets noiser when I let off the throttle...I have pretty good hearing and when I let the car idle and listen where the fuel pump area is -- It is definitely coming from there.

Also, can a fuel accumulator get clogged over time and restrict fuel flow?