Perrier

I could hear with key in position 2 a sound which lasts about 4 seconds more like the whirring sound of a pump. I'm told this is normal and I think it is the fuel pump making the pressurizing.

Some said they hear nothing.

Question: is this whirring sound indicative the fuel pump is nearing replacement? Or a brand new fuel pump shouldn't generate any sound?

ron m.

The best way to check fuel pump health is to check fuel pressure. I don't know what that is necessarily. A noisy pump isn't necessarily an indication of a bad one... but a pump that changes pitch as it's priming the line may mean it's ready to go (happened on my other car, which stalled on me).

Perrier

I am not concerned about the fuel pump - car runs perfect; engine silky smooth in acceleration.
I am only curious where this noise coming from. Somebody told me it's from the pneumatic systems...the PSE...that in older car models there is really such buzzing sound, when key was in pos 2 and lasting only 4 seconds. Any one has any idea what mechanical device in the system triggers this sound?

ron m.

So, if you didn't care about the pump, then why were you concerned about pump failure in the first place? Fuel pumps are tricky little buggers... they may seem fine one day and be dead the next. Does your car start immediately after turning the ignition?

I have replaced an inline pump on a W124, one for a Miata and another one for a full sized van and I could hear the new pump units prime the fuel line at the accesory position (number 2) of the ignition.

Good luck.

Perrier

Yes my car does start immediately the past 2 weeks. 2 weeks before, there was an intermittent start delay in the form of prolonged cranking lasting about 7-8 seconds but mysteriously this never happens the past few 2 weeks. This leads me to suspect the sound that I hear at pos 2 is not from the pump but from the PSE...the pneumatic pump.

ron m.

Perrier, prolonged cranking would indicate a failure of the fuel pump to prime the line and supply adequate pressure prior to starting. This could also be an intermittent problem that becomes worse when it's hot outside (vapor locking). How many miles do you have on your car?

Perrier

Ron, only 46K KM done to my car. The past 14 days very hot here @ 31 degrees celsius, but never happens once a second of prolonged cranking.

surenmunoo

Can anyone please help me, im new here, i got a w210 1997 e280, i had a bit of rat problem, sorted out all cables but car still does not start, cranks, wants to start but doesnt, if i put fuel directly into the manifold it starts and rev up but not starting on its own, any help would be appreaciated.

Ps, when car is cranking must the injectors pulse or does it pulse after starting,

Thanks in advance