suspect fuel filter or pump

Phil Rose pjrose at
Wed Aug 6 14:03:14 EDT 2003

At 9:10 AM -0600 8/6/03, Lou.Martin at wrote:
>Got stranded on the way home last night; lost power, engine quit, electrics
>ok, tried starting - fired up but quit.  Towed it home, tried starting -
>fired up for couple of seconds, then quit.  Put it out of mind for the night
>(too many problems cropping up recently).
>I'll consult the Bentley tonight, but a few hints would be appreciated.  Is
>there a separate fuel filter?

Separate from...? The only fuel filter is that very large, aluminum
can situated near the right (passenger) rear corner of the engine
compartment just aft of the air (filter) box. I believe the change
interval on the fuel filter is 30K, but some advise annual

>  When does the pump start running, should I be
>able to hear it.

In the '91 200q, the fuel pump operates only while the engine is
cranking and/or running. So you can't hear the pump by merely
switching on the ignition--as is possible with earlier models. During
operation, the fuel pump can be so noisy (buzzing) as to be
distinctly noticed over the idling-engine noise, but a good pump
should be too quiet to hear very easily. I'd imagine that even a
noisy pump might not be heard very easily while cranking--unless you
hold your head directly over the pump while a helper tries to start
the engine. A high level of pump noise is often a prelude to pump
failure, which is not uncommon on cars with over 100K miles.

Besides a plugged fuel filter or dead pump, consider the fuse and the
pump-relay as possible causes. Also the fuel pressure regulator, too.
Did you recently fill the gas tank (possibly with contaminated fuel)?


Phil Rose
Rochester, NY
mailto:pjrose at

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