Re: loud Bosch fuel pump in 86 Spider Quad?

[Bernie & Diana Bennett <bennetts@domain.elided>]

Brad:

Perhaps crud in your gas tank is putting a strain on the filtration / pumping
system? You didn't mention whether the tank had been cleaned out.

Best Wishes,
Bernie Bennett

Brad Karp wrote:

> I drive a 1986 Spider Quadrifoglio, about 188000 miles on it (with a full
> engine rebuild and new head at 172000 miles).
>
> Two years ago, when it failed to start, the shop I then used replaced the main
> fuel pump, and the car ran well again.
>
> About six months ago, my new shop (Roger's Autoworks in Oakland, CA) noticed
> while doing other work that my in-tank fuel pump wasn't operating. They
> replaced it. I had them replace the fuel filter for good measure, as I never
> have replaced it, and have no idea when the previous owner might have.
>
> Three days ago, as I accelerated uphill, the car stalled and wouldn't restart.
>
> Roger discovered that the fuel pump fuse next to the ECU had melted the
> fuse holder (which I'm told by all is a common occurrence on these cars).
> He removed the bayonet-style fuse holder and replaced it with a more recent-
> style "twin-blade" fuse and fuse holder.
>
> Once he replaced the fuse, the car ran again. I drove home, stopping once for
> gas and once for an errand. About 30 minutes later, when I went to start the
> car, it turned over strongly, but wouldn't start--fuel delivery problems
> again.
>
> I went and bought a new Bosch relay (the larger of the two next to the ECU) for
> the fuel delivery system, as I have heard those often blow. Installed it,
> and the car would half-start, but not "catch".
>
> Took the car back to Roger's. He found that the main fuel pump is
> inoperative; draws 15 amps but doesn't run. Keep in mind that the dead pump
> is only 2 years old, used for fewer than 18K miles. He replaced it with a new
> Bosch pump.
>
> Now the car runs again, as of yesterday afternoon. But the fuel pump is
> quite loud. If I am idling, I can hear the pump whining, and the whine fades
> in and out--it is not a continuous sound. I don't remember it being this
> loud previously (though I did hear it regularly before).
>
> I'm concerned that the pump isn't the root problem; that there's something
> else wrong that will cause me to fry this pump, too (and perhaps more fuses
> and relays...)
>
> Questions:
>
>         1) Should the fuel pump make a droning whine that fades in and out?
>            Again, this is loud enough to be quite conspicuous in the car's
>            interior. Or is that definitely normal operation?
>
>         2) If the whine isn't normal, where should I look for a cause? Crud
>            clogging the pump from either my fuel lines or gas tank? Is this
>            a commonly seen occurrence?
>
> All assistance greatly appreciated! I don't want to kill another $215 Bosch
> fuel pump...
>
> Thanks,
> -Brad, bkarp@domain.elided
> 86 Spider Quadrifoglio, daily driver
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