fuel pump fuse / relay trouble, '86 Spider Quad

[Brad Karp <bkarp@domain.elided>]

In the past two years, I've had both the main fuel pump and in-tank fuel
pump replaced in my '86 Spider Quad.

This morning, as I drove out of my driveway and accelerated uphill toward
work (or so I thought), the engine lost power. I depressed the accelerator
more, but the RPMs still declined, and I stalled. Coasted to the side of the
road, and while the engine cranked very strongly, it wouldn't start.

I took the car into Roger's Autoworks. Roger found that the in-line fuse for
my fuel pump had melted the fuse holder! He replaced the fuse holder and
fuse, and my car ran well again.

I drove home, and stopped twice on the way. Both times, flawless starts.

Then I reached home, left the car off for about 20 minutes, and returned to
the car. It stalled as I pulled out of the driveway. Exact same behavior:
turns over very strongly, won't start.

I removed the rear carpet piece behind the seats. I pulled the new fuel
pump fuse, and it looked good. Put a continuity light on it and it *is* good.

Suspicions: I've either burned out the fuel pump relay, or the fuel pump
itself (which is < 2 years old!) is frying the electrics that supply it
(drawing too much current?).

I did a search in the Digest archives, and there's one suggestion along the
lines of a bad ground inside the ECU causing repeated relay failure. Is it
possible this may have caused both my fuse failure and whatever failure I'm
now encountering (fuel pump relay being the main guess)?

Can anyone with experience with these L-Jetronic cars tell me if the bad
ground explanation is the most likely one, or if there are other avenues
worth investigating?

I can try to tell Roger (and Chris) about the fix in that old Digest note
(run a new ground, splice into either wire to terminal #85 on the fuel pump
relay), but if any of you know Roger, I'm not sure if he'll listen to my
amateur theorizing...

Thanks!

-Brad, bkarp@domain.elided
86 Spider Quadrifoglio, daily driver (but not today :-( )
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