Thread: Fuel pump down
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Bob Kontak Bob Kontak is offline
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Join Date: Nov 2007
Location: North Canton, Ohio
Posts: 14,593
Fuel pump down

After backing into the problem, my pals 89 930 has a fuel pump that will shut off intermittently. I think we have fixed this but we wish to run some data past the group.

Recent symptoms over last month, car warms, runs a little rough and emits black-ish, maybe a speck blu-ish smoke but does not stink like either oil or rich.

Today, both of in car, running an errand, car warms up fully - 85 outside. . Grocery store stop for 1/2 hour, car in sun.

Leave grocery store, within a mile or two, car hiccups and dies. Farted around poking stuff and looking at engine. A couple of minor attempts at firing from residual pressure then nothing.

Finally my pal asks "What about them fuel pump relays I got in the glove box?"

Replace both relays and we see the #6 fuse is cooked (Pump one and Pump 2) . Replace fuse. Runs like a champ for two hours. No smoke, no rough running, nuttin.


When one fuel pump goes bad what causes the smoke? Is it unburnt "stuff" because of a lean mixture?

What would cause the fuse to blow given the car ran "fine" recently with one fuel pump taking a nap. (we did find inconsistencies on the outside windings of on old relay - hoping this was the root cause)
1981 911SC Targa
Old 06-15-2014, 02:00 PM
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