Running issues when gas is below 1/4 tank

General E28 FAQs.
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rexmo
Posts: 1149
Joined: Feb 12, 2006 1:00 PM
Location: Missouriopolis

My car stalls and won]t re-start when fuel level gets low

Post by rexmo »

Problem: My car stalls and won't re-start when the fuel level gets below about 1/8 tank.

Cause: The fuel pump in the tank (Suction device with pre-supply pump per ETK) is weak or not operating at all. It is thought that letting the car run out of gas damages the pump, since it is lubed by fuel. If it is running, a buzzing noise should be audible when trying to start. A better test for this is to rig a jumper for the fuel pump relay, preferably with a switch, unless your arms are long enough to reach the ignition switch while your ear is near the floor of the trunk.

Solution: Best is to replace with a new one. You might find a good used one. Some owners report making a ca. '71 Vega pump work, with an hour's worth of hacking.

Sometimes such pumps can get stuck, especially after the car sits for an extended period of time. Tapping the pump with a hammer may unstick it.
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