1991 740 regina...with only ONE INTANK fuel pump...How can I check voltage to fuel pump with pump installed and engine running ?

my first clue is the engine is running. no volts, no fuel, no run. NOW, if you have a fuel pressure problem and suspect a voltage drop, then you have to pull the sender. i know, the car won't run. but, the wiring in the epoxy passthrough on the fuel sender breaks down and will cut voltage down or off in the tank. check voltage at the trunk connector and compare it to the reading at the fuel pump. good luck, chuck.

If you pull the carpet away from the LH side of the trunk, you will find the harness that runs to the pump/sender. The heavy guage pink wire is the positive feed to the pump. You should also find a disconnect in the vicinity of the LH trunk lid hinge which makes for a good place to tie in a volt meter.

Its the pink heavier gauge wire but the strange thing is I tapped into it with my voltmeter but did'nt read a thing ..i will try again tomorrow...this while the engine was running