Buick Riv fuel pump issue still continuing saga

New pump a couple weeks ago and the folks are very reluctant to put another pump in but I think I have ruled everything else out except a faulty pump again.

Twice the pump did not start and had power at the test connector. Swapped relays, computer, etc. Only way I got it to start was to bang on the tank with a hammer two different times. Seems to me that if banging on the tank started it, there is nothing else except a bad pump.

I want to be reasonable but these guys have had it four different times and do everything except warrenty out the pump. Anything else it could be?

Here’s details. Car wouldn’t start, no fuel pressure, etc. Towed it in. Replaced pump with Delco, and harness in tank and sock filter etc.

Next day stalled but re-started right away three times. Ran a new wire and ground from pump to computer.

OK for a couple weeks then didn’t want to start at gas station after 50 mile commute and filling it up. Finally started. Next day wouldn’t start at all at station but BANGED ON THE TANK and it started right up.

Back to shop. Dinged around and replaced fuel filter and said it was plugged. Next day at work (50 miles out) wouldn’t start. BANGED ON TANK AND IT STARTED right up. Back to shop. Couldn’t find anything wrong but swapped computers.

I agree a computer or relay or filter or wiring etc. could be a problem but not with these symptoms when you bang on the tank and it starts. Its in the garage now and I’m reluctant to use it since not sure how many times you can start a stalled pump by banging on it. I’m kind of stuck staying with these guys since I already paid for it.

Watcha think? Bad pump?

Perhaps bad mechanic? I have two GM’s and am able to hear the pump “whirring” for a couple seconds when the key is turned on without starting the engine. If pump does not initially “whir”, but then “whirrs” when you bang the tank, I suggest bad pump or bad electrical connections where the pump is connected above the tank.

One simple thing you can do to see if the pump is getting voltage but not running is to replace the fuel pump fuse with a current test meter. See how much current is drawn when the pump isn’t running. If the shaft is hung up the current will be high, perhaps around 12 to 15 amps. I would guess normal current would be around 4 amps. The shop could do this test easily to see if the new pump is bad.