98 Chevrolet Silverado 5.7L Vortec - Five fuel pump check valve failures?

I put a new fuel pump on my brother's 98 Chevrolet Silverado 5.7L Vortec. The pump that came off was itself a replacement. So here is the story. I checked his fuel pressure which was erratic so we replaced the pump. It seemed to work fine for a month or so and then it wouldn't start or was very hard to start and sometimes we could shoot a bit of starting fluid and it would start. He didn't want to tackle it again so he took it to a repair shop run by a very good friend of ours. Another new pump was installed. This is two pumps. Same thing again, Third pump, Same thing again. He said it is not a pressure problem, it has correct fuel pressure when it's running, it's just difficult to start. Now he, the repair man, says it is a check valve problem within the fuel pump. If he replaces this pump, under warranty again, it will be pump number five! I have difficulty believing four new fuel pumps have had defective check valves. I personally have no diagnostic tools except a fuel pressure gauge, which I bought just to check my brother's fuel pump and a VOM. I was going to suggest to my brother to purchase an auxiliary electric fuel pump but our question is would he have to remove the current pump? Or would the aux pump pull fuel through the current pump? This vehicle is used only on the farm but it needs to be able to start and run because we feed cattle daily and have other work going on as well that the truck is used for. Can anyone give us some direction here? Thanks!

Have you checked for GOOD power and ground, at the fuel pump(s)?

Have you verified that the fuel pressure is in fact bleeding off? If you install the gauge, get the truck running normally then shut it off, how quickly does the fuel pressure drop off?

Have you verified that fuel pressure is low during the crank no start/long crank/hard start condition?

IF this truly is a fuel bleed off issue, then there are other ways for that to happen besides the check valve in the fuel pump. The regulator at the intake, for example. It can be allowing fuel pressure to drain back to the tank, or even allowing it to drain into the intake. :silly:

This video might help.



And if it does turn out to be the pump check valve again then an inline fuel check valve is the cheap and easy way to fix it