Mr. Dude with a face

I have a 1998 GMC K1500 with the 350 Vortec, which has recently developed a problem where if you jump in the truck and immediately try to fire it up, it cranks for a long time until it starts running. I have found that if I turn the key to the run position for a few seconds and then try to fire it up, it starts immediately, just like it would normally. What do you guys think it is? Do you think my fuel pump is getting ready to go bad? Or is their some sort of check valve that is letting fuel drain back towards the tank? I also think I should note that the entire time I have owned the truck (probably about 3k) I have noticed that after I turn the truck off, the fuel pump keeps running for a good few seconds, which i strongly believe isn't normal. Thanks for any input.

Rednucleus

Sounds like a bad check valve, which I believe is part of the fuel pump assembly. Easy fix is splice a new check valve in your fuel line vs replacing a functioning pump. Never have heard of a pump running after turning off motor.

Mr. Dude with a face

@Rednucleus I wonder if the fuel pump stays running to build up pressure or something, part of the reason I wondered about a bad pump.

Mr. Dude with a face

I just remembered, and figured I should add that within the past few hundred miles I have replaced the fuel filter, and doing so did not change that the pump sometimes stays running. I did this before the cranking issue.

oldchevy

I added the check valve in a 99 Silverado. it worked great and i sold it that way a few years later. This is a cheap way of fixing the problem and much less work.

Mr. Dude with a face

@oldchevy What was your truck doing?

oldchevy

Had to crank for about 10 seconds before it would start or turn the key on and wait for about 10 seconds before trying to start.

Mr. Dude with a face

@oldchevy Cool, i think i will have to look into that.

oldchevy

It wasn't that hard to do and definitely much cheaper and easier than replacing the fuel pump.

Mr. Dude with a face

Ok, good to know, I may just replace the fuel pump anyway because I know they are famous for going out on this era of GM vehicles, thanks for the tip.