92spi

hey guys, how long should my 2001 4.3l Silverado 1500 be holding fuel pressure? as it is, it's only about 90 seconds from about 52 psi at idle to 0 psi. cranking pressure is about 60. feel like I'm having a leak inside the upper intake. maybe press regulator? gimme somethin' to go on here; thanks ahead.

tech2

yes, it should be holding pressure longer than 90seconds. it can only be leaking:
-back to the tank....which would cause a long crank condition after a long cold soak
-fpr into the manifold...which would cause a hard restart flood condition when warm
-injectors into the manifold...which would cause a hard restart flood condition when warm
-externally from a fuel line

oldchevy

Probably the check valve in the fuel pump assembly is bad.

92spi

so I guess it's pop the upper intake and look and smell for leaking fuel? then on to the fuel pump? can't see any external leaks, and the truck seems to run alright.

tech2

why don't you try clamping off the fuel lines first. it would be much faster diagnosis. there should be a rubber length where it comes off the frame rail along the trans.
pull the vacuum line off the fuel regulator and check for fuel Do the easy stuff first ...just saying!
both these things are much more common than leaking injectors. chevy injectors for that gen rarely have problems, unless someone touched the o-ring seals, even 14years later.

92spi

thank you much for posting. I'll have to get a manual to see where these components are located. truck doesn't get driven much, and I'm pretty ignorant to it's ways and means. I did change the fuel filter when I started to have trouble starting it. like maybe it was flooding. I can see where the fuel supply and return enter the plenum, but I thought the regulator was underneath it. be doing some researching this wkend; thank you again for posting.

92spi

well, got back on the project this am. pressured up fuel rails, clamped off supply to engine and no more fuel pressure drop. this tells me the check valve in the fuel pump is bad, yes? just after I filled up the tank! guess it's a fuel pump changeout. got any suggestions for supplier?

oldchevy

You can add a check valve in the fuel line to fix the problem without having to drop the tank. It worked great for me. If you want to change the fuel pump, get either a Delco or Delphi pump. They are more money but well worth it. They last longer and with the labor involved you don't want to do it again a year later. The cheap off brands usually don't last long.

92spi

i surely would appreciate more info on this 'mod'. dropping the tank or lifting the bed isn't on my list of fun jobs to do.

tech2

cycling the key to run for 2 seconds and repeating multiple times (to prime the fuel pump) will allow the truck to start normally.


the one way check valve is spliced into the fuel feed line as close to the tank as possible. fuel in the line before the valve will still drain back but the fuel rail will still be primed. cut out a section of the fuel line where its accessible, before the filter may be a good spot. splice it into the fuel line in the correct direction.


the kit may come with the hardware or you may need to buy either fuel hose and clamps or compression fittings.