Geomyster

I'm usually able to figure out my woes via previous posts and Google, but I have not yet found my answer.

After my truck has been sitting at least a couple of hours, it has trouble starting Unless I turn the key to the run position for 5 seconds to let the fuel pump pressurize the system, and then crank the motor. If I do not let the key sit in the run position for 4-5 seconds to let the fuel pump pressure up the system; then the engine will just turn over as if it doesn't have any gas for 3-5 seconds. -Once it starts the engine sputters for another 1 or 2 seconds.

If I start it up right after it has been running (within 2 or so hours) then it has no problem going directly from off to the engine firing up.

It has never done this before, and just started about 4-5 days ago.

There are no problems at any other time - still plenty of get up 'n go while I'm driving, no stalling.

I thought it might be the fuel pump slowly starting to fade on me and lose pressure, but the fella at carquest seemed certain that the fuel pump wouldn't be doing that. He suggested that it was probably something else causing the system to lose pressure while the truck sits. -Perhaps the fuel regulator? (I'm not real familiar with the fuel regulator)

I haven't noticed any fuel leaks anywhere.

Any advice on what it could be, or where to start troubleshooting?

shamrock246

what year and engine?,sounds like the fuel pressure is bleeding off probably the pressure regulator


Sean

97 4x4 burb

Geomyster

It's an '02 with a 5.3.
I replaced the fuel pressure regulator, and that wasn't the correct answer
It's getting worse, so I'm going to prolly nut up and replace the fuel pump here within the next day or so.

Chuzz

How many miles are on it and do you ever let the fuel tank get near empty before filling up? In tank pumps are cooled by the gasoline on top of them. If you're in the habit of running it low regularly, this could cause premature fuel pump failure. Have someone do a pressure test on the fuel system and see if the pump is holding pressure. If not, then there's your most likely culprit.

Geomyster

For people that find this thread in the future:
Fuel Pump. Fuel pump is the correct answer.

Note to Chuzz: No, I always top off when my tank is between 1/4 and 1/2 full. -And it's not just to keep the pump submersed and cooled, the more fuel in the tank the less condensation will occur within the tank during the winter months.

Also, as far as diagnosing goes, the fuel pump itself had not failed - apparently there is a check valve of some sort in the assembly that had failed.
-I saved the fuel pump (new and old are both Delphi's) so that in the future if something like the sending unit or pump goes out, maybe I'll try to patch one with parts from the other... $270 for a pump sucks, glad I'm not tard enough to pay a dealership $1000 to do it.)