My truck , 03 GMC 6 liter, acts like it lost its prime of fuel after its been sitting a little. It has to crank over a while before if fires. Then it will fire right away again unless it sits for a while. Anyone know what would cause this??? Sure appreciate any advice you may have! Thanks

 

Try turning the key to the RUN/ON position (the one right before START), for a few seconds before you start it and see if that helps...

 

odd...it needs a fuel pressure gauge put on it...the pump may have a bad check valve in it

 

check your fuel pressure regulator, make sure its not leakin. if your regulators vacuum fiting points straight out, i've never seen one bad. if your regulators vaccum fitting is at a 90deg angle, take off the vacuum line, if fuel comes out its bad. if fuel doesnt come out, twist it so that the vacuum fiting points down while watching for fuel to come out. if you get any fuel out try replacing the regulator.

second, i've seen a number of fuel pumps on 99and up trucks where the fuel line on the sending unit, between the pump and the top of the sending unit rubs on the springs of the sending unit and eventually rubs a hole through. slowly causes harder and harder starting untill you cant start it, also throws lean codes after its bad enough. easy to see with a fuel pressure gauge, the pressure can bleed off in a matter of seconds.

 

Thanks guys, puttingthe keyin the run position doesn't prime it, I can't hear the full pump charging, I looked all along the lines from the tank and didn't notice a leak. I did lift the truck and maybe something is rubbing somewhere back there. Weirdly enough it started right after I let my son drive it with a friend in the car, They may have taken it over a couple jumps.lol Can you tell me how to find the regulator etc. that you are mentioning? I remember seeing two ( maybe regulators) along the frame.

 

the fuel reg...if an 03 still had 1 serviceable....is on the right side of the engine...its a small pot with a vacuum hose on it...remove the hose and see if gas is in it....you may have to vheck it several times

 

LOL, my brother did that with my dad's Sierra! Jumped a decorative brick bridge in a neighborhood and slammed it so hard it bent the whole front end frame and ripped the skid plate bolt heads off! What an idiot. He didn't even bother to tell anyone. I realized something was wrong when I went to drive it the next day and when I opened the driver door I realized the door and fender were overlapping eachother. There was like a 2 inch gap at the bottom between the fender and door!!! He is a dopehead so that explains everything.[sm=outcold.gif]