need help with fuel bleeding off on 97 k2500
 

I just bought a 97 k2500 with the 5.7 and it acts like the fuel pressure bleeds off becuase when you start it it doesnt start right up unless you turn the key on and off a couple times to cycle the pump then it starts right up. Someone told me there is a rubber line or diaphram right under where the return & pressure lines go into the intake or throttle body there are 2 bolts that hold the lines down I havent unblolted them yet but wondering if any one has ever heard of this. I just put on a new fuel filter because it was frozen with water.Any help would be greatly appreciated.
Thanks in advance :bang:

Check the fuel pressure regulator too. After that then stick an FP gauge on there to see what the pressure is... prolly 38-48psi or so at Key On. You may have a bad intank pump...

the pressure regulater is what the parts store thought too. I looked up the parts under the lines and the reg. was the only thing under there unless there is a rubber line on the return side of the reg. that is cracked. how do you know if the reg. is bad just by replacing it? Also is the reg. just under where those two lines are bolted down to the throttle body? thanks again for your help!

This sounds like the check valve in the fuel pump has failed. My brother's 1998 chevy blazer was having the same symptoms you described, I changed the fuel pump assembly and it has been working fine ever since.

Fuel pressure regulator failure on these engines is very common. A quick check is to remove the throttle body or the vacuum fitting with the brake booster hose attached and look down inside the plastic upper intake. If it is wet with fuel then replace the regulator. You will have to remove the metal fuel line(8mm and 16mm at the back of the intake, and 10mm hoddown) then disconnect the wires and pull the upper plenum off. Also the regulator has no vacuum line. One way to tell if it is the regulator or the pump is if it a regulator it will likely misfire when started and a bad pump will not. Hope this helps.

I also think this may be your problem. I have seen numerous mid 90s GM cars have the symptoms you describe and putting in a new fuel pump fixed it every time.

Take a pair of vise grips, or similar, and pinch off the return line where it is braided behind the manifold. Then use a pressure gauge to see if it still bleeds off. If so, fuel pump. If not, regulator. LS1Nova is all over it. You need to remove the top plenum as the reg is under it and just open to the plenum referance vac.

Sometimes when the fuel filter gets clogged it puts undo stress on the pump and burns it up. My vote goes for the fuel pump being bad. When they start going up, they will surge like that. You may soon feel it when you are trying to accelerate like to get on the highway or go up a hill. Sooner or later it will leave you.

I work in a garage and 9 times out of 10 its the fuel pump.

use L82gofasts trick with the visegrip. The only problem with shotgunning a pump in there is that they are a couple hundred bucks and a fuel regulator is cheap. Check the cheap and easy things first.