i have a 97 camaro 350 t56 that just seems to be hard to start at first. it takes about three turns of the ignition to get the engine running. this morning i had time to check the fuel pressure and im not to sure what it suppose to be at when the ignition is turned on but jumps to about 10 to 15 psi then drops down toward 0, that is on the first crank of the engine as well. when i crank it a second time it jumps a little higher but then drops towards 0 while keeping the ignition on after each crank. the third time it jumps higher then decides to start up. I swapped out the fuel pump relay and it still did the same thing. I just wanted to know if the pressure is suppose to stay constant when the ignition is on and if anyone had any thoughts about what it could be before changing out the fuel pump. thanks

 

Check the vacuum line coming off the FPR, easy 3 second check. If it is wet, or smells like gas, the FPR is broken (fuel pressure regulator). It's a small black hose going into the passenger side of the manifold.

Second test, while cranking, floor the gas and see if it starts. Second way to do this is take the 4 bolts of the fuel rails and lift the fuel rail up. Prime the car, and see if any injectors are leaking.

Third thing, your pump is shot and needs to be replaced.

Pressure for my car was around 42-45 primed, 38 idling, and 50-52 at WOT.

 

sounds like bad fuel pump. I would have to turn ingnition on and off about three
times before it would start. would prime to 42psi and as soon as pump stopped primeing would drop to 0psi. changed pump and now starts first try all the time.

 

The fuel pump has a check valve to maintain pressure at the fuel rail for starting (fuel pressure should be 41 - 46 psi with the vacuum line removed from the fuel pressure regulator). It's common for this check valve to get dirty and stick open, causing th fuel pressure to bleed off qucikly, causing hard starts.

 

It would be very unusual to see 50-52psi at WOT on a stock fuel system - and that's outside of GM spec. GM spec for acceptable pressure is 41-47psi, with 43.5psi being the "correct" presssure. With the engine idling, pull the vacuum line of the fuel pressure regulator. That will indicate the pressure you are going to see at WOT. But you still have to actually run it at WOT under max load to see if the pump is capable of holding that pressure.

 

i am having these same problems after i installed the walbro pump. it got worse and worse over a few days. so i took the pump out, looked it over. nothing looked out of the ordinary. so i put back together. well the car started normal for about a week. now it is slowly getting worse.
sometimes it will start right up, others i will have turn the key over 2-3 times, then it will be good.

what does this sound like? TIA