Casey_SS

For a while now, my car hasn't wanted to start on the first crank when cold and I think it has something to do with the fuel pump / pressure. I have an in-car fuel pressure gauge and am running the Racetronix pump with the wiring harness, meaning that power is supplied straight from the alternator. Alt and battery are both in good shape, meaning they're putting out the voltages they should (12 on the batt, 13.5 on the alt.)

What seems to be happening is that the first time I put the key to the "on" position and prime the pump, pressure only comes up to 20psi and quickly drops to 5-10 and stays there. If I turn the key off and then back on, it shoots up to ~50 -60psi but eventually starts falling if I don't start the car. Once the pressure is up there on the 2nd prime of the pump, car starts fine and there are no pressure issues / fluctuations, etc. while the engine is running. Always get ~40 at idle & 50 - 55 with no vacuum / WOT conditions. No driveability problems or weird behavior whatsoever when it's running...

This only happens on cold starts - on warm starts the pressure is always there. This isn't really a "problem" per se, as pressure is always where it should be on the 2nd turn of the key but I find it weird and would like to at least understand the dynamics of what's happening and decide whether or not it's worth "fixing".

To that end, I've searched and found several references to a "check valve" in the fuel system that's supposed to control fuel flow back to the tank - this seems a likely culprit but would be a pain in the @ss to fix and doesn't seem worth it when I always have correct pressure on the 2nd turn of the key. Any other problems a bad check valve can cause if I leave it alone? Any other possible culprits to consider?

TobyZ28

My car is similar too, unfortunatly I dont have a guage in the car to check whats going on. Mine seems less likely to start when warm (after sitting a couple of hours). But 2 primes and its usually just fine.

A friends car is doing exactly what yours is doing. The strange thing is that I had a new pump installed maybe 2 years ago, and my friend JUST had a higher lph pump put in this year.

I really would like to figure out what's going on. We both have new fuel filters too, my car just had cleaned injectors put back in and the problem still persisted.