Car hesitating to start... Please help

[Jlandry287]

So here's my problem:
Every morning when I go out to my car, I turn the key and have to hold it from 5-10 seconds. The car will "crank" but not "fire" and it just got back from the mechanic, it wasn't spitting any codes so it was unfixed. Occasionally once it finally starts it will rev up to 1,000rpm then stall. When I turn the key to start it again it will [usually] start with no problem. Also if I turn the car off and run in a store (less than 15min) and come up, it cranks right up.

I've been reading a lot of forums and a lot of people are saying it could be either:
a) fuel pump
b) fuel filter
c) fuel pressure regulator

If more details are needed let me know!

 

[phucheneh]

It often helps to know what kind of car we're talking about.

It sounds very much like you are losing residual fuel pressure. Barring any external leakage, there are three possible sources. From most likely to least likely:

Torn diaphragm in a vacuum-operated fuel pressure regulator

Bad anti-drainback valve in the fuel pump

Leaking injector

You can confirm the general issue by putting a fuel pressure gauge on it and letting it sit for a few hours. You should be able to run the car with the gauge hooked up and see somewhere in the realm of 30-40psi, depending on the vehicle. It should hold that pressure when you shut it down. A small amount of initial leakdown is sometimes normal, but the pressure should stabilize. You'll likely see a slow, continuous drop over a period of hours. Occasionally, especially with a fuel pump issue, the gas will dump out of the line immediately, causing the pressure to rapidly drop to near zero.

You can check the regulator by pulling the vacuum line off and checking for gas. There should be none on that side of the internal diaphragm.