Low fuel pressure?

[artw45]

95 Ranger 4.0 new fuel filter and air filter, cranks for a long time before starting, then starts right up after you shut it off. Left key on for 20-30 seconds and it starts right up. Weak fuel pump? Or is something causing it to be slow coming up to pressure?

 

[Roert42]

Could be leaking pressure back into the tank.

If you turn the key for a second, then off and on a couple of times, then try and start it does it fire right up?

 

[artw45]

Yes, turned on for a couple seconds then off and back on a couple times then hit it and started right up.

 

[Dirtman]

Yes you're losing fuel pressure, most likely from the check valve at the pump.

 

[RonD]

Fuel pump only runs for 2 seconds when you first turn on the key, its a safety thing
So leaving key on past that 2 seconds doesn't do anything to fuel pressure

As said, turning the key on and then off 3 times would give fuel pump 6 seconds of run time, that would be about 30psi, you get approx 10psi in each 2second run

1986-1997 Rangers have 30-40psi fuel pressure when running
After shutting off the key that pressure should hold at 20psi for MONTHS and MONTHS

If it doesn't then in the 1986 to 1997 Rangers it could be the Fuel Pressure Regulator(FPR) on the engine
Or, as said, the check valve inside the fuel pump

You can remove the fuel line from the FPR and cycle the key on and off one time to see if its leaking fuel, it shouldn't

1998 and up Rangers used a different system