Hard Starting

[motorman105]

My 2005 Supercab 4X4 4.0 liter has 112,000 mi. No modifications. Oil changed regularly. I had the 100,000 mile check done and a new fuel filter installed. I'm the original owner.
From the time I bought it new....once I turn the key, it would turn over and immediately start up. A few months ago I noticed every once in a while it would take a few more seconds of turning over to start. Now it takes about 4 seconds of the engine turning over to start and it happens almost all the time. If I turn the ignition to on then wait a few seconds..then engage the starter it starts right up but that doesn't always work. I thought it might be the fuel pump but when I'm driving on the thru-way, the truck accelerates fine. I was thinking maybe the fuel pump relay might be screwing up. I have not had the fuel pressure tested. It doesn't seem to matter if I'm parked on a level surface or not. Could there be a problem with the fuel filter? I asked my mechanic to check it but of course the truck started right up for him every time.
Any ideas?
Thanks!

 

[fordracingfx4]

Did you check your spark plugs and fuel injectors?

 

[jasonl]

I think you are on the right track here. If this is happening more after the truck has sat for a few hours such as overnight etc. You probably have fuel pressure bleed off. Most likely source is your fuel pump. Could be an injector leaking down also, but not nearly as likely. Buy a cheap fuel pressure gauge and hook it up to the fuel rail port. Start it make sure the gauge isn't leaking and then shut it off and see if it's holding pressure. What you're doing now by turning the key to run and waiting for a second you are allowing the sytem to "prime" back up to pressure.

 

[fordracingfx4]

I had the same problem on my Saturn.. Only I changed everything like an idiot instead of looking at the obvious(mine was the pump) but i changed the filters and the plugs, coilpacks, wires, luckily i ended up finding out it was the pump for before i rebulit the whole car lmao

 

[bro2]

I agree with jasonl ,thats what i would do.

 

[Twizzler09]

Sounds like a common case of fpbo (fuel pressure bleed off).

Most commonly, its caused by the check valve on the fuel pump drying/rotting out and allowing fuel to slowly drain back into the tank. Its also possible (and as previsouly stated) somewhat unlikely, that a fuel injector could be leaking. A leaking injector leaves other symptoms that would be noticeable, as well.

jsgeorge: Currently I know of no way to test the injectors at home. Stealerships and well equipped Shops have the tools/machines nessecary for injector testing.

 

[Casto0208]

I think you are on the right track here. If this is happening more after the truck has sat for a few hours such as overnight etc. You probably have fuel pressure bleed off. Most likely source is your fuel pump. Could be an injector leaking down also, but not nearly as likely. Buy a cheap fuel pressure gauge and hook it up to the fuel rail port. Start it make sure the gauge isn't leaking and then shut it off and see if it's holding pressure. What you're doing now by turning the key to run and waiting for a second you are allowing the sytem to "prime" back up to pressure.