I've got a 2001 F150 with 5.4L engine. Got in it this am and it just wouldn't start. Has been sitting for about 4 days but ran fine before. Had this problem one other time and couldn't make any headway on it then after about 6 hours I got in it and it just started up. It's turning over fine and the gas rail on top of the engine has pressure on the port but it doesn't seem to want to catch. Any suggestions as to what it might be or where I should start checking? Where's the port for the OBD code reader? Know it's under the driver's side dash but am unable to find. Is it covered? Thanks for any help.

 

Getting an engine to run isn't very difficult if you think about it in a simplified manner. You need ignition, fuel, and air.

Pull a coil, stick an old spark plug in it, crank the engine over and verify you've got a bright, crisp blue spark.

Verify you've got fuel pressure - 5 psi will put fuel into the rails, but it won't be enough to run the engine, so you need to verify fuel pressure with a gauge. Most gauges have a tap to draw fuel from the system as well, so you can check fuel quality. A quick and dirty trick is to try spraying a little ether or carb cleaner into the throttle body and seeing if the engine will start and run. If it runs and quits almost immediately, you've got a fuel system concern.

And air goes without saying, make sure you've got an unrestricted airway into the engine - no critters making nests in the airbox or anything goofy like that.

The DLC is on the driver's side of the dash, almost directly downwards from the little storage bin below the shifter.