I have a 2006 f250 6.0 and over tje weekend it would not start.here is what did.
Friday night rand good parked for the night.
Saturday was going to leave and no start. Checked the fuel filters, wiggled wires under hood, no start.
Sunday un hooked neg. Battery cables, left un hooked for 2 hours. No start
Monday morning leavinv for work decided to try. Fkred right up.
Has anyone had this problem before?what could be causing this? This is happening about every 3-4 weeks since i purchased this truck in February

 

Have you hooked it up and see if it's throwing any codes? Just about any auto parts store will do this for free.

 

Battery itself maybe?

I had bad battery cables on a 99 Expedition one tine; gave me random no start issues. New cables fixed it.

 

Is this a "no crank" problem, or "crank, no fire"?

 

X2 no crank or no fire two totally different problems. Ill go out on a limb and say its a no crank. ALL battery connections need to come apart be cleaned and reinstalled then sprayed with terminal protector. Start there and see if it solves the problem. And I mean clean everything from the battery posts to the solenoid to the starter. Pat attention the the condition of the large cables replace as needed. Pay attention to all grounds. Event he small ones attached to the body. Use battery cleaner on anything thats corroded. Use terminal protector on everything once its bolted back together. If you get no crank after this we'll get you to the next step which is a voltage drop test. Do you have a decent VOM? (Volt Ohm Meter).
Just for he hell of it tap on the starter with a ball peen see if it starts...bad starter.

 

Im throwing a p0401 (egr flow insufficient) i changed the egr valve the first time this happened and it still had the crank no start issue till the next day. Then fired right up.

 

Batteries are good had tested. Cables and conections are clean and tight.

 

Its a crank no fire issue.

 

Get a scanner and post your high pressure oil system readings while it's doing the crank/no start. ICP, ICPV, IPR%, FICMV, and IPW:
https://www.ford-trucks.com/forums/1...l#post16438959

 

X2 need to see fuel pressure etc while cranking. Whens the last time the filters were serviced? Thats a cheap easy thing to do.

 

The fuel filters were changed about 3500 miles ago. I plan on getting a edge cts here in the near future to be able to get readings. Since monday morning I have had no issues with starting. This is why i am baffled why this is happening.

 

If its intermittent it is likely electrical in nature. Look at the pump connector.

 

Crank/no starts are RARELY fuel related on the 6.0. They start and run with half the correct fuel pressure, with multiple injectors failing, and even with mostly clogged filters (see F450+ tank delamination). If it runs fine and has power when it does start, dollars to donuts it's a high pressure oil system problem causing the PCM to not fire the injectors, or if not then almost certainly some other combination of engine management sensors.

When the oil system is having problems it means the engine is literally "getting no fuel" but it has nothing to do with the fuel system itself. The injectors cannot physically fire fuel into the cylinders under a certain ICP, so if the ICPV reading isn't high enough the computer doesn't even try to fire them. Or even if the sensor is reading incorrectly to show enough pressure to where the computer runs the spool valves, actual ICP pressure under ~400psi won't even force open the injector tip open to inject fuel. Then there are several other sensors that if they don't show things like Cam/Crank sync will also prevent the injectors from firing.

You can verify sufficient fuel easily, remove the secondary fuel filter in the engine bay and suck out the fuel. Have someone cycle to KOEO, and the bowl should fill up in a couple seconds. If it does that, fuel should be very far down the list of concerns for the time being.

 

Thank you everyone for the input. Fortunately i havnt had an issue all week. If or when this issue happens again i will be able to get the readings from a scanner.