Help Needed 02 f-250 won't fire

[offroadjpg]

My first time on here. I have a 02 f-250 4x4 7.3. For about 6-8 months have had an intermitent problem with it starting. Only happens when engine warmed up. It will crank but will not fire. If I wait a few minutes to sometimes an hour it will start right up and run perfect. It has no pattern,sometimes once a week,sometimes once a month,no consistency. Yesterday it quit on me in traffic for the first time,and wouldn't start back up. Had it towed to a dealer and when we unhooked it it started and ran perfect. It shows no codes,and cannot find any obvious loose or broken electrical connections. It is getting fuel. Has anyone had this happen to them?

The only mode to it is a Hypertech programer set mild.

Thanks.

 

[Tail_Gunner]

Sounds like a Cam Position Sensor possibly. When those things go bad, it can cause an intermittant running condition like you've described. There is a recall for the the CPS. A dealer under the recall should replace it free of charge. If that fixes it. great. If not, continue looking for other causes.

The next thing I'd check are the wire harness connectors Under the Valve Cover. There is a double ended connector that is part of the valve cover gasket. The main harness plugs into one side, the UVC harness plugs into the other end under the valve cover. The UVC part is notorious for coming partially or totally apart. It's been enough of a problem that Ford came out with a little plastic wedge that inserts into the connector to lock it together.

 

[Frankenstien]

I think the CPS will throw a code when it starts to go stupid... I agree with Kent ... the UVC is a possible cause, however when it starts to have issue its usually associated with a rough idle... since you state this most often happens when the truck is warm it would consider taking a peak at your IPR sensor. located Drivers side, near the front of the head, Valley side. next time the truck fails to start, go out and tap the sensor lightly... retry starting.. if she fires then you have your culprit. Good luck and let us know the out come,

 

[Frankenstien]

From a buddy of mine.. "Hot start issues are traditionally oil related. Cold oil is thicker, and builds pressure faster and will even build pressure against a leaky o-ring to a point.

Hot oil is thin and runny, and if there is an internal oil leak like an injector o-ring, or one of those plugs thats on the inside of the valve cover, you would never see the leak.

It would prolly be a small leak, just enough that your starter motor cant spin the engine quite fast enough to build pressure when its hot, but once the truck is running, the RPM's are high enough to overcome the leak.

Id get it hot, shut it off, try to restart and monitor the ICP pressure. If it doesnt get to 500psi to start, then you've got a weak pump or a leak. "