Dies then won't crank

[02stroker250]

Ok 02 f250 will crank and run till it gets hot. Then it dies and want start back for about 30 to 40 mins. I've replaced the cps with 2 different new ones and they will not crank it but I can put the old one back in there and it will crank and run for a lil while


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[strokemyego]

i'm no expert on 7.3l but i have seen a few, known problem to cause a short to the pcm. usually either the ebp sensor, or the fuel heater.

[NoRalPh]

OK, first thing,,, PCM problems (like shorts) don't "fix" themselves. If it runs again after a cool-down, something is changing.

What does "crank" mean to you? Crank like running or Crank like turning over on the starter?

How's your oil? Are you overdue for a change? What weight oil are you using?

The CPS is a good start, but it sounds like you're covered that

What about fuel? As soon as it dies, open the yellow lever (water drain) on the fuelbowl and see what comes out of the drain tube (pass side, metal tube against the motor, over the ft tire). It should run out of there with at least a cup of fuel.

SES light been on at all?

Is your truck chipped? If so, remove it as a test...

How many miles on the engine?

There's a start!

[02stroker250]

Oil is good. And I've checked the fuel bowl twice after it died. And once it dies it will spin over good just acts like it doesn't fire. Oil is 15w40 rotella


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[02stroker250]

And tried removing the chip and no change that and the cos was the first thing I tried and no ses light either


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[02stroker250]

Oh and it's got 232,000 miles on it


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[strokemyego]

absolutely with the shorts, haha electrical fundamentals, absolutely correct, but at the same time shorts can get heavier when the truck is hot. hot wire is more resistance in the wire which will cause voltage to seak a path to ground that has less resistance... but i think your right, haha listen to him and disregard me

[NoRalPh]

Here's my thinking, something is "repairing" itself as it cools off and the HiPres oil system, and it's controls, would be the first place I'd look into. Either the oil gets hot, and thins, causing a drop in pressure (because it's only working marginally now) to the point where it's below the threshold for running. Or it's old oil that's foaming-up and causing the drop (the reason I ask about the oils condition).

Neither seems to be true here, so the pump could be marginal because of its age or the pressure is being bleed-off as stuff gets hot. But either of these would start to happen gradually. You'd notice problems on long, hot trips first. Did this start happening all of a sudden?

If so, that could indicate one of the HiPres oil sensors failing (ICP or IPR). These sensors are expensive so, you don't want to just "try" changing them The ICP is pretty easy to test. Next time it won't restart, just unplug it. The PCM will see no signal coming from it and set a default value for the IPR to use as a "limp-in". An indication of a failing ICP is that, as the internal seals fail, they leak engine oil into their electrical plug so, look for sings.

The IPR has no free test like that though. What can happen with them is that the "tin nut", that holds the coil on to their shaft, can vibrate off and that coil moves around causing problems with its readings. Also, the plunger inside can get crap in it and stick (you can try "rapping" on it with a screwdriver handle sometimes). It is also possible to, carefully take it apart and inspect. It not uncommon for a failing IPR to do what you describe.

Both these sensors have moving parts that heating up can cause to bind. The very Best way to check the function of both these sensors is with the proper scanner. It would quickly tell you if they were doing their job or not. Unfortunately, you need a professional scanner or an AutoEnginuity because our trucks are not, strictly, OBD-II and the parts stores "generic" scanners are of little use.

[02stroker250]

Ok here's a update I changed the oil and filter. Didn't change nothing. Then I had a brainstorm I put the chip back on it and it ran fine for about 2 hours I rode around on the backroads by my place.

It ran perfect the whole time. Then I thought well maybe that was it. So me and the wife decide to take my truck out tonight get About 5 miles from home it just dies like turning the key off.

So I got out and unplugged the icp sensor to try that didn't make a difference it just span like crazy. No smoke or anything coming outta the exhaust.


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[02stroker250]

Bump!


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