Got this 6.0 f350 2004. When I bought it was told that needed new hpop. Replaced hpop, but it back together, no start kept getting no commo with ficm. Replaced wiring harness, both of them. Put it on the ford computer, showed pcm and ficm was bad, replaced them. Truck will now start within four seconds cold. But will not start after warm up. A little shot of starting fluid and fires right up. Ford told me lpop must be bad, but pressure does not drop. Am replacing lpop.
Any one have any suggestions? I have had one code about not com with glow plug mod. But it does not show up all the time. If it was in glow plugs it would not start cold, would it not?

 

Throwing parts at it is not the best way to resolve this issue, lets diagnose what is actually wrong and fix that ok?

4 seconds seems like a long time to get it going. If your low pressure oil pump was bad, the truck wouldn't start at all. Typically when a 6.0 starts fine cold but not warm, it's a high pressure oil leak. You can verify this a couple ways. First is with a scanner, you can monitor ICP actual, ICP desired and IPR duty cycle. You can also pull the ICP sensor and hook shop air to it. Hook a 12V external source up to the IPR (need a spare pigtail for this) and close it with the 12V's, apply the shop air and listen for leaks. Find the leak that way.

Definitely not a glow plug issue. Though that is odd that you keep getting all of these not communicating issues.... hmmm.

 

What is the normal to start one cold, I did not think 3 to 4 secs was that bad. It does not have time to warm up just start and kill it and it won't start again till it sits for a while. I have done the scanner thing, with an AE ford enhanced.
I'll try anything to get this thing going.
When I took it to get the pcm and ficm flashed they were the ones that could not get them flashed and replaced them to get it to start cold. When you start it and do not kill it, it will run over and hour with out stalling.

 

You did the AE scanner thing... what did you look for? What were the ICP readings?

Replacing a PCM and FICM seems like a complete waste, why wouldn't they be able to program them?? That was a Ford dealer that "couldn't program" them?

 

Yes everything scanned out ok except for the unable to communcate with the ficm.
It was an ex ford dealer with the ford scanner. Nothing showed up on his and the only way to get it to link was change both. Changed the ficm first and then had to change the pcm. Now get no codes but still starts good cold but no start after once started.
Lpop checked out good, now am checking the pipes, they were supposed to have been replaced with some that could not leak, but going to check them any way.

 

Which pipes are you referring to?

This is really weird. So even if the engine is ice cold, you fire it up and let it run for say... 60 seconds, shut it down, and go to restart, it wont fire up? How long do you have to wait for it to get going again?

 

Probably 30 minutes before it will start and does not turn much before it starts.
The pipes that feed the rails on top of the heads. Talked to a mech yesterday and said they sometime leak.
He also suggested that I change the crank pick up sensor. He said that sometime they get demagnatized and do not work as well as they should.

 

I wouldn't touch the crank or camshaft position sensors just yet, they often get replaced without warrant and don't usually fix issues. Not saying it's not the issue, but we need to verify it is before replacement.

I find it very odd that it will start without issue, then shut it down and it wont start, even if it's not fully warmed up, that's odd.

I'd like to know if it still has FICM SYNC when it's trying to restart. This is an odd problem.

 

Sorry haven't gotten back to you.
On first start the icp actual and desired stays close to the same. But when I turn it off and try to restart it the actual is anywhere from 100 psi up to 600 psi. If it sits just a little they will again be the same. The actual does not ever be the same until it sits a few minutes.
When I replaced the stand pipes the one on the drivers side the line that goes from the pipe to the rail can be moved up and down just a little. The other one is tight after it is snapped on and will not move. Could this be my problem?

Will the voltage on the icp reg cause it to do this, the voltage goes from over 1 volt down to .74.

 

The voltage is just telling you what the sensor is doing. Most guys with tuners use the voltage to know what the ICP is doing, since the pressure readings can be off. (written in the tune this way to fool the PCM into adding more ICP).

Next time it has this issue and wont start, unplug the ICP sensor and try starting, see if that changes anything.

Could just be a high pressure oil leak and your loose rail very well may be the culprit. Bob would know more about this, he's way more familiar with the pre-05 high pressure systems than I am.