i came across an issue with my 2006 6.0 and it has me stumpped. The truck fires right up in the morning and runs great. once it gets warmed up and you shut it off, it doesn't want to start back up. let it sit for an hour and it will fire right up. i hooked my laptop to it and when its hot the desired icp pressure to start is 4000 to 6000 kpa the truck cranking is making 2600to 2800kpa i am under the thought that we only need 800kpa to start the truck

 

800 kPa is only 116 psi. You need 500 psi to start the 6.0L.

Also, you need to watch the ICP sensor volts "PID" to know what the real pressure is because the PCM sometimes "assumes" an ICP pressure if it doesn't like the actual ICP sensor voltage. It does that to help the engine start if the ICP sensor is bad.

 

So you own a diesel shop?