Cummins ISM CM876 hard start ONLY when hot

I have a cummins ism in the shop and the complaint is a hard start when hot. i have only been able to duplicate the problem 4 times after running the engine for an hour, shutdown and it will crank for 10 to 15 seconds and fire up sometimes misfire a bit but usually run fine. the truck has brand new injectors and fuel pump. When issue is present and it won't start i have 150psi of fuel pressure out of the pump. Anyone ever come across this? I am going to try a test ECM tomorrow

 

i keep thinking must be a fuel issue must be a fuel issue but 150psi while cranking is plenty of pressure, when it won't start engine cranks at 350rpms. No faults. Seems to have some blow by which is something i need to measure, but again only happens when hot and not everytime

 

also engine has egr and vgt actuated turbo, both have been checked

 

nothing??

 

no faults and it has a brand new pump which has a new fuel shutoff solenoid on it, I have insite. just put a test ECM on it, keeping fingers crossed

 

theory is when ECM gets hot connections in the ECM expand

 

well that wasn't the problem haha, blow by is in spec as well