So recently traded out my blown 6.0l for a used one. Install went ok. Determined that the ficm was bad in the used motor when 4 injectors wouldn't work when we tried starting it. So replaced it got the codes to go away and got them working. Still truck won't start. In the scan tool it says that the ficm isn't in "sync" I'm.guessing that means to the main computer. Anyway not sure if that could b a problem or not for getting it to run. Other code I got was for a bad glow plug. Which should b ok in terms of getting it to start up. All my pressures amd pumps are fine and getting fuel . Not sure if there is still to much air n the lines perhaps mayb the issue. They're bubbles coming up thru fuel filter. Not sure how to exactly purge all the air from the system. But was thinking that it should atleast start and shut down at the very least even if there was air in there. Also while putting the new motor in we put the upgraded oil cooler in and egr delete. Wouldn't think these would have an impact on starting but what do I know. So if you guys have any thoughts on why or mayb would I could try or look for, to try and get this thing started I would appreciate all the input. Thank guys

 

So is it sucking air
or is it an Injector


did you change fuel filters


KOEO several times should purge air if system is sealed should go away

 

It can take quite a bit of cranking to get it to fire after oil cooler work, I would pull the IPR and make sure the screen isn't sucked in. What is the ICP getting up to while cranking?
Also air bubbles coming into the secondary filter housing while cranking isn't a good sign.

 

my bad never saw the oil cooler


so you have aerated fuel?


My last oil cooler I dumped 2qt down that standpipe and started almost immediately

 

If you don't have sync it will never start. Check cam, crank sensors. Specifically cam sensor plug and harness. C1275