Trying to figure out why it wont start. Cranks good just wont start. Hooked up my scanner and monitored icp pressure and the pump isnt building up enough pressure to actually fire the injectors. So I removed the valve covers to check for leaks at the manifold and there wasnt any leaks. So I know it needs a new pump just wondering if it needs a new ipr valve, or any other parts while im there help please.

 

IMO, If a new IPR valve is on the cheap, I'd replace it.

 

I would add air pressure to the system and see if commanding the IPR closed changed the sound of the air leaking out at the back of the engine.