6.0 Injector control pressure

[blackandstacked]

I'm working on an early production 03. The truck had 6 injectors changed and was running good. Lost injector control pressure. No visible high pressure leaks under the valve covers. This is the engine with the log style oil rails. I have no means of comanding the IPR closed to check for leaks with air. Any suggestions. IPR maybe? It will only build 339 psi. If i am not mistaken the truck has also had an hpop installed.

 

[wewille]

Its gotta have at least 500 psi to start. What is your ipr% when cranking? If you backprobe the yellow wire with red tracer and ground it the ipr will be closed, so you can do your leak test. Also how long was it running after the injector replacement before you started having your problem????