I have an early 2004 6.0 that I can't get to start. I bought the truck as a project and dont know much about it. The previous owner said it needed 2 injectors and a ICP sensor which he had started to replace the sensor but gave up.

After I replaced the ICP the truck still wouldnt start. So I bought auto enginuity and checked the engine to find that it had low high pressure oil psi. The ICP read .22v. A few months later the HPOP was finally replaced as well as the ficm from ficmrepair.com.

Now I've been trying to get it to start and its still not going. I did an injectors buzz test and it said 1,4,6,7 had low circuit. If I go try to start the truck after its been sitting it will knock like a 7.3 with a loose wiring harness or like its not getting enough fuel and it will puff out a good amount of black smoke for one attempt. After I let the starter cool it might keep knocking with no smoke or it might just crank. When it knocks with no smoke AE reads 2300psi for the ICP. When it just cranks AE reads 3200psi.

All fluids are topped off and recently replaced as well as new filters all around. I found what looked like chewed up metal injector o rings around the IPR valve and on the HPOP. But I have a hard time believing there are 4 bad injectors. And the truck does build base oil pressure.

It seems like maybe a wire somewhere is loose? Any ideas where to look/what to do?

 

Monitor ICP actual vs ICP desired as well as IPR duty cycle.

What's really odd about those injector numbers is that would signify a bad FICM, since I believe those 4 are run off one plug on the FICM. You may want to double check your connections on the FICM.

Have you tried verifying voltage on the FICM too? Test that with a multi-meter.

ICP shouldn't be that high when cranking it. I could see ICP desired creeping up that high if the IRP is plugged or something.

Just thinking about the previous history, the IPR probably needs to be replaced as well, I bet the screen is torn and it's stuck open.