Stumbling after injector o-ring replacement

[itsme]

I have a 2000 7.3 and it suddenly wouldn't start. The oil was suddenly 2 quarts low and I never have to add any between changes but check it all the time. The tach was jumping so I figured it wasn't the CPS and with the low oil decided to replace the injector o-rings since I knew I had 2 bad glow plugs and was going to go ahead and do them all so might as well do the o-rings while in there. Once I finished that, it still wouldn't start and nothing from the tach. Put in a CPS, and after some cranking, it started. It's now taking longer to start where it used to be pretty immediate. A puff of white smoke when it starts. It idles fine. Took it for a test drive and it was stumbling, stuttering or whatever pretty badly. Like's it's running normally for a few seconds then hesitates, then back to normal. After a 1/4 mile of this it starts pouring white smoke out. I stop and the smoke stops and I limp back home even slower.

I've read where the truck may not run normal until all the air is out of the system but I can't drive it anywhere like this. I also read that white smoke can mean a loose injector. They all went back in smooth enough. I can pull them and check the o-rings and re-install them. I don't have a code reader. Are there any other tests to determine if that is the issue and which one it is? Thanks.

[itsme]

I pulled the injectors again, checked the orings (fine), put the injectors back in. Same issue. Tried another CPS, no help. Got Autoenginuity. The only code it's reporting is P0476. I'm going to clean the tube tomorrow to see if I can get rid of that code. Passes buzz test and cylinder contribution tests. Also put in new fuel filter. The stumbling, bucking thing starts at around 1500 RPMs. Any ideas on what to try next?

[kblv247]

i am having pretty much the same symptoms, i replaced orings and the truck started right away but seemed like it was missing on one. so i shut it off for about 10 minutes. on the restart it seemed like it was only running on four and was really running ruff. i checked the hpop reservoir and it was full. checked for codes and had none. it starts up and when i rev it it acts like it starving for fuel or oil and eventually dies.

[kblv247]

this worked for me:
Yes. You didn't get one of the injectors seated all the way and now compression is bleeding back into the fuel rail. It's causing a whole side to not get fuel which is why it feels like it's only running on 4 injectors.


Go under the truck and disconnect the fuel pump wiring. Then pull both the small fuel lines going to the heads off from the fuel filter housing. Crank the engine and one of the lines should start pumping pressure off. Trace the line to whichever head and this is the side that the injector is messed up on. You will then have to pull all the injectors to figure out which one it is. You will probably be fine with just replacing the orings on that one injector.

[itsme]

I forgot to update this after the problem was resolved. In my case it was a bad CPS. The original CPS was bad and I replaced it with one from O'Reilly. I tried a second one from there (after reading that they are prone to issues even when new) and the symptoms were the same. After verifying everything else multiple times, I got one from Ford. That took care of the problem. And I was able to return both of the O'Reilly ones after explaining the issue to them.