Backround: 2006 f350. New head gaskets and bolts. new oil cooler and egr cooler. 5 reman injectors. all new injector o-rings. new stand pipes and spt fitting. New fuel and oil filters. Original issue was I had 3 bad injectors and 2 sounded weak on the buzz test. So I replaced 5 (all i could afford with all the other parts) after replacing injectors truck ran like poo still, checked numbers and my oil was hotter than coolant by 30ish degrees. So, I went ahead and did all the other stuff listed above thinking maybe I had low HPOP pressure. SO.... all back together and now injector 7 is causing a failed bubble test. Replaced orings again and injector hold down is tight. Blew oil out of holes before reinstalling. Dont know what to do next. Thought if injector cup was bad i would get fuel in coolant. Please help, need truck fixed ASAP. Thank you

 

Blowing the holes out is good, but define tight. Did you use a torque wrench? IIRC they should be torqued to 24 ft lbs.

 

Replace the #7 hold down. You mention orings,, but did you replace the copper crush washer at the nozzle?

 

You thinking stacked copper washers?



Sean

6.0L Tech Folder

 

Okay, so I initially torqued them to 24ft lbs, then read online that ford bumped it to 26ft lbs, so i did that. Still getting bubbles. Then I read online that builders are doing 28ft lbs, so i did that, still getting bubbles. I used a torque wrench that gets calibrated every 6months. For the copper washer, yes I replaced it and no I did not double stack it. I am going to try the hold down, i just found a dealership that has one. I will keep you guys posted, probably wont get it in until tomorrow after work. Thank you thus far though.

 

I would suspect stacked washers as well. You may need to clean the washer hole as well.

 

What kind of injectors did you buy... Ford remans, or cheapos? My injectors failed a bubble test after new o-rings and washers, so I took them to my revered diesel shop, they tested them, and said they were leaking out of the body. I had fuel in my oil from them leaking. They were cheapos, the tech told me to replace them all. Not sure where they would leak, I don't know much about the injectors themselves.
And the shop also told me to torque to 28lbs. And the bubbles quit when I changed them.

 

Adam, if I'm reading your post correctly, #7 injector has NOT been replaced but only resealed & torqued? If so and it is still failing bubble test, it's more than likely a bad injector that the pintle inside is not seating allowing compression chamber gases into the fuel system. I've had this happen and I'll try to post a video I made.
For a test, pull the injector and put a rubber hose on the injector tip. Next, pressurize the hose with shop air. While pressurized, cover the fuel inlet screens on the injector body and see if there is air pressure building and signs of bubbles. If air is escaping, replace injector.

Hope this is all clear. I'll try to get the video up. Here's a pic for now.

 

Thanks for posting that. An interesting test that I may have to do. Did you see any fuel pressure issues with that injector installed? Any variation with the IDS comparison?

 

Sounds like a bad injector on 7. Being that it is number 7 which failed, I suggest you check fuel pressure while driving. Min 45 psi. low fuel pressure will kill injectors in notime.

 

Didn't have to use the IDS. Fuel pressure was fine. The truck ran fine @ higher rpm. It was @ idle after 20 seconds or so it would start missing because it was filling the fuel rail with air and knocking off the other 2 adjacent cylinders. I narrowed it down to what side then cranked it with a glow plug removed one at a time until the bubbles stopped. With the glow plug removed and no more bubbles tells you that's the offending cylinder. After that I pull the injector, inspect crush washer and orings, then do the test above proving it's the injector pintle.

 

Excellent info 87crewdually. That's probably what was happening with mine... amongst other things.

 

This is the curious fuel pressure variation I'm seeing. The pressure is steady during initial hfcm run before the engine starts but once it's started there is this rymthic condition. This video is short but the gauge just keeps repeating the same sweeps. Individual injector shutdown has no effect and no sign of bubbles in the fuel bowl when just engaging the starter.

 

I just had same issue after a lot of the same work. I replaced four remanned injectors and after a lot of problem solving we came to one of the injectors being the issue. I called the company and they air mailed four replacements and that took care of the problem. Also check your fuel supply line o-rings and replace them.

 

If it was an injector I'd expect it to pulse up in pressure, not down. That appears to be a small sudden loss, like the regulator valve is opening suddenly and then closing again. You could pull one glow plug at a time to see when/if it stops.
My gauge will fluctuate like that too, mostly at high idle. No worries here. Runs great with no issues.