Update:

We put a scanner on the truck today and the IPR duty cycle never went above 25-30%. We talked to a Ford tech (I don't know how 6.0 savvy he way) who thinks its an injector. He thinks the injector gets stuck open and allows air from compression into the fuel system. This would explain why my original post how that air was getting into the fuel bowl.

Do you think this is a possibility? If so, is there a way to identify which injector it is (other than with a scanner)?

 

If an injector was stuck open it would hydro lock the motor in short order (50 psi of fuel pouring into the cylinder).If you were getting air in the fuel it would be a leaky injector sleeve or crush ring. Also while it was running with an injector stuck open the truck would smoke up the block in a minute with unburnt fuel.

 

I was suspicious of an injector diagnosis because of the lack of an SES light or codes or smoke, but my bro-in-law was convinced the Ford Tech was on to something.

Without a doubt, a stuck-open injector would create black smoke, correct? Would it also set a SES light?

 

White stinky smoke and lots of it.At 3000 psi in the hp oil system IPR should be 30%.At Idle about 13% and max 86%.

 

Its too bad you are so far away. You would be buying the beer tonight.LOL

 

I'd love to buy you a case of Molsons, or whatever your flavor is! I'm a Fat Tire / Sammie Adams guy myself.

We did a buzz test on the injectors and everything came back normal. However, we still haven't done the cylinder balance test. Hope to figure out how to do that tomorrow.

The smoke we're getting is almost clear, so it's hard to determine how much of it there really is. However, its extremely raunchy. It stinks up the whole shop quickly and it lingers for hours even with the exhaust fans on.

Tomorrow we're also going to put a heat gun on each cylinder and see if that doesn't identify any oddities.

 

Its not hard to pull an injector. When the valve cover is off you will see a allen screw in the HPO rail thats the spot to plug in shop air. Good luck with it and have fun.

 

Somebody else pointed out this little gem of a test. Might give this a go too. Then we should have the both injectors and HPO leaks covered.

Balloon Test

 

Found cylinder imbalance codes on 2 and 6 this morning (second cylinder from the front on both sides). Still need to do the balloon test to confirm the injector diagnosis.

 

Wrong regarding locations of cylinders 2 and 6. I've learned they're both on the left bank, which is good news.

Is that the allen screw I see in the middle of the HPO rail in this photo?

 

Thats the one. Don't drop it

 

I stand corrected about an injector letting combustion gas pass through the injector it's self into the fuel rail.Diesel Technician Society

 

Yes sir. That's the site that describes the "Balloon Test" I linked to in post #23.

 

A little more warning regarding removal of that setscrew in the HPO rail would have been nice. However, I lucked out. When the smoke cleared (i.e. I wiped the oil off my glasses so I could see), the little setscrew landed right on top of the oil rail about two inches from the hole. I had NO CLUE where that thing went after it popped loose. Hilarious, thinking back about it. However, I was extremely lucky that I was able to find it.

When I put shop air (>150psi) to the HPO system, it was quiet as a mouse. I heard no leaks whatsoever.

Got the balloon test done and #6 appeared to be the culprit. I wish I had used water balloons so they would have fit tighter around the fuel line. With the zip ties pulled as tight as I could get them, the balloon stayed limp on all cylinders, except on #6 it filled so that it wasn't limp anymore. Not an obvious leak, but a leak none the less. I have an injector on the way.

 

Replaced #6 injector today. Running like a top again.

Learned a lot, including balloon test is easier than testing the HPO system for leaks so start there next time.

Thanks for everyone's help!