Hi All,

So awhile back this truck got STC, stand pipes, and dummy plugs done. I think that is when the miss started but it only happens under certain conditions, first oil has to be up to temp, it doesn't have the miss when the oil is cold. The most noticeable condition that causes a severe miss is revving the engine in park, it also misses while driving mostly after you've been on the throttle and then you let off and some other random situations but again only when the oil is hot. The FICM voltage was dipping down to 46 volts occasionally so we replaced the FICM and that didn't change the miss at all. It seems to be a high pressure oil problem to me based on the oil temp condition and also because it most likely starting to occur after HPOS repairs. I suspect it is an oring/nipple cup issue on the passenger side oil rail since we pulled it off to do the stand pipe on that side. The truck is an 05, below is a video showing an uncompensated power balance test but I don't know how to interpret it. Anyone have any thoughts on how we should proceed to fix the truck. I have IDS so we can run more tests etc if needed. Thanks!
https://youtu.be/rk337u_DcWQ

 

Do you have high idle?
Start the high idle and then clean the screen and then see what the trace does.
Th RPM bar needs to be blue to get a stable reading.

Here is one of Ron's videos on Youtube

You might take a look at the other videos he has up. I think he has more than
a few that he uses IDS to show. I think he also tells you what to look for.



Sean <BR>

6.0L Tech Folder

 

Did you inspect the upper seals on the injectors when the rail was off?
Air tested after stuff was back together?

 

I will get a new IDS reading in the next few days, unfortunately I am out of town right now. I will post up a new video once I have it.

 

Unfortunately we didn't inspect the injector seals when it was off. We don't have the fittings for an air test and if I remember correctly I thought you couldn't air test properly with updated standpipes because of the check valves or something. Is that not the case?

 

You can still air test. That check valve only slows the air flow down
when you put air pressure to the system. It it's hot then the oil will
move out faster and you may find the issue with it hot. It can make
a difference. I would get it hot before doing any air test in this case.

On the IDS go to the data logging and log the ICP,IPR and load.
Also you may want to look at the misfire count. When you in the data
logging you can do active command. You might try bumping the ICP
pressure up.

Here is a youtube on Active Command

You will need to do a little snooping but it's there and I have used it.



Sean <BR>

6.0L Tech Folder

 

Here is a link for the power balance test at high idle. Cylinder 3 looks a little out of wack and since it is on the passenger side that is the oil rail we took off which would make sense.

 

That one does look to be dragging the overall trace down.

Depending on how you feel about extra work you can move the injector
to a new hole and retest or just replace it if the top seal is looking chewed.



Sean <BR>

6.0L Tech Folder

 

So I think I want to air test the truck to make sure we get it right. So basically I just need to remove valve covers, buy the adapter that screws in where the ICP goes (05 so it should be right on top if I remember right), then use IDS to command the IPR closed and then apply as much air pressure as I can get (200 PSI), listen for leaks. Anything I am missing?

 

You might try first with the covers on. Saves work if you find that you can hear
the hiss from the Crank case vent or the oil fill tube. Also I think 125 PSI would
be a safe place to start. Compressed air can be very unfriendly at times.

Also cycle the key once before starting the process so that the spool
valves close after the buzz.


Sean


6.0L Tech Folder

 

So I was about to do the air test but I was searching about the internet and found TSB 08-18-6 which has to do with ICP pressure and one of the conditions is " If the engine starts with EOT at 195 degrees perform a run up test by a slow neutral run up in park/neutral. Does the engine run rough between 3000 and 4000 RPM?" If the answer is yes the first step they list is the replace the IPR. I remember when we took the IPR out previously the connector seemed a little loose. Do you think it is worth replacing the IPR first since I sort or remember something seemed weird about the connector and the fact that it is the first step in that TSB or should we move on to the air test?

 

The air test won't cost any $ where the IPR will unless you have one sitting around
to use as a test. Also when dealing with a mystery pressure issue you may want the
engine up to temp. The hot oil will leak better and the same can be said about the seals.



Sean


6.0L Tech Folder

 

I just wanted to report back how we fixed the truck in case anyone find this thread looking for help. We ended up replacing all injector o rings and nipple cups and o rings as well as the stand pipes and dummy plugs. All of the o rings and nipples cups looked fine so I think it was the stand pipes and dummy plugs that fixed it. Both dummy plugs looked fine but the stand pipes both came apart trying to get them out, I don't know what was wrong with the stand pipes but I suspect that was the issue and that one was defective to begin with because they were less than a year old.

 

Were the nipple cups loose. Could you wiggle them?

 

You could move them but there was resistance moving them. I wouldn't call it loose.