I am unsure on this. I have some situations where the difference is obvious, and others where I can't spot it.

 

What about sides, is it usually the hotter side or the cooler one?

 

If it's cooler, it's likely an injector problem. Unfortunately, a broken tip can cause the EGTs to really hop... so looking for a thermal prairie dog would be on the opposite side of his brother - the mole.

Does the truck feel like it has a slight miss? Was there white smoke at start-up last winter? Does black smoke occur without getting on it? Is the exhaust surprisingly cleaner from what you expected?

 

Wonderful. I guess I can play the odds. What are the odds of a broken tip vs a bad injector?

Not all the time. But when it feels particularly doggy it seems like there could be a slight miss. Something seems a little off... Sorry I know it's a vague answer.


Yes some on cold days. Isn't that normal?


No, as a matter of fact I can't seem to do anything to get black smoke. I tried a 4/3 WOT downshift on a hill as well as 0-65 WOT with someone looking for smoke in the side mirror and they reported nothing.


Also, my fuel filter has been black for a while [ https://www.ford-trucks.com/forums/1...el-filter.html ]. I left the the stuff I drained in a jar for months looking for oil to separate out and got nothing....





See above, it seems cleaner than it should be.

In the distant past, I recall having to clean soot off the rear corner panel but I haven't had to do that in a while.

 

I'm beginning to think this is not a boost problem, but a fuel delivery problem - total reboot on our thinking. I take some blame on this one. Someone saying "low boost" doesn't necessarily mean all gears mesh toward solving an air problem. Low boost also stems from no real power going on. Unfortunately, the OBDII data doesn't always show this unless you're looking closely for a fueling problem. The ICP and FIPW can be there, but that doesn't mean all 8 injectors are doing what they're told. You can have one holdout, dropping your boost - and I'd bet giving a bouncy EBP (rapid unfire "dud-dud-dud-dud").

Black fuel filter? Uh... er... injector O-rings - but IPR should show that if we look closely.

 

There are some fuel filter photos in the link above. I don't think it's oil, since there's none in the drained out fuel. But I don't think it's algae either - isn't water needed for that? I never get water when I drain the fuel filter....

Here's some PERDLs and IPR data:

 

With that data, your ICP is not exactly where I'd want to see it with the IPR you show. I'm starting to suspect injector O-rings or a bleeding stick in a big way. What's your idle IPR?

 

Watching and learning...carry on, gentlemen

 

At Idle

IPR is 11.72
Pulse Width 2.66-2.88
ICP 466-497

 

Bleeding to where? Would this show fuel in an oil analysis?

 

This would show oil in fuel - the oil has a much higher pressure than the fuel on the opposite side of an injector O-ring. Cody test is in order.

 

I found this:

So, if all seems well except at higher loads and I need to add about 1 QT of oil after 3500 miles then if it is the injector o-rings it's probably a small leak. Is that a reasonable assumption?

If it's a small leak should I be doing more of a leak down test where I pressurize the rail and see if it holds 80-100 PSI for some time (an hour)?

 

That would be reasonable.

 

Set of 8 injector orings from Alliant:

But DON'T trust the pricing. Amazon plays "price ramping" games. Since I ordered once, when I go back to that item with my account it will ALWAYS be higher priced

Not sure that is legal (or not), but I've successfully defeated it in the past by logging out, blocking cookies, and searching for the exact same item, then logging back in at checkout.

There may be a Truth in Advertising or Truth in Pricing thing there, but I'm no expert. Just know it and buyer beware of their scheme

It does take a fairly complete teardown to change them. And be prepared to take extra time to deal with whatever else you find.

My build thread in my sig gives a lot more details


Testing for leaks?

Here is what I've observed.

1. Start cold engine, count 1-Mississippi, 2-Miss...etc until it starts
2. Let it run about a minute or so
3. Shut off and wait about 30 secs, start and count again
4. Let it run about a minute or so
5. Shut off and wait about 2-3 mins, start and count again
6. Optionally, repeat with 10-15min interval

If you are seeing longer start times- more than about half a sec- you may be getting bleed down of oil pressure through the injectors.

Longer startup times can point to this also.

Mine went from "forever" to about 1.5-2secs on start...every time. Realistically, I think it was maybe 4 secs or so, but compared to a gasser it seemed like forever

Of course there are other things that could cause the above- fuel issues, HPOP itself, UVCH, etc. But it is something that can be indicative of *some* kind of problem, of which leaking injector o-rings is at the top (unless you are seeing oil or fuel pressure issues)

Hope this helps! Looks like you are getting things narrowed down

Just don't be afraid to jump in and spend "small" monies on high wear/high failure items in the meantime. I don't consider those a waste. Worst case, it goes to maintenance and longevity

 

Did my idle IPR reveal anything helpful?


Should injector O-Rings just be done as a matter of course for these trucks (~140K Miles)?

Rather than spend the time to build a leak down tester etc, should I just be putting that effort into replacing the O-Rings - being confident that even if it did not solve the problem that it's something that needs to get done anyway?