Okay, so I tried something similar to this once before and didn't get much. I have a video this time so that's good!

Since my last post I've changed turbos, HPOP and ICP, and added a 6.0 intercooler. 344k.

I haven't driven the truck since July, but took it for a ~800 mile round trip and it did fine, except these two issues that have got to be related.

1. when flooring it off a light in 2nd gear, OR openly revving it, it stumbles right as it makes boost. Sputters for a bit and then clears up and boosts like normal.
2. When coasting downhill, engine braking, there is EXCESSIVE white/blue, and occasionally black smoke when re applying throttle (i know throttle isn't correct for a diesel idc). Sputters, almost like it's clearing whatever crap is out of the system, and then pulls like normal. Ambient temperature was ~10 degrees F.

Here's a video:
https://drive.google.com/file/d/1U7Y...ew?usp=sharing

This makes long descents terrible because I regularly have to mat it and clear it up just to continue down the road. No other issues for the rest of the trip though.

I guess it also helps to mention that the idle is a little shaky. It's been a while since I've done a datalog last but last time I datalogged (i believe it's even on this account somewhere in previous posts) it looked fine. I'll datalog again while recreating this issue just in case though.


Initially, issue 1 makes me believe fuel pressure. However, sticking it into 4th or 5th and matting it still pulls fine, and my fuel pump (I have a super duty electric system) keeps 60psi with the occasional dip to about 53 when it really boosts.

Issue 2 makes me think the combustion chamber is just too cold, and with the added intercooler, it's just making things worse. But this doesn't happen on 6.0s or other intercooled 7.3s "normally," so something isn't running right. Plus, that much smoke just seems excessive. If anyone disagrees, I have a very open mind so if you believe differently please let me know.

I would think this issue is more a possibility of a few things, or a combination of the following:
-leaky turbo, or PCV, is funneling oil into the intake and making the truck run off it. That's why it happens when RPMs are high and it takes a while to "clear" everything out.
-failing/sticky IPR valve. I've had suspicions about this, and I wonder if the free revving explains that--perhaps it just is not opening and able to move as fast as the engine is demanding it to.
-Oh god please don't be a valvetrain issue
-sticky fuel injector, dribbling fuel into combustion chamber after it's supposed to be off. (Wouldn't this make it fire on that cylinder, though? unless it hasn't achieved proper atomization?)

One thing I noticed too. The underside of the truck is covered in oil. I'll have to check to see how much I leaked out, I did a fresh oil change and overfilled a tad with 16 quarts and a bottle of stiction eliminator. Normally 16 quarts is fine so I'm a quart over, it seems. (truck is a 97)
This oil makes me wonder if my turbo is leaking or something, and I'll have to check my HPOP lines. damn kb diesel performance lines have done nothing but leak on me so I always have to go back and check.

Thoughts?

 

Could be bad injector/s or wiring problem in the UVCH or connectors.

Time to invest in Forscan and start monitoring the vitals.

 

I have forscan and have plenty of datalogging capability. I've put super duty UVCHs and redid the harness, and the injectors were put on october 2021.

if it were bad UVCH it would be MORE prone to doing it on rough surfaces and not only coasting. Additionally, I would ALSO notice stuttering and issues when constantly in it. I can tow a trailer at a 7% incline at 65mph with zero issues.

I'll do some datalogging on forscan and try to figure out what IPR is doing. Issue is the comms line doesn't have a high enough baudrate--I would think comms would have the same baudrate as the PCM's digital inputs but it might be slower. An oscilloscope would be ideal in this case. I'll report my findings when I get a chance to work on it though!