steeler

That was it. Strange that I didn't have any egr related codes, but that explains the climbing soot level. I really didn't know that egr diff pressure played that big of a role in calculating soot. Oh well thank you guys for the help as always!

Strikeout with the 7th injector. No change. But I noticed while the engine was running the egr mass flow serious occasionally jump. It didn't look right with the valve commanded at 0%. I got digging and found where somebody had spliced a new connector on the egr diff pressure sensor, I checked continuity to the ecu abs found they had 2 wires spliced backwards! I have high hopes that'll fix it.

Pm sensor they replaced at well. Pretty much everything has been replaced before it came to me. BUT I noticed last night they put the wrong 7th injector in it. Fingers crossed!

Turbo is new, they did that along with injectors and cam. Ahi has not been replaced, but it's opening and passing the test in tech tool like it should. For some reason the ecu just isn't telling it to start dosing during regen. Also I should add that the soot level will skyrocket during regen. If you call what is doing a regen... If I reset soot level, it'll go from 19% to 160 in about 30 minutes. No engine smoke, runs fine until it derate fire high soot. Filter has been pulled and replaced 3 times by customer during this diagnostic nightmare and it's clean. So, from what I'm seeing, it's not really sooting up, it just thinks it is. Dpf diff pressure looks good at.... . 12 during regen. I'm trying not to parts cannon. The customer has already launched a boat load at it with no luck lol.

7th injector is good. Swapped the acm with no change. Head scratcher!

Yeah that was my first thought. I reset everything with no luck. Swapped ecu with a different truck, still nothing. Getting ready to swap acm and try that!

2021 mp8. The truck came to us for not completing a regen. Using tech tool I start the regen but it never commands the hi to start dosing. Engine idles up, exhaust temps look good in the 550's and I can see the ahi module go thru it's checks.. Then it just sits there. Never starts dosing. Before it came to us it had new injectors, turbo, manifold, and the entire 1 box is new.. I'm getting, or maybe I already am.. Stumped!

I had a customer that had put new injectors in a epa 10 mp7, but somehow put epa 10 mp8 injectors in it. It came to me because it ran HORRIBLE! In my case the mp7 did not like mp8 injectors in it at all! I had no knowledge that they had even put new injectors in it. Chased that one for a couple days before I discovered the problem. So... They might not have been mp8 injectors, but they definitely could've been the wrong mp7 ones lol!

Agreed! That 600 is the delete kit, and the updated rail pressure sensor and rear injector harness. If the sensor and harness have already been updated, then probably way less than 600.

Yup, that's the difference between big city dealer vs mom and pop in Kentucky! 😂 At least they won't have you down for 2 weeks like some shops around here.

I guess it depends on his location. I assume big city dealerships are way more expensive than small city mom and pop shops.

Yeah I do a lot of these deletes. I'm not sure what the parts cost, but it's a really easy fix other than updating the software for the accessory kit. 3k sounds high! Edited to add... I had to check to see what we charge for the delete. About $1000. Dang maybe we are too cheap! Parts are less than 600 bucks, and the job only takes a couple hrs max.

A little late to the party but I was going to say it was the water pump. I've seen 2 so far that turned the coolant purple/black due to the fins rubbing. Surprisingly neither were leaking though. Glad you found the problem!

I ran across one like that, hollowed out, but not deleted.... Go figure lol

Same here. We have customers that run 80 90 without issues in them, but unless the customer requests otherwise, we fill all rebuilds with 50w synthetic.

Yours doesn't have a check engine light, just the lightning bolt and red shut down light. You can get the lightning bolt to blink any active codes for you by turning cruise off, then hold down (I think it's down?) the set/decel switch until the light starts blinking a 2 digit number...

You probably won't have much luck locking the range cylinder in by hand. It takes a decent amount of pressure. But if your problem isn't with the cylinder/stuck piston, then you'll be removing the auxiliary section anyway. Assuming it isn't an air pressure problem.

The larger piston is your range cylinder, smaller is reduction. In high range the large piston will be pushed towards the front of the transmission, to the rear for low. Like Joey said, you can remove that whole range housing by removing the air lines, 5 bolts and 2 nuts on the pistons. The shift forks will stay in the transmission and won't go anywhere. They make a kit with gaskets and o rings to service the housing.

Was there any gunk/rust in that deep reduction cylinder? I've seen many that are rusted up and not used often, then when they get used they stick and have your exact issue... I've built 100's of 8ll's. I could almost do one blindfolded lol. No joke

I think it was around 10k in Volvos pocket!

Just a final update. Almost a month later and no problems, so...... Aftermarket Dpf, was the culprit. For whatever reason, this truck did not like it and wanted the big $$ oem!

Probably coincidence. Couldn't tell you how many cam failures I've done and found an eup with the dangling spring. H ring/lifter failure had nothing to do with the eup coming apart imo.

Lol if it can happen, it'll happen to me! Had an mp today that would only run for 10 seconds then shut off, losing communication from engine ecu. Turned out it was a leaking freeze plug in the turbo, behind the vgt actuator. Coolant had leaked in between turbo and actuator, getting inside actuator and shorting out, causing the ecu to go dead. That was a first for me. As far as my original post, I don't want to jinx myself but 2 days in and so far the truck is doing fine. Fingers crossed that it just didn't like the aftermarket Dpf!

Yeah, going to release it to the customer and let them run it and see what we've got. I'll post the result in a few days!

Ok, went with oem filter, test drove same route as before. Probably 50 miles. Soot level with oem filter went from 5 to 31 after drive. With aftermarket filter I went from 0 soot to 77...... Big difference