Question on smoke output

[Rawze]

(11-04-2016 )joed2323 Wrote:  Cm2250, 2012,
Truck has repeated frequent Regen issues, been on going for awhile

So looking at the codes,
first thing I did was remove the lower exhaust pipe below the doc, and the intercooler intake pipe from turbo fired truck up at a idle, and nothing but a oily/wet smoke shot out the exhaust piping/doc, it smoked up the whole garage.... I could wipe my fingers in the oily crap it spit out, or puked out warming up...

I didn't smell any diesel fuel, it didn't burn the eyes, but lots of black smoke shot out the exhaust pipe.

5 mins or so I bolted the piping back together and ran a few tests.

First one was, the fuel pressure test. The truck failed it miserably, it dropped like a rock from 29,989 to easily under 20,000 in like 15secs... Numerous times.

Did the one cyl cutout test, and all injectors sounded decent, motor didn't die out.

I replaced the fuel rail check valve. And it held fuel pressure after replacing the check valve.

My question is, once the motor warmed up, that black smoke quit blowing out the exhaust, but at a snap of throttle it still blew black smoke out (not as bad) where could all that black smoke be coming from??? Obviously this is contributing to all the excessive frequent regen codes..

The turbo is orginal, but the turbine wheel has play, im thinking it could be coming from the turbo or leaky valve guide seals, once motor warms up it doesnt piss oil out? Oil consumption isnt overly obsessive

Once the motor warmed up it quit smoking like a whor@
But have has repeated issues with this truck, I assumed at first it was a injector issue and over fueling or dumpin fuel but I had the exhaust pipe back off after the motor warmed up and it seemed like she quit pissin black smoke/wet moisture

Literally when I first fired up the truck with that bottom doc exhaust pipe off, It spit out a huge gulp black sooty oil/watery mixture... I had my head near it and it did not burn my eyes so my assumption of over fueling was wrong at first with the drop of fuel rail pressure at start...

Replaced that check valve and it fixed the drop of fuel rail pressure. It still doesnt explain the "high smoke output"

* The turbo is supposed to have up to 0.045" side-play in the turbine, and you can definitely feel it, so it is likely normal. I would not be so quick to blame the turbo without pulling the actuator off and giving it an inspection, but it has to be re-calibrated properly as you re-install it (I.E. don't pull it off unless you have Insite handy and can re-calibrate it). That is what OEM shops do. they are quick to blame a turbo and waste your money in the process.


Have you done an EGR tune-up on it throughly? and replaced all the sensors? -- It sounds like it is getting too much EGR into the intake because a sensor is reading wrong or the EGR valve is not operating correctly.

MAKE SURE you don't have an after-market EGR cooler or CAC unit on it like Duralite, etc... They are notorious for being problematic and restrictive and causing excess soot problems, and air flow restrictions.

The CM2250's are notorious for over-boosting and also making a bit of black smoke from the factory when you romp on the accelerator, especially when they are warming up. The DOC/DPF keep it from comming out the exhaust and most of all the soot goes right into the EGR and into the oil pan, slowly destroying the engine. it is quite normal, so If you don't plan on installing MM-2 in it,.. get a bypass filter on that thing ASAP while your at it.!

The wet watery substance,.. unless your loosing coolant (or it smalls like coolant) is likely just condensation. They put out a LOT of condensation when they crank up if they are not warmed up yet. It is an engine. -- And YES,... This contributes towards clogging up the DPF can over time. Combine that and someone romping the fuel pedal (or driving it before it is warmed up) and you got a recipe for DPF problems all the time there for sure.

The CM2250's are notorious for the valve guide seals leaking and needing replacing. That is what you should be looking at if the exhaust has oil in it,.. this will KILL the DOC/DPF can and keep them clogged up all the time/face plug them repeatedly. The turbo and exhaust manifold needs to be pulled off and and the exhaust valves inspect for wet oil on the stems. If your getting oil in the exhaust. The turbo needs to be inspected for this problem too, but it can also be soot-packed and worn out rings that have caused excess liner wear in the cylinders too.

REPLACE the IMAP and Exhaust BP sensors if they are more than 100k miles old.

CKECK the engine for boost and exhaust leaks and pressure test the engine to ensure the CAC, Intake, EGR, etc. on the engine for air and exhaust are not leaky.

Pressurize the coolant system and let it sit overnight and check for external leaks,.. and also check the back side of the EGR cooler to see if it is getting wet with coolant as well by removing the pipe on the back side of it and looking inside it with a mirror and flashlight.

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And as well, if your going to keep the emissions system on it and running...

I suggest -- DO A THOROUGH EGR TUNE-UP. Check the entire EGR system and clean it out thoroughly and replace old sensors. Replace the Delta-P sensor and clean its feed ports out too. Clean out and make sure the EGR valve is in good operation. A clean healthy engine needs clean healthy EGR components and clean, non-restrictive piping to work properly.

GET A BYPASS FILTER ON THE OIL SYSTEM ASAP and keep that soot out of the oil and eating up your engine!. ALL these newer egr engines are NOTORIOUS for carbon and soot packing via the oil and destroying the liners and piston rings prematurely. if ANYONE wants their engine to last more than 400k miles and not have excessive engine wear, atc... The engine needs something to keep the soot out of it. It is a very serious issue and everyone seems to take it for granted then complain when everything is worn out prematurely.

Ensure the NOX sensors are not too old. The one on the back side of the turbo likes to reads incorrectly after 200k miles or so and cause the EGR to be too high into the intake, making for excess black smoke long before they give and kind of fault. The ones mounted on the emissions system make it use too much DEF fluid, and also cause other problems.