Cm2350 high commanded vgt

[Rawze]

(11-14-2020 )Carhauler Wrote:  Ok, so I have logged the vgt and egr and various other parameters while driving, seems driving is fairly normal. Only idle is where is commands 80-90%. When egr starts to open it commands the highest and you can here the turbo whistle less from the drop in exhaust pressure.
There are no leaks in the egr system and the sensors and valve appear ok.

Did a regen last night. Dpf differential pressure ended up at .03 at idle. Didn’t take long either.

It has been pretty cold. 20-30 at night and 30-40 during the day.
When the Scr stays warm it seems to back off the vgt. Then it cools down and the cycle starts over.
Any ideas?

egr cooler partially clogged is most likely culprit at this point ... and that aftergarbage CAC.

[Carhauler]

Told the boss. He’s willing to have the mechanic replace the egr cooler with a Cummins one.
Going to clean the egr valve, also he said f it we’ll replace all the sensors on the cans so you don’t have anymore issues

[Carhauler]

Ok so little update... still haven’t replaced the egr cooler. Left the truck 3 times and our mechanic didn’t do it even though I got a egr cooler kit. I did replace the HP fuel pump head as a check valve failed. Truck also seems to have leaky injector(s), rail psi bleeds immediately on shutdown. I retorqued the fuel lines and tubes to no change.
Truck is also burning a TON of fuel if having to idle overnight. Like a noticeable amount on the gauge. Will also be able to manual regen in the morning from the switch. Turbo is also starting to hang up randomly. What a money pit. If it was mine it would be converted to ahem “less hassle”, but I guess that isn’t a option since I go to California regularly.
Lots of issues. Still runs fairly well. But with just shy of 600k miles go figure.

[tree98]

Sounds like it's been neglected it's whole life.

[Rawze]

(02-05-2021 )Carhauler Wrote:  Ok so little update... still haven’t replaced the egr cooler. Left the truck 3 times and our mechanic didn’t do it even though I got a egr cooler kit. I did replace the HP fuel pump head as a check valve failed. Truck also seems to have leaky injector(s), rail psi bleeds immediately on shutdown. I retorqued the fuel lines and tubes to no change.
Truck is also burning a TON of fuel if having to idle overnight. Like a noticeable amount on the gauge. Will also be able to manual regen in the morning from the switch. Turbo is also starting to hang up randomly. What a money pit. If it was mine it would be converted to ahem “less hassle”, but I guess that isn’t a option since I go to California regularly.
Lots of issues. Still runs fairly well. But with just shy of 600k miles go figure.

just an fyi: not encouraging it, but if the de-mandate you talk about is done correctly, the thing would pass those Cali inspections and sniff tests. There are plenty of of ppl here that visit the communist state and even have stickers where they get tested and all that stuff is hollow. Alternatively, the thing can be made much more lenient without removing anything via some custom programming to make it a lot less of a sensitive headache even if someone did want to leave it all in tack.

Like tree98 said...

Everything your describe screams a lifetime of neglect and also highly likely the thing has been driven its whole life mostly below 1500 rpm (considered abuse) . - Sad indeed. Cannot blame the engine on that but instead a lack of education towards proper care and maintenance. Repair shops any more will not help you actually "maintain" a truck these days, nor will they do anything preventative. Our industry has changed into this deranged mentality of "Drive it till it breaks, put out the fire using the least amount of effort, rinse and repeat." That and this stupid narrative used by the mega-fleets of jacking up rear axle ratios, starving the engine of useful power, resulting in increasing fuel mileage (due to starving the engine of actual power and excessive lugging) thru false means, lugging a diesel engine to death, cutting its lifespan severely.

... all the while, everyone wondering why they have noting but repeating and major problems as soon as the truck gets a bit of age on it. It becomes completely left to the truck owner and/or driver for avoiding all that stuff and therefore 85% of why O/O's and small fleets chase their tails, fighting all the problems and premature engine failures more than they make decent money. That or they resort to perpetually leasing newer equipment where a huge chunk of profits do noting but make truck payments to already rich, greedy OE dealers$its.


600k miles on a lugged to death + neglected engine = an engine at the end of its life already.

[JimT]

(02-05-2021 )Carhauler Wrote:  Ok so little update... still haven’t replaced the egr cooler. Left the truck 3 times and our mechanic didn’t do it even though I got a egr cooler kit. I did replace the HP fuel pump head as a check valve failed. Truck also seems to have leaky injector(s), rail psi bleeds immediately on shutdown. I retorqued the fuel lines and tubes to no change.
Truck is also burning a TON of fuel if having to idle overnight. Like a noticeable amount on the gauge. Will also be able to manual regen in the morning from the switch. Turbo is also starting to hang up randomly. What a money pit. If it was mine it would be converted to ahem “less hassle”, but I guess that isn’t a option since I go to California regularly.
Lots of issues. Still runs fairly well. But with just shy of 600k miles go figure.

What about the aftermarket CAC? Also, did anyone ever look at the SCR temp sensor? You mentioned it seemed like it was going into SCR warmup. Makes me think SCR temp sensor or EGR valve. Or the turbo failure is a result of the aftermarket CAC or maybe what you've been seeing/hearing from the turbo had been early signs of impending failure? I'd lean toward CAC being the cause, but that's my opinion.

As for the rail pressure loss there's also the rail pressure relief valve that could be the culprit. In addition to, or independent of, potential injector issues. Have you tried running injector performance tests and/or cylinder cutout tests from insite to look for abnormalities?

As for fuel usage, other then higher consumption due to things you mentioned, have you looked under the truck for fuel leaks? I know some trucks have been known to develop fuel leaks from lines in non-obvious places, such as above the DPF or exhaust elbows, where the fuel never makes it to the ground. I know on my own truck I found a spot where a fuel line had been rubbing on the frame. Not sure if it was actually leaking at the time, but it's location would have hid a small leak from being noticed.

Nothing you've mentioned makes me think that this truck is a unique money pit. It's just a heavy duty piece of equipment with complicated and sensitive systems (think aftertreatment) that hasn't been maintained to the level it requires. You may have done a lot of good preventative maintenance, but ultimately decisions and work beyond your ability have contributed to the present situation.

[Carhauler]

(02-05-2021 )tree98 Wrote:  Sounds like it's been neglected it's whole life.

Before we bought it and I started maintaining it, it wasn’t cared for at all. Used hard in local stop and go. Was a owner op truck. Guy ran it balls to the wall..... been fixing lots of things from lack of maintenance.

[Carhauler]

(02-05-2021 )Rawze Wrote:  ...
Like tree98 said...

Everything your describe screams a lifetime of neglect and also highly likely the thing has been driven its whole life mostly below 1500 rpm (considered abuse) . - Sad indeed....

We bought it at 350k and I have been the driver since purchase. I religiously follow your advice. Egr tune up when we got it, except egr cooler. Oil changes at 10-12k. New doc and dpf. I’m really ocd and picky.
When I get back to the shop I’m personally changing the egr cooler and turbo. Probably get some rail caps and start testing injectors.
I can basically spend and do as I need. Wish we had freight to Georgia.... not giving up on it yet. Still a nice truck.

[Carhauler]

Everything you mentioned has been done personally by me. On insight it passes everything.
I’m going to change the turbo and egr cooler when I get back up north.
It did this before the cac was changed.