Cm2350 high commanded vgt

[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.