What you guys think about this: Cummins M11, PT-vs fuel system, non STC - has about 7 psi of boost pressure at high idle, as soon it comes under load goes to 0! Lots of black smoke and soot everywhere! No power, starts beautifully! Injectors were checked and rebuild. Overhead service was NOT done after re installation, haven’t measured any fuel pressures yet, accessory drive bushing in front cover shot to hell!
Rebuilt injectors need to be adjusted? Turbo shot? Extra exhaust pressure pushing the turbine toward the cold side and stops rotation. Why were the injectors pulled and rebuilt? It sounds like the boost was gone before the injectors were pulled.
It’s in the excavator, regular complain about “bogging down the engine”, EPPRV wires were ripped out, I fixed them but problem remained. All the current and corresponding power shift pressures checked out. Owner sweared that’s engine was checked before, injectors been pulled and rebuilt. Well naturally I didn’t believe him, went out there today by myself and first thing I did is checked the boost pressure because that engine was smoking black upon start up and idle and high idle! i thought about turbine hitting the housing on too much axial clearance too, that turbo has no waste gate.
And as far as I see that machine was abused very much. But it’s first time in my experience I see boost drop to zero under load! I have a feeling that even after turbo problems will be resolved there will be more problems! Interesting that owner do not regard accessory drive bushing being shot as serious problem, although I told him several times!
Forgot to mention: either gear pump or pulsation dampener leaking fuel, about drop every two seconds. I never messed with PT fuel systems ( select, select plus only) but I don’t think it is good for engine torque. This one is truly “multiple offenders deluxe”!
If the injectors were not adjusted after installation?...I would do that first, otherwise you could end up chasing your tail! Regards, Bob
If they aren't trashed already.
It was late yesterday and I just stopped by to quickly check the boost pressure on my way from another job. This morning i stopped by and wiggled the turbine shaft - that thing has all kinds of huge slops, both radial and axial!!! It’s amazing how it’s not leaking oil! Called owner told him he needs new turbo , overhead service and take care of accessory drive URGENTLY!
Had a guy call me a few years ago and ask me if I could set the top end on his 290 after he replaced the head gaskets, I said "Sure let me know when you want me to come out". Three days later this old IH dump pulls into the yard billowing white smoke. That was the truck... Lucky for him nothing was too tight and punched an injector out. Ran the overhead and life was good with no more smoke.
Late to the party but axial play stops the turbo under load, as you know now. Boss has a friend with crushing biz, Komatsu 250, the one with the bucket issue, Had dealer come out to set pumps because of too much load on engine, 6BTA. Didnt fix it. Same boost issue, a turbo build solved it. This owner DOES NOT let things idle for a bit before shutdown. Cokes up the turbine heatshield, turbo stops turning. Does same thing on his volvos, BUT it keeps me in turbo work for him.LOL Now if we could get this bucket issue resolved.
Check charged air cooler for obstructions. Are the joint hoses collapsing? Is the cooler leaking or any pipes broken or rubbed through? As far as overhead, I would adjust all using OBC method. (Especially since they are STC) What kinda machine are you dealing with? Komatsu? STC valve uses a fuel S/O solenoid to control timing.
Hyundai R350-3, doesn’t have intercooler or wastegate. But engine has aftercooler, jacket with coolant around intake manifold! Non STC - straight mechanical.
I would still run the overhead using Outer base circle method. You get the consistency of the adjustment on the injectors 100% every time. I would still look at that charged air cooler and see if there's any restriction or garbage sitting on top of the heat exchanger in There. Is there any chance the air filters are washed paper cellulose. I want said a customer who thought he was saving a fortune by washing is filters. It turns out when the filter media got wet It would stop being filter media and turn to more evee paper that would actually black or restrict air flow. Perhaps maybe try running without the air filter just so that you could monitor to Turbo chargers in late and see if it is in fact stalling . Just a thought
And I almost forgot did you inspect the pulse damper diaphragm. If that little rascal gets cracked or sticks it causes all kinds of terrible behavior.
For the second time - no intercooler/charge air cooler, and yes - like I said above something leaking in vicinity of gear pump and pulsation dampener. The owner got all information from me what needs to be done, and I’m waiting for him to call me.