Cummins ISX CM871 Turbo problems

[hongo88]

Greetings Everyone,

I am having issues diagnosing a problem with a VGT. This is the story and I thank you in advance for any type of help: This truck had 2 camshafts, all valve guides and injector o rings replaced due to oil found at fuel and exhaust port. VGT was replaced as well because it was licking oil from seal and I opted to install a used one that I found for a good price locally. This used turbo was calibrated using insite and it passed both test. After installation a force regen was done to check if turbo was opening more that 80% to create enough heat to start regen and it did. After a successful regeneration, truck was put on the road and worked for about one and a half months and turbo stopped opening more than 50%, therefore, I took actuator out and check the end play of the leg and it was seized. I concluded and that was probably my mistake, that used turbo was bad from the beginning and that's why it gave up in such an early time and I didn't do any further testing :s. I ended up installing a re manufactured from a local dealer and again did all the same procedure and it worked like a charm, no complains from driver etc. Now 2 months later, same thing happens, turbo it only opens gate to 55% is not seized, but it don't open enough to make regeneration. What could be causing this problem?

Any help is good. Thank you in advance.

[Unilevers]

only 2 things seize the vgt, High exhaust temps or a shitty rebuild. I doubt you have had 2 shitty rebuilds in a row.

[Rawze]

I have also seen repeated turbo failures if there is chunks of carbon buildup in the egr cooler, the egr valve, or any other exhaust or egr circuit.

You say it has oil leaking into the exhaust manifold. This will get into the egr cooler + egr valve and make diamond-hardened chunks of carbon (hardened soot from the oil and heat). - Later, these chunks of hardened carbon will come loose and make their way into the turbo exhaust housing one way or another and cause problems like destroyed exhaust impeller, damaged VG housing and packing in around the VG ring, limiting its movement.

I have seen guys destroy several turbochargers in a row in only a few days time due to this problem alone.

The solution is to replace the egr cooler or at least pull it off and clean it out really well with heavy solvents to remove the chunks of carbon/soot. - Either way, it has to come off.

Also, if the egr cooler is impacted, the egr valve, egr piping, and intake needs the same treatment to remove all of it. - Sometimes a truck will run for so long with oil seepage + carbon issues that it will even build up behind the ecm in the head around cylinder #2 real bad and cause the engine to run unbalanced under load.

A chunk of carbon in the egr cooler, intake, or egr circuits is not worth destroying a turbo, so I generally tell others to just replace the egr cooler if it looks like it is packed with carbon + clean out everything egr, exhaust,intake -related really well including removing the intake manifold and checking the intake of the head itself if necessary. Once a problem with carbon chunks happens, it gets everywhere in those circuits and it is hard to get it all out. -- It only takes a single missed piece of it lurking somewhere like the CAC or other place for yet another turbo to get destroyed.

- How can it get from the egr cooler around to the cac? -- every time you shut off your engine, your turbo does several 'cleaning cycles' for the vg ring. If a person listenes closely, they will hear all kinds of "fauf, fauf,fauf" sounding turbulences occurring while the engine is shutting down. Air flow goes in multiple directions in the egr, exhaust, and intake circuits. Some trucks are worse than others for this, it depends on the design of the CAC, ect. of a particular make/model vehicle.

[hongo88]

(01-25-2019 )Unilevers Wrote:  only 2 things seize the vgt, High exhaust temps or a shitty rebuild. I doubt you have had 2 shitty rebuilds in a row.

Do you think that a bad calibration on injector will cause that much heat to seize VGT?

[hongo88]

(01-25-2019 )Rawze Wrote:  I have also seen repeated turbo failures if there is chunks of carbon buildup in the egr cooler, the egr valve, or any other exhaust or egr circuit.

You say it has oil leaking into the exhaust manifold. This will get into the egr cooler + egr valve and make diamond-hardened chunks of carbon (hardened soot from the oil and heat). - Later, these chunks of hardened carbon will come loose and make their way into the turbo exhaust housing one way or another and cause problems like destroyed exhaust impeller, damaged VG housing and packing in around the VG ring, limiting its movement.

I have seen guys destroy several turbochargers in a row in only a few days time due to this problem alone.

The solution is to replace the egr cooler or at least pull it off and clean it out really well with heavy solvents to remove the chunks of carbon/soot. - Either way, it has to come off.

Also, if the egr cooler is impacted, the egr valve, egr piping, and intake needs the same treatment to remove all of it. - Sometimes a truck will run for so long with oil seepage + carbon issues that it will even build up behind the ecm in the head around cylinder #2 real bad and cause the engine to run unbalanced under load.

A chunk of carbon in the egr cooler, intake, or egr circuits is not worth destroying a turbo, so I generally tell others to just replace the egr cooler if it looks like it is packed with carbon + clean out everything egr, exhaust,intake -related really well including removing the intake manifold and checking the intake of the head itself if necessary. Once a problem with carbon chunks happens, it gets everywhere in those circuits and it is hard to get it all out. -- It only takes a single missed piece of it lurking somewhere like the CAC or other place for yet another turbo to get destroyed.

- How can it get from the egr cooler around to the cac? -- every time you shut off your engine, your turbo does several 'cleaning cycles' for the vg ring. If a person listenes closely, they will hear all kinds of "fauf, fauf,fauf" sounding turbulences occurring while the engine is shutting down. Air flow goes in multiple directions in the egr, exhaust, and intake circuits. Some trucks are worse than others for this, it depends on the design of the CAC, ect. of a particular make/model vehicle.

Thank so much, for such a good explanation on this subject.

[flatbed94kid]

I think Rawze says to use carb cleaner rather then brake cleaner as I think brake cleaner can make the soot stick more vs the carburetor cleaner.

[hhow55]

I use Palmolive dishwashing liquid, to clean my egr piping. Yes it work's