Originally Posted by PROSTREET80

We have had some problems with the newercummins DPF but non DEF engines doing this somtimes. Somtimes it is in the software calibraition. you need to let cummins or a dealer look at it and see if it has the lastest update in the ECM. What is acutually happening is the turbo acuator is closing down to much under a full load and almost shutting all the exhaust flow off for a few seconds.

The popping and jerking noise you hear usaually back through the breathers if you have outside breathers is the boost or intake pressure side of the turbo rushing back and coming out the breathers which also causes the boost to drop out some then come back. The two things we do is first check for the lastest calibration from cummins to fix this problem and if it already has it I have recalibrated the acuator and fixxed it a few times but if neither of these work a new turbo which is the last resort will fix it. It is a real pain and im not really sure why it slamms the exhaust vanes back that hard and almost chokes the engine out. It could be the vanes sticking some but usually it will throw a code for that saying VGT not responding or nozzle position is out of calibration. The three or four times we have had this problem and i check the travel on the acuator arm it will move both ways all the way on the gauge cummins sends with the new acuators so in our case the vanes being stuck or sticking wasnt the problem.

But I do know that one of these three things will fix it for sure. Its almost a little to complex of a system to work right all the time and if any thing is wrong inside that VGT turbo it just kills performance on these isx engines and causes problems. Even though i work on these engines alot I really hate VGT turbos.

Good luck and I hope you can get it took care of.

my understanding is the holset turbo is poorly designed and built. they don't last very long.

towards the end of my turbo life. only issue i had was climbing the hill and all of a sudden had almost no power. till i changed gears.


a lot of the times in the lower gears, i couldn't even rev past 1700 till i changed gears.

so i suffered power issues, but not a jerking engine becuase of the turbo. mine was ecm shorting out. and it only happened on climbs. just like his.

oh yeah. 05 w9 isx 450 with only egr

All im saying is our trucks do jerk and cuttout up the hills loaded when they have this problem i just decribed. Obviously yours had a electrical short causing the problem. And 80 percent of the time a short in the wiring will cause a engine light but there is about another 20 percent of the time it won't depending on where it is and which side of the ECM it is on. These turbos can cause alot of problems that most hasn't seen before untill it happens to them.

snowwy it sounds like your turbo locked up and wasn't in the right spot to run good. Some lock up and still make good boost depending on what percent closed it locks up say around 60 to 70. yours probably locked up around the 30 or40 percent range and when it does that it makes the exhaust chamber inside the turbo so big it can't make the velocity to spool it very hard and in return it has low power and low boost.

don't know about hte locking up part. but that's possible. everything is defenitly worn out.

the shafts were scarred causing looseness where they ride on the bearings. just about every vane in the thing had some very slight nicking. one of the vane assembly was bent where the vanes were supposed to be straight. and of course. the famous crack in the plate. although i only had one.

according to the guy rebuilding it. mine was very good shape compared to others he's seen.

everything is getting replaced though. minus the housings. and actuator. i thought about replacing the actuator just to be done with it. even though there's need to. but this truck really needs to start making money again. the bills are falling behind.