Cummins ISX coughing

My Cummins M11 makes a sound that may be like what you are hearing, I have very high flow mufflers (rusted inside and not much baffle left LOL) when the turbo is under heavy load and I suddenly back off to change up a gear is when I sometimes hear the noise. maybe this is what you are hearing??? now that you are getting full turbo boost.

 

Probably the vanes in your turbo sticking. More than likely time for a new turbo. If you are out of warrenty i'd talk to Mr.Haney about maybe a PDI manifold and turbo.

 

What you're probably hearing is the air flow reversing or stalling. Think of the air as a column of water moving from the air cleaner through the turbo and into the engine. The turbo is a air pump(water pump) that moves this air(water column). The energy to drive the turbo(water pump) comes from spent exhaust gases exiting the engine. To add energy to drive the turbo(water pump) faster............you step on the fuel pedal. The extra fuel is burnt and sent out as extra energy to turn the turbo. If you are coming up through the gears and at every shift...........you take energy away from the exhaust, which takes energy away from the turbo(water pump) The column of air(water) coming out of the turbo(water pump) under pressure suddenly comes to a stop. but it still has pressure...........the suction side of the turbo(air filters) doesn't have any pressure..........you have no energy turning the pump/turbo..........the pressurized air wants to take the path of least resistance............this is the air cleaner........not the engine air intake manifold The air(water column) stops and reverses direction towards the air cleaner. What you're hearing is air movement. I'd say the new aftercooler you installed has less air resistance across the core. Most aftercooler have enough resistance across the core that it suppresses the noise and actually works as a #### to hold the air(water column) for making sudden changes in direction during gear changes. You want to change your shifting habits.........ease up on the throttle gently to lower boost slightly before you shift. Otherwise this sudden reversal of air is hard on turbos after awhile. Also with this being an ISX with the VG turbo, you may want to see if it's functioning properly. You maybe having a problem the variable geometry vanes in the turbo and at times are spooling the turbo to fast for the work conditions..........the turbo is still reversing air flow through it. Eventually it's going to break the through shaft between the turbine wheel and compressor wheel............this can be a very expensive repair if this happens.

 

Good explication of turbo stall. I've heard it a few times on my isx's during up and down shifts. Like you said if you feather the throttle you can stop it from doing it. Very good as usual Mr. Haney

 

you need to downshift sooner, and lift off the pedal slower/smoother and it will no longer make the stall sound.

you must be lugging it right back pretty severely to make it do that, mine needs full load and rapid rpm drop to around/just under 1000 to do it.

 

i have a 06 volvo with cummins abaoute 1 year a go my truck start doing that to i ask a lots of mechanics a lots of opinions this and that is the egr is getting bad the more you drive the more start doing it ,what i did in one day i gest disconected and all my proablems stop right there.

 

I know this is an oldie, but, I have a 2007 Volvo with the same issue. Just started a few weeks
back. Someone mentioned the turbo shaft might come apart. IF the issue is in the VGT turbo
vaines, why would the shaft come apart.

Thanks

 

Had the issue for a while only got worse. Invested into a new turbo.. ran new again