ISB 6.7 crankcase pressure fault code

[Ryda]

(05-24-2020 )Ryda Wrote:  

(05-23-2020 )Lonestar10 Wrote:  crank case pressure can be caused by a failed aircompressor, failed cylinder(s), and Failed turbo shaft seals as far as i can remember....and possibly valve stem seals if the valve guides and seals are completely blown out.

Thanks Lonestar10, I'm hoping/thinking it's not the turbo since the turbo and actuator were both replaced last august and currently have only 25-30k on it. I didn't know what to look for, but when I removed the air intake to do the oil cooler, nothing suspicious was there, it looked clean but i didn't try to spin the turbine. While driving the turbo spins up to 80,000 rpm so I'm thinking it's doing it's job.....forgot to mention that the truck seems to hang in gear when gearing down (it's an automatic). It builds air fully, but it does so slowly, I'll have to monitor that more closely and see how long it takes to get to 120 psi from startup and try to check the air compressor more closely, and probably replace the governor. If valve guides and seals are blown, what would be the signs (visible or operation) of that?

I tried to do a cylinder cutout test using insite today and when trying to run on one cylinder, the truck cuts right off. So would that mean that my problem can be anything ranging from injector wiring to the cylinders themselves?