Isx15 2250 choking

[Samvelm83]

Anyone had this problem?
Cranks then slowly dies. Happening 3rd time. After many attempts it fires up, sometimes it takes minutes sometimes it takes hours. Once it gets running no error codes and runs well all day.
Don't know from where to start.
p.s. CHECK ENGINE - nox sensor is bad. (No other error codes)

https://youtu.be/HtSXdWRqU_E?si=0qQEZKG8yqNbwiHC

This is data after getting it running

[windowrattler]

To me it seems like you lost fuel prime and it's firing on what fuel is left in the rail. Does the lift pump run when key'd on?

[Samvelm83]

(12-10-2023 )windowrattler Wrote:  To me it seems like you lost fuel prime and it's firing on what fuel is left in the rail. Does the lift pump run when key'd on?

Honestly didn't check lift pump at that moment.
But what I did check is that fuel rail pressure commanded vs measured were pretty much the same PSI.
If the lift pump failed at that moment would there be a pressure in the rail? And would there be any erro code referring to the lift pump? Any thoughts?

[Colter]

Your exhaust pressure sensor is reading completely out to lunch, replace it and check tube isn't plugged, should match baro with engine off, where its idling there it should be around 40, unlikely the full story but will have a big impact on how it runs and points towards an unhealthy engine

[Rawze]

Just some speculation...
could also be the the turbo locked up at 100% closed, choking the exhaust so badly that it cannot stay running.

someone could test this by removing the fitting/pipe clamps and bellows (or at least make a gap) where the manifold makes a u-turn and goes into the egr cooler. Open up the exhaust manifold so that it can breathe ... and see if the relieved pressure from the manifold allows the engine to keep running.

[Samvelm83]

(12-11-2023 )Rawze Wrote:  Just some speculation...
could also be the the turbo locked up at 100% closed, choking the exhaust so badly that it cannot stay running.

someone could test this by removing the fitting/pipe clamps and bellows (or at least make a gap) where the manifold makes a u-turn and goes into the egr cooler. Open up the exhaust manifold so that it can breathe ... and see if the relieved pressure from the manifold allows the engine to keep running.

If the turbo is locked up then the acutator would throw an error code, right?

[NDISX15]

(12-11-2023 )Samvelm83 Wrote:  

(12-11-2023 )Rawze Wrote:  Just some speculation...
could also be the the turbo locked up at 100% closed, choking the exhaust so badly that it cannot stay running.

someone could test this by removing the fitting/pipe clamps and bellows (or at least make a gap) where the manifold makes a u-turn and goes into the egr cooler. Open up the exhaust manifold so that it can breathe ... and see if the relieved pressure from the manifold allows the engine to keep running.

If the turbo is locked up then the acutator would throw an error code, right?

Not necessarily. I've seen many turbos/VGT Actuators fail in 90+% closed positions before and never trip a light/code. Last one I saw was 100% locked closed and only way we got it to run long enough to get it indoors was to pull the bellows off the manifold to the EGR cooler so it could breathe. Pulled the actuator and the turbo VGT was seized at 93%. If it starts and runs after removing that bellows, pop the VGT actuator off and verify the position of the turbo. Or try to run the VGT Hysterisis test in Instite.

[Samvelm83]

(12-11-2023 )NDISX15 Wrote:  

(12-11-2023 )Samvelm83 Wrote:  

(12-11-2023 )Rawze Wrote:  Just some speculation...
could also be the the turbo locked up at 100% closed, choking the exhaust so badly that it cannot stay running.

someone could test this by removing the fitting/pipe clamps and bellows (or at least make a gap) where the manifold makes a u-turn and goes into the egr cooler. Open up the exhaust manifold so that it can breathe ... and see if the relieved pressure from the manifold allows the engine to keep running.

If the turbo is locked up then the acutator would throw an error code, right?

Not necessarily. I've seen many turbos/VGT Actuators fail in 90+% closed positions before and never trip a light/code. Last one I saw was 100% locked closed and only way we got it to run long enough to get it indoors was to pull the bellows off the manifold to the EGR cooler so it could breathe. Pulled the actuator and the turbo VGT was seized at 93%. If it starts and runs after removing that bellows, pop the VGT actuator off and verify the position of the turbo. Or try to run the VGT Hysterisis test in Instite.

Aftert getting it running I did the VGT Hysterisis test and it passed.
I believe the primer pump is the problem.
When the primer pump fails does it throw any error code?

[tree98]

Turn the key to the on position with the engine not running. If you don't hear the pump that means it isn't working and needs replaced. Primer pump will make noise for about 2 minutes and then shut itself off if it's functioning properly.

You seem to be hung up on everything needing to produce a code. Unfortunately it's not always that easy.