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yionkin81

2012 t800 isx15 cummins 18 speed
Turbo spooling up and down at idle
Rough idle.

On cold start this issue will start about 45sec-1min after start
It will stop spooling up and down on its own after 7 maybe 10 mins of running.
As soon as I touch the skinny pedal it starts running rough and spooling up down again.

There is grey and blue smoke coming from exhaust when it's spooling up down and rough running.

When spooling up down stops smoke clears and engine smoothes out but still not fully smooth.

One of the things I noticed in the log is:
When turbo spooling up down at idle and rough running:
-the EGR Differential Pressure Sensor is reading -(negative 0.160 to negative 0.060) ratio
-exhaust gas pressure reading 300-400kpa
-EGR valve commanding and responding at 0%
-Turbo actuator commanding and responding at 88+%
-EGR orifice pressure -2 to 0.5 kpa fluctuating
-intake manifold pressure 1-2kpa
-barometric pressure steady at 102.5kpa

When turbo stops spooling up down and idle smoothes out:
-the EGR Differential Pressure Sensor is reading -0.500 to 1.500 ratio
-exhaust gas pressure reading 110-130kpa
-EGR valve commanding and responding at 14%
-Turbo actuator commanding and responding at 40 to 60%
-EGR orifice pressure 4 to 10 kpa fluctuating
-intake manifold pressure 4-8 kpa
-barometric pressure steady at 102.5kpa

Checked everything and nothing making it stop. Have cummins insite log if anyone can read it.

-New turbo and actuator, calibrated with Cummins insite
- no CAC leaks on boots, compressor hose, crossover, stock CAC
- all pressure sensors, IMAP and egr diff pressure sensor are new
- passed injector test on all cylinders
-egr valve responding as commanded
-turbo responding as commanded
-EGR cooler 100% efficiency as reported on insite
-did 2 Regens. Each took 1.5 hrs
-DPF soot normal (pressure difference of 2kpa)
-Cleaned EGR Valve
-all port sensing passages have been blown out and cleaned
-exhaust pressure tube and port cleaned and clear
-EGR cooler, EGR valve and DPF have been recently replaced (about 4k hrs ago)

NOTE: NO engine error codes at all!!

What else can I check??
What causes EGR Differential Pressure to read in negatives ratio??
What causes exhaust pressure to triple of EGR cooler is 100% efficiency?
Or if anyone had this issue what solved it?

Where the truck is located I don't have ability start taking all aftertreatment exhaust components apart for full tuneup. That will happen when I get it home (about 900kms)

Thanks!

Yevgeniy ionkin

hhow55

I tend to think you may have a restriction in the Charge Air Cooler.

mikkhh

Are all those replaced sensors genuine oem parts?

DPF is used or aftermarket? Or has it been properly dry cleaned in a kiln?

Rawze

#1 is the enigne de-mandated?. (deleted)?

#2. Is the program exactly the one that belongs to the engine ser#?... or some other HP program?.

#3. Is that program the latest version from cummins?.;

Also,. here is some related information...

some related posts that came up in a search ....

http://rawze.com/forums/showthread.php?t...4#pid14784

http://rawze.com/forums/showthread.php?t...57#pid1057

http://rawze.com/forums/showthread.php?t...08#pid6508

http://rawze.com/forums/showthread.php?t...30#pid9330

http://rawze.com/forums/showthread.php?t...1#pid11711

yionkin81

I will take boots off and inspect CAC.

DPF was previously replaced by original owner with OEM. I didn't take it off to inspect or manually clean it. Don't have that ability right now.

#1. Truck is not deleted. Everything is intact and functioning, no codes.

#2 and #3 I am not sure on this. How can I check this? My SN is 954243 Engine from factory is 605HP 2050Torque

Can I download latest software if required?

Thanks