2006 CM870 high EGTs

[JBaird]

The dyno results show the engine to be solid. It was over fueling and only produced 28.1 pounds of boost. They were convinced the lack of boost contributed to the over fueling and high EGTs. They pulled the actuator off the the turbo disassembled and added approximately 4mm of shims between the housing and spring to tighten the spring up. It took 3 tries of adding and removed shims, but got the engine to produce 38 lbs of boost on a hard pull. The truck woke up and on anything over a 30% load the EGTs fell on average over 250 degrees. It seems like a cheesy repair, but the truck runs good.

[Peashooter67]

Look at your ambient air temp sensor and compare it to your three other temp sensors on a room temp engine in the morning.

Ambient air temp
Water temp
Intake temp
Air inlet temp

On a stone cold engine they all should be close to each other.

Also look at your intake pressure sensor and exhaust back pressure sensor as both should also be real close on a stone cold motor.

If any of these are off as in way off it will cause your motor to derate “maybe” and high egt.

Also comparing your estimated intake temp and actual intake temp.


My guess is one or more are way offf.

[Rawze]

(09-17-2023 )Peashooter67 Wrote:  ...
Also look at your intake pressure sensor and exhaust back pressure sensor as both should also be real close on a stone cold motor.
...

Actually, engine off and key-switch on, on a lot of cummins engine models, the intake manifold pressure sensor reads zero for "no boost" .. and the exhaust pressure sensor reads close to atmosphere pressure at the altitude your are at. These are not the same.

[Peashooter67]

Correct

Was cross in thought. Barometric and exhaust should read the same.