871 Low Boost / VGT Commanded

[Smooth]

Kinda jumping gun here but wanted to throw this out there see if anyone else has input that might help

CM871 - 2010 - International ProStar DayCab - ECM has M&M was done year ago and truck has been fine since then. Now Low Boost, will only build 8-9 Lbs. Replaced Turbo(turbo would not calibrate) , Calibrated during install etc. New turbo had no problem calibrating as the old turbo did so did not replaced the Actuator.

Now noticing
Turbo Actuator Position Commanded is reading 0 !! NEVER MOVES DURING OPERATION
Turbo Actuator Position Measured is reading 48% at Idle , 1800 RPM went down to low as 27 %

Going to replace the Actuator and check the plugs/wiring.

Any other ideas or thoughts.

Thank you

[Rawze]

check to ensure the engine harness J1939 has 60-ohms on it properly with everything connected and power off for more than 2 minutes.
ref: http://rawze.com/forums/showthread.php?t...8#pid72528

It should have no issues calibrating with a proper de-mandate on it. Maybe also need to also do a proper turbo mechanical inspection.

[Smooth]

I am getting zero at J1939 weatherpack and have no Faults of any type active or inactive on Engine Side.

(10-03-2022 )Rawze Wrote:  check to ensure the engine harness J1939 has 60-ohms on it properly with everything connected and power off for more than 2 minutes.
ref: http://rawze.com/forums/showthread.php?t...8#pid72528

It should have no issues calibrating with a proper de-mandate on it. Maybe also need to also do a proper turbo mechanical inspection.

[Smooth]

(10-04-2022 )Smooth Wrote:  I am getting zero at J1939 weatherpack and have no Faults of any type active or inactive on Engine Side.

(10-03-2022 )Rawze Wrote:  check to ensure the engine harness J1939 has 60-ohms on it properly with everything connected and power off for more than 2 minutes.
ref: http://rawze.com/forums/showthread.php?t...8#pid72528

It should have no issues calibrating with a proper de-mandate on it. Maybe also need to also do a proper turbo mechanical inspection.

[tree98]

Missing a terminating resistor?? Possibly a bad actuator, they have a terminating resistor inside them.

[Mr Hagg]

back probe harness at turbo see if you are gettting 60 ohms... then unplug it see what you get... You should get 120 on the acuator and 120 on the harness....let us know what you get

[Rawze]

(10-04-2022 )Smooth Wrote:  I am getting zero at J1939 weatherpack and have no Faults of any type active or inactive on Engine Side.

then you are measuring it wrong.. or you are trying to measure it before it is completely shut down.. or the network is screwed up in some way.. take your pick.

[Smooth]

Update and Correction - Did not have solid connection eariler

J1939 is Ohm 60 When unplug the Actuator at the J1939 120 Ohm

Plugged the J1939 back up - Unplugged the Actuator and measure the actuator itself 120 Ohm

Now where the actuator plugs into the harness on Passenger side is reading 171-173 Ohm

Both Terminating Resistors have been checked - 120


Still have No fault codes and When monitoring from in-site still getting zero on Parameter - Turbo Actuator Position Commanded

I cannot imagine anyone has tampered with this ECM, but going to double check that. It has OG 871 M&M with no changes made from the OG M&M

[Rawze]

In a hard pull?... and what positions is turbo "measured" going to?... how much boost?. and what is the fuel flow doing?... and what is the engine state parameter saying?... and what is the turbo RPM reading?.

If the "measured" is responding properly then you may just be barking up the wrong tree by looking at the "commanded".

sounds to me like you have a massive boost leak (or exhaust restriction, etc.) somewhere?.