Skyjack SJ45T won’t start

[Skidloadertech]

Hi, I have a Skyjack SJ45T s/n 980024 in the shop. It’s driving us crazy. It has a Deutz 2011 engine. The customer had it out on rent and the operators ran it out of oil and toasted the engine. He found another rebuilt 2011 engine that is a newer version but technically the same. A shop swapped it out for him , they swapped out all the sensors, engine harness, fuel actuator, everything that tells the ECM anything. It has never started since.
If the fuel rack actuator is removed, and the throttle is run manually it runs great. So we know that we have an issue with the electronics. The thing is, all the test check out. The actuator ohms out correctly, the wiring harness ohms out. We installed a new actuator and a different ECM from a twin machine. It must be something in the wiring harness that we are missing.
If anyone has experience on these machines please chime in here. I NEED Help

 

[MarshallPowerGen]

So not getting any movement from (or signal to) the actuator while cranking? CANBus resistors check out?

I remember having issues with the ECM for a couple of the Deutz powered lifts getting their engine speed signal from the engine alternator and that causing running issues (but it's been a couple of years and a lot of equipment in between, so I don't remember the exact problem).

 

[Txhayseed]

Did the harness and sensors come with the reman engine or is it the factory harness ? Ecm pinouts can change from one revision to the next and can be manufacturer specific. Since you know it runs with out the actuator your either missing the signal due to harness differences or the ecm is not commanding the outputs. Swapping ecms on late model off road diesels is not always a sound diagnostic procedure these days. Are you not getting any codes ? I would think you get several out of range codes or can bus errors to help point out where you are going to need to look

 

[JLarson]

Yeah I'm not sure I'm clear either which harness are you trying to use and where's you get it?

Also is it your (I mean you work for the rental company) machine?

 

[Skidloadertech]

The harness that was swapped is from the old engine along with all of its sensors. Basically, the difference between the 2 engines is : the original engine installed by Skyjack has a electronic rack actuator instead of a fuel shut off solenoid. To run that actuator it has an ECU, speed sensor, oil pressure sensor, and temperature sensor all easily moved to the replacement engine with no modifications.
I am getting a feedback error 50. This would come from the actuator itself the only sensor that reads rack position is part of the actuator. I have wiring diagrams from Deutz and Skyjack. I have ohmed out all the wiring and checked all pins. I went so far today as to make up a temporary harness from the ECU to the actuator (only 5 wires).
This is an EMR2 unit so not exactly a late model machine. The actuator coil circuit is PWM. I have quite a bit of experience with these engines and from the engine side it seemed everything was there. (Although it keeps giving the feedback error) This afternoon however in trying to calibrate the rack yet another time I think I might have discovered something. It seems like maybe the rack is not quite moving to full fuel. When you do a calibration you pin the rack to full fuel. When putting in the pin, I caught on that it is forcing the rack farther over. I think that is messing with the rack cal. Maybe one of the fuel pumps is not installed quite right???The day got all…..

 

[Txhayseed]

Sensors attached to the engine provide control unit electron-
ics with all relevant physical parameters In accordance with
information of the current engine conditions and precondi-
tions (throttle position etc.), the EMR2 controls an actuator
that operates the control rod of the injection pump and thus
doses the fuel quantity in accordance with the performance
requirements.

Exact position of the regulating rod is reported back and, if
necessary, is corrected, by means of the control rod travel sen-
sor, situated together with the rotation magnets in a housing
of the actuator.
Info per deutz.

 

[Txhayseed]

I really can not be more help. Situations like this particular one would require my brain and eyes to be right there with you. Was the ecm swapped over with the donor engine as well ?