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Tractor with Codes and Random Shutdown
Tractor with Codes and Random Shutdown
I would like to be clear about this case, I was called for assistance after the dealer tech had worked a bit on troubleshooting,
Tractor was delivered to the dealer with <8 hours on the meter, machine would shut down (described as abrupt key off kind of event) at random.
Tech checked codes, had CAN comm faults and needed the cluster and engine software updated.
After software updates machine ran for 30 mins before shutting down, rechecked codes and had a CAN comm and also rail pressure code for exceeded maximum positive deviation limits (love the engineering speak).
Tech was focused on CAN comm fault, spent some time troubleshooting prior to contacting me.
After a long discussion over the course of a day or so, reviewing what had been done and what direction the diagnosis may need to go I made arrangements to visit the machine.
When I arrived at the shop we checked codes, again CAN fault and rail pressure, all connectors were checked secured, we checked the CAN resistance at the diag connector and had 59.9 ohm, so no need to chase the CAN code. On a side note the CAN code I suspect is caused by the scan tool which during the comm setup takes the ecm offline briefly.
Now time to focus on the rail pressure, started by clearing codes and connecting scope, decided to collect the rail pressure signal, high pressure pump metering valve amp draw and also PWM signal.
Started tractor up and it popped off right away, no lag or hesitation, machine idled fine, ran at idle for a few mins, no issue, capture attached.
moved RPM up to 1600 and it ran fine for a few more mins, moved to 2000 still no issue, moved to WOT 2400 and whoa machine shuddered and died. OK clearly demonstrated the issue.
Now that we see when the issue has occurred we took a second capture and threw in the CKP as it was an easy grab, we captured the shutdown event, at ~60sec. the rail PSI starts to drop, metering valve attempts to add fuel, rail PSI shoots up, metering valve cuts back (trying to control flow/PSI), rail PSI drops and engine cannot stabilize so it shuts down.
At this point I spend some time reviewing the capture with the tech, we discussed potential reasons for the shutdown, do we have a sensor that cant maintain correct signal? metering valve issue? high pressure pump issue? wiring problem or a fuel supply problem?
Earlier while doing some basic sensor checks we verified the 5volt supply and ground integrity, also did the unplug test on the sensor which drove the signal high so we know all sensor wiring is good.
So knowing the sensor wiring is good, we use the capture to verify the metering valve function, we can see the metering valve react to the rail PSI sensor signal, no odd signal on the control or on the amp reading, so I was relatively certain that wiring and valve are functioning as needed.
So do we have a sensor that has an offset/drift? We discussed swapping a rail pressure sensor from another tractor on the lot, however that would require tearing into an other new machine and I like to avoid that if possible.
One thing we didn't know is actual fuel supply pressure, there is no sensor and it requires a special tool set (which was not available) for taking these readings, so we decided to run the machine off a separate fuel source. We were fortunate that the line are quick connect which made the work fairly easy.
The fuel system supply starts at the bottom of the tank with a large thread insert/quick connect fitting, from there it goes into a sediment bowl, primary fuel and then secondary filter/water separator.
We dropped the main fuel supply line in the new source, started the machine up, once idle stabilized we ran it WOT... No shutdown, hesitation, no problem... We idled the machine back down, let it run for a few mins, I took a capture at WOT with the separate fuel source.
With this new turn of events I asked the tech to remove the fuel tank and we would need to start looking for some sort of restriction/blockage.
Once the tank was drained, pulled out the tech removed the supply fitting in the tank bottom and here is what was found.
It would appear that the flimsy line inside the tank was twisted during installation, the line was removed, all was reassembled and tank filled. Tractor was test operated for additional time with no further issues.
Thanks for reading..
Tractor was delivered to the dealer with <8 hours on the meter, machine would shut down (described as abrupt key off kind of event) at random.
- New Holland Workmaster 65
After software updates machine ran for 30 mins before shutting down, rechecked codes and had a CAN comm and also rail pressure code for exceeded maximum positive deviation limits (love the engineering speak).
Tech was focused on CAN comm fault, spent some time troubleshooting prior to contacting me.
After a long discussion over the course of a day or so, reviewing what had been done and what direction the diagnosis may need to go I made arrangements to visit the machine.
When I arrived at the shop we checked codes, again CAN fault and rail pressure, all connectors were checked secured, we checked the CAN resistance at the diag connector and had 59.9 ohm, so no need to chase the CAN code. On a side note the CAN code I suspect is caused by the scan tool which during the comm setup takes the ecm offline briefly.
Now time to focus on the rail pressure, started by clearing codes and connecting scope, decided to collect the rail pressure signal, high pressure pump metering valve amp draw and also PWM signal.
Started tractor up and it popped off right away, no lag or hesitation, machine idled fine, ran at idle for a few mins, no issue, capture attached.
moved RPM up to 1600 and it ran fine for a few more mins, moved to 2000 still no issue, moved to WOT 2400 and whoa machine shuddered and died. OK clearly demonstrated the issue.
Now that we see when the issue has occurred we took a second capture and threw in the CKP as it was an easy grab, we captured the shutdown event, at ~60sec. the rail PSI starts to drop, metering valve attempts to add fuel, rail PSI shoots up, metering valve cuts back (trying to control flow/PSI), rail PSI drops and engine cannot stabilize so it shuts down.
At this point I spend some time reviewing the capture with the tech, we discussed potential reasons for the shutdown, do we have a sensor that cant maintain correct signal? metering valve issue? high pressure pump issue? wiring problem or a fuel supply problem?
Earlier while doing some basic sensor checks we verified the 5volt supply and ground integrity, also did the unplug test on the sensor which drove the signal high so we know all sensor wiring is good.
So knowing the sensor wiring is good, we use the capture to verify the metering valve function, we can see the metering valve react to the rail PSI sensor signal, no odd signal on the control or on the amp reading, so I was relatively certain that wiring and valve are functioning as needed.
So do we have a sensor that has an offset/drift? We discussed swapping a rail pressure sensor from another tractor on the lot, however that would require tearing into an other new machine and I like to avoid that if possible.
One thing we didn't know is actual fuel supply pressure, there is no sensor and it requires a special tool set (which was not available) for taking these readings, so we decided to run the machine off a separate fuel source. We were fortunate that the line are quick connect which made the work fairly easy.
The fuel system supply starts at the bottom of the tank with a large thread insert/quick connect fitting, from there it goes into a sediment bowl, primary fuel and then secondary filter/water separator.
We dropped the main fuel supply line in the new source, started the machine up, once idle stabilized we ran it WOT... No shutdown, hesitation, no problem... We idled the machine back down, let it run for a few mins, I took a capture at WOT with the separate fuel source.
With this new turn of events I asked the tech to remove the fuel tank and we would need to start looking for some sort of restriction/blockage.
Once the tank was drained, pulled out the tech removed the supply fitting in the tank bottom and here is what was found.
- Fuel Supply Fitting
Thanks for reading..
-
ben.martins
- Pico Staff Member
- Posts: 544
- Joined: Tue May 16, 2017 1:02 pm
Re: Tractor with Codes and Random Shutdown
Thanks for sharing this Muttnjeff. Too often fault codes can lead us down the wrong path and having a clear diagnostic process will give the direction needed to find the fault. Would have been good to have seen WPS500 in the supply line, might have seen an increase in vacuum as the pipe was sucked shut.
Great work and thanks again for sharing.
Kind regards
Ben
Great work and thanks again for sharing.
Kind regards
Ben
Re: Tractor with Codes and Random Shutdown
Will keep that in mind, ironically the dealer did not have the recommended kit for checking fuel supply, however these machines have what I would call typical m/f quick connect fittings that many automotive aftermarket tool kits have...
Should've just wen t down to the local tool store I guess.
Should've just wen t down to the local tool store I guess.