Working on a Kohler Command Pro 26 EFI in a 2002 Exmark. It has an intermittent starting issue. When it will not start the MIL light stays on indicating a issue with the speed sensor. The engine has the Bosch injection system. Replaced the speed sensor and set the airgap but the issue still occurs about every other time you try to start it. It is now showing a Code 21 - Loss of Synchronization. Horizontal mount engine with pumps running off the front so I am wanting to avoid pulling the engine and cover if we will just end up scrapping the 20 year old mower because of a sheered flywheel drive key anyway. Am I looking at a flywheel issue or is it something much simpler that I am overlooking.
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Kohler Command Pro 26 EFI not starting
- Thread starter AS2016
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Export threadThe diagnostics hints to a possible misfire or incorrect spark plugs used. Also could be an issue with the grounds. I don't think a sheared flywheel key would be likely since there is no direct connection to cause a sudden stop of the flywheel, unless the flywheel has been removed and then not torqued properly.
I am guessing the sheared key is unlikely as well. I have not seen anything that shows that it has been removed at least recently. Only other issue is that after replacing the speed sensor and running for 10 to 15 minutes it seemed to have a sudden loss of power and run slightly rougher. Never died and could still mow but you could tell it was not right. Stopped and restarted and after about 30 seconds it smoothed back out and has been fine since. Would that be the ECU adjusting the fuel and would it be related?
That almost sounds like the misfire related issue with the synchronization issue. Running on one cylinder will cause loss of power and rough running issue. Faulty spark plug or ignition module going goofy.
I am leaning toward it being the ignition module or one of the wires in the main ECU connector. Every time that you crank it and it will not start the MIL light stays on and there is no spark. If you crank and the light goes out it starts a split second later. Kohler manual says pins 9 and 10 are the circuit related to the code 21 error, but it also lists the flywheel issue as being one of the main reasons for that code as well.