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The older commander 11/15 didn't have knock sensors . When they started using the detuned maverick engine in 16 or 17 was when they added the knock sensor.

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Discussion Starter · #22 ·
I don't know how the engine can detect knocking.....but I don't know everything. You said fuel pressure was good, but how long did you monitor it? Was it missing at 51psi? FWIW, dielectric grease does not insure a good connection. It is non-conductive. It's function is to seal/protect the metal connector components from moisture intrusion, oxidation, corrosion. Limp mode shouldn't make it misfire, just limit rpm/speed. If it runs good for a minute, then poor, I'd wonder is it starting to starve for fuel? Or injecting too much, starting to foul a plug? Spark check on both cylinders again will tell you something.
i wondered that too, that it might be starving or fuel. but while it runs on both cylinders it ran well even with wide open throttle. which seems to say the pressure is not dropping. I would test it but I don't have a setup for that right now.

acefire is right. mine doesn't have a knock sensor. =(

i wish there was at least an error code to work from. I could change the plug wire too. It is odd that it drops in half. That points to it doing it on purpose. Not just a random short to ground. If you can think of anything to test I will try that.

I am actually running out of ideas for now. Not getting error codes is making this a lot harder than it should be.
 

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Discussion Starter · #23 ·
I just checked it shows the front and back cylinder are firing at 600 at idle. as though it is alternating between the two cylinders. It is idling at 1200 though. but you can tell it is really weak when you gas it. I think I am going to call the dealership tomorrow. Maybe someone there can atleast make a suggestion of where to look.
 

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I got to thinking about ignition pulse count. 600 fires per minute (per cylinder) should be normal at 1200 rpm. A 4 stroke engine fires once every 2nd revolution of the crankshaft.
 

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Discussion Starter · #25 ·
I got to thinking about ignition pulse count. 600 fires per minute (per cylinder) should be normal at 1200 rpm. A 4 stroke engine fires once every 2nd revolution of the crankshaft.
You are correct. I am using a trail tech and it is set to 4 stroke so it takes that into account. When it first starts it says 1200 or so... for a while, then runs rough and go to 600 per cylinder.
 

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Discussion Starter · #26 ·
took it to the dealership. What a complete waste of time and money. Injectors are leaking so they want $900 to fix that before they troubleshoot the electrical problem. I will never go to Freedom Powersports in McKinney again. I will replace them myself of spray some carb cleaner in and be done with it. So now I am right back where i was before with the cylinder firing at half the rate.
 

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That sucks you can get the Bosch injectors to fix that part at any auto parts store. Then your looking at hr or less to switch then out. So that should save ya 700$ minimum.

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Maybe the leaking injectors are the problem, fouling the plugs. Cylinders firing at 600 per 1200 rpms is normal. You even said in an earlier post that you pulled the wire on a cylinder when it was running rough and got shocked.
 

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What about a broken valve spring, or sheared flywheel key, since it is rebuilt did you triple check the timing?

I do believe the motors with no cam position sensor use an ecu that can detect what stroke the motor is on by how the crank slows down on the compression stroke. So I wouldn't be surprised if it can also detect knock?

I worked on an 800 rzr once and sometimes it ran amazing and next time you got in it and it ran like crap. It had good compression, good spark, good fuel pressure, injectors were fine. I put a used ecu in it no plug wires. Nothing helped. I had pulled valve cover to make sure a lifter wasn't collapsing since it uses hydraulic lifters. Also wanted to make sure it hadn't ate a cam lobe. I had also made sure the oil pressure relief valve wasn't stuck. Everything checked out. In the end I pulled the valve cover again and found a valve spring broke.

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