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2015 M8000 No Spark

Hi. This is my first post here. I’ve had a couple Cats for years (90 EXT and 01 Mtn Cat 800 carb) and since I haven’t used them in years, I almost sold the whole mess this year until I realized I would be done with it … well forever. I’ve recommitted, went out and bought a 4-place enclosed trailer and am trying to get the kids into it now that they’re a bit older and winter sports aren’t such a drain. I also picked up a ‘15 M8 162 for a great price which the owner had starting problems with and sold cheap (advertised as an Arctic Crap ;)). He had replaced the stator and ECU with new units. He also had a new voltage regulator that had not arrived yet, but that would have been next.

When I looked at the sled, the owner was able to start it by dumping some fuel down the cylinder but it would die like it wasn’t getting fuel. He also had the key switch unplugged and the e-start side on the keyswitch lead jumped (non e-start sled). I figured this would be a fairly easy fix like a TSS or something else along those lines. I got it home and tried priming it again but had no success. Pulling the rope did nothing - no burp, no light flicker, no dash flicker, etc. I took the hood off and found the fuel pump unplugged. Plugged that back in and still nothing. I then put an inline spark tester on it and saw I was getting no juice. Since then I have taken the whole damn thing apart to check various connections for bad grounds including:
  • Unplugged TSS
  • Unplugged kill switch
  • Unplugged key switch
  • Removed both right and left switchgear and unplugged hand warmers
  • Removed pipe/can and examined harness for chafing at zip-ty points
Also:
  • Tried swapping ECU’s as old one was included
  • Have NOT swapped stators
  • Disconnected chassis ground and found coils grounded with ECU plugged in but not grounded when ECU not plugged in.
  • Tested fuel pump with 9V battery. Works fine. Also spits fuel when rope is pulled.
I’ve probably forgotten some other stuff I did trying to trace out a ground. I’ve gotten a service manual and looked through it. A couple of questions besides the obvious what the hell am I missing…
  • This is an open ground system meaning anything grounds besides the chassis ground and it kills the sled, right? Have I made a mistake simply leaving the TSS unplugged and removing all possible ground points? I checked continuity on the TPS micro switch as well as the kill switch and key. All tested good.
  • I did not see a stator test section in the 2015 2-stroke service manual I picked up off of Country Cat. Am I missing it? I found another post where a section of the 07 M1000 manual was posted and the stator test listed was exhaustive.
  • Did Arctic Cat do away with peak voltage testing specs in newer manuals? I noted the M1000 manual had a peak voltage test process which the 2015 manual did not. I planned to follow the M1000 manual process unless I’m told different.
  • Do any sensors possibly kill spark altogether instead of just going into limp mode? Like an oil level sensor or temp sensor? I’m prepared to test each but I don’t know that isn‘t a waste of time.
  • Would the sled show spark with the hood off and unplugged? I set the hood next to it vertically with it plugged in. Since then I’ve ordered the 6’ harness extension so I don’t have to worry about it in the future. Just wondering.
The previous owner was honest with me and said this electrical stuff seems to be a bit of an issue with the mid 20teen sleds, almost like AC got cheap on their component supplier. When it ran it was great and if I were to find it I’ll have a fantastic sled - but I have to find it first.

It’s driving me crazy that obviously he started it so what would have changed between then and me first pulling it? My only guess is that a bumpy tractor ride on a pallet and hercing it into my trailer would have potentially changed a ground point… but I’m still stumped.

I’m sorry for so many questions. Since this is my first EFI sled I would be tempted to haul it to the dealer, but we have no dealers for quite a distance around us now that the herd was thinned a few years ago. I really prefer to fix my own stuff regardless, but now I‘m seeing to really do it right from top to bottom takes another $1800 for a CATT II unit. :oops:
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Anyway, I would really appreciate any assistance the smarter/more experienced heads can provide.
 
I have had similar issues with these sleds and usually comes down to an issue with wire harness. Rubbed through or bad ground. Also had issues with fuel pump connector not making good connection. Try running fuel pump off a separate battery and see if it comes to life. Even had the fuel pumps stick after sitting for a long period. Jumping with a battery sometimes gets them going again. Good luck. Great sled when running.
 
I have had similar issues with these sleds and usually comes down to an issue with wire harness. Rubbed through or bad ground. Also had issues with fuel pump connector not making good connection. Try running fuel pump off a separate battery and see if it comes to life. Even had the fuel pumps stick after sitting for a long period. Jumping with a battery sometimes gets them going again. Good luck. Great sled when running.
Thanks for the encouragement. Going from the old MC to this will be technological leap.

I did check the pump with a 9V battery running it forward and backward and also by pulling the rope. Spits a healthy fuel amount. It takes a lot less juice to run that fuel pump than jump a spark gap, so I’m leaning towards a ground issue or something messed up in the magneto.
 
i think i saw this deal on craigs and thought about buying it myself. my thought was if it ran with gas down the plug holes, then it must jusst be an issue getting the fuel to the cylinders. like injectors or something. now i see he had fuel pump unhooked and wires bypassed. so you just hooked them back up like stock and now no spark? the sled should run with the key switch unplugged, nothing needs to be jumped. theres a connector where people sometimes hook a plug in tether into, im sure youve looked at all the conections tho... good luck
 
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i think i saw this deal on craigs and thought about buying it myself. my thought was if it ran with gas down the plug holes, then it must jusst be an issue getting the fuel to the cylinders. like injectors or something. now i see he had fuel pump unhooked and wires bypassed. so you just hooked them back up like stock and now no spark? the sled should run with the key switch unplugged, nothing needs to be jumped. theres a connector where people sometimes hook a plug in tether into, im sure youve looked at all the conections tho... good luck
Yeah I don’t know what happened between then and now but I’m halfway there after this afternoon. One of the pulse coils was whacked up and had about an eighth-inch air gap. Bent it down to .020” and I’ve got spark in both cylinders. I’ll put it back together tomorrow and see if fuel is solved too. I do have a new TSS bushing kit here as that still might be a culprit.
 
Unplugging handlebar harness eliminates TSS and kill switch as culprits if it still won't fire. TSS usually only causes issues when engaging throttle or if cable is too loose. The timing sensor probably got whacked when changing out the stator. I have seen so many stators changed on these for no reason other than "it has to be stator" and still same issue. Lots of good used ones in garbage cans out there. Same goes for ECUs, but much easier to swap out. 90% of electrical issues on these sleds is harness/connector problems. M Series were same and worse due to poor routing (under gas tank, taillight harness, ground attached to post support).
 
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