06 M7 Issue's

[Thaddeus]

Hey all, new to the forums. site looks great! hoping to get a bit more help here then arcticchat!

I purchased a 2006 m7 153 efi last year and started to notice a few things with it. first, anytime its below -15 it does not like to start. wich is kind of embarrasing being a snowmobile and all haha.

anyway,once running it gets the usual bog around 7000rpms, if i keep it pinned and really ride it hard it will pick up and seem to be good for a little while. ive checked my brake light wiring, its good.I have checked my plugs, they seem to be ok. i have cleaned my power valves ( have not adjusted cables, cant find any info on how to do that) my compression is 127psi on both cylinders so i know thats good.( known good compression tester)

On my last ride this year it really acted up on me. it started popping and bogging right out, loosing all power. if i feather the throttle it will eventually pick up but with about 1/4 of the power.it seems to idle ok, but after idleing for a minute or so it dies out. im hoping for the best but in my head im expecting the worst.

Just wondering if anyone has had similar issues or things for me to check out. when checking plugs my clutch side plug looks to be burning perfectly. however my (brake?) side plug was fairly wet. i know these sleds are kind of known to over fuel. wich i think may be my issue. sled has a y pipe, d&d main pipe and mbrp can.( i dont have any old exhaust parts to try stock ones.) however because this used to be an intermittant issue i dont believe its related to the exhaust components. I should also add that i do not get a check engine light/flash code.

I used to run the 91 octane till i found out that the sled wants 87. i put 87 in it and when it was running good it seemed to run better but i dont think its my issue. seems damn near every m7 out there has this issue. im kind of glad that it got this bad, will help make diagnosis a bit easier. just went to try and get a video of it running, and the puull cord snapped, not a good. day
I have pulled the exhaust off and the plugs, got a good look at the pistons/cylinder walls and all looks good still.i tried checking for spark( had to rig up my own rope and tie it to the handle) and I am not seeing any spark from my plugs, all though i don't think I am getting as good of a pull with my rigging job. i did notice that the cylinder closest to the brake has oil/fuel in the y pipe and the clutch side did not. even though compression is equal. can a coil pack fail on one cylinder? any help would be greatly appreciated. do snowmobiles have some sort of maf/map? because on the brake side intake the boot for the throttle body was half off and in the way of the throttle body.
just to get as much info in this thread as i can for this issue for other people looking in the future

similar issues people have resolved with
- wiring harness to rear brake light, shorting. causing spike in amperage and the ecu kills spark(i believe)
- wiring harness to diamond drive housing does similar thing.
-bad ground near coolant resivour and steering post.
- wires rubbed through on steering post from being zip tied to tightly.
- bad spark plug wires.
-bad wiring underneath gas tank.
- replacing complete wiring harness seems to fix it for most people.
- some say they run very rich, fuel pressure needs to be checked. boon docker box's help lean it out a bit. or a fpr.


After ripping the sled apart, I cant find any obvious frayed/broken wires. i have found some corroded/half plugged in connectors going to my handlebars that i will be cleaning up and re installing, i don't think this is related though. but the previous owner of this sled managed to break the housing on the ecu. and i noticed this on the ecu today, just wondering if it could have an effect? and it is slightly dented as well

Anyway, thanks for reading! I know there is a lot there but I appreciate any help anyone can give!

 

[drosichu]

Clutching! Take a look at your weights, clutch for elevation. Replace primary spring and check out your secondary rollers/spring. I had this same issue on my 7 and mine turned out to have the stock mountain weights in the primary and I was riding it on the flatland.

 

[jaredszakacs]

chitty deal thad now I know your name on here and I can harrass you!!! you should be alright on the pipe side of things mine had pipes and airbox timing key ported heads and jugs and ddint need the fuel controller m7's run really rich to begin with kind of like my etec. has the sled done this before? maybe its doo time

 

[Thaddeus]

Just curious,how clutching will make,my engine bog completley out all of a sudden. Im not saying thats worong im just wondering how it would do it. Especially because it used to be intermittant. SosomEtimes the sled worked great. Anyway im in the mountains and its clutched for mountains. I have a white and orange spring but thats all I know about that. Thanks for the info. Jared get outa my life haha. The day I buy a doo is the day I give up on life.

 

[leadfoot33]

you would be very surprised what clutching can do. make sure belt is adjusted correctly in the secondary check all the weights and rollers inthe primary. spider could be hanging up my M7 had to get the spider replaced as it was cracking and hanging up a bit. also check your airbox at the front make sure its not full of snow

 

[Thaddeus]

ok ill be sure to check all this out. im only curious because the engine is bogging before the clutches engage.
Thanks for the help!

 

[moyiesledhead]

Check/replace your reeds. Would also be nice if you could find a stock exhaust to try on it. Most of the M7's hated pretty much all after market exhaust...I've tried most of 'em and always went back to stock. Stay with the 87 octane fuel too, unless you do some mods ie: a head. They really don't like 91 when they're stock.

 

[Thaddeus]

ill be checking the reeds out soon as possible. i pulled the wiring harness right out just to clean up all my connections and test each wire for continuity/high resistance. once i get that back in ill put the sled back together and run through a few other tests. I have been told this could be caused by a bad oil pump, because when they fail they fail to full oil. any more information on that? i dont know if that could be my cause. i havent noticed excess oil from my exhaust and i dont seem to be going through to much oil.

 

[leadfoot33]

i am not 100% on the oil pump thingy but it is definetly possible but you would notice excessive oil consumption and maybe fouling plugs. my sled when i had it did sputter when i ran 91 ( was all stock except jaws can) but i rode it hard and it cleared up and wouldnt bug me once i got going.

 

[Thaddeus]

well just for anyone with this future problem. i havent confirmed a fix yet. but after reading up on how many people fixed this issue by replacing the main wiring harness. i decided to pull the harness out and to pin fit checks and continuity checks through every wire. i found that my fuel pump wires at time had an extremley high resistance almost to the point of an open. i cleaned up the terminal ends and got it down to .3 of an ohm. So if your having this problem. save yourself alot of time. pull off the connection to the fuel pump and ecu. run a ohm meter from one end to the other. solid red and solid black wire on the ecu. I will post weather or not this fixes my issue or not. but either way im sure it will help.

 

[usher]

Check your power valves.... Clean them and check cable length

 

[Bails]

Ya I'm with Usher, I had an M7, and the power valves seemed to gum up easily . Clean once a year as regular maintenance and check cable adjustment. Makes a big difference.

 

[SIRsleeper]

Old thread but how did you fix this? I'm "flooding" the same cylinder, EGT's are way off and there's loads of oily mess in that pipe (I'm running twins)... I got to ride my sled once before this started and it's a real bummer


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[mighty1000]

Are you running a fuel controller at all? I had my m1000 when I put a pipe kit on it and setup with a controller to be running way to rich in the mid range and it did the same thing it would send one cylinder almost dead cold on the EGTs compared to the other side. All I did was started pulling fuel away and that cleaned it up. Hope this helps

 

[Jimbara]

mine did this a couple years ago and it was the power valve cable coming off of the servo. there is an 8 dollar update clip that holds the cables from coming out of the pully.

 

[8675-30-9]

Mine had the same issue when starting out. A dead spot when I blipped the throttle. Pulled the power valves and walla! a small gap was noticed as they were not sealing all the way closed. . Replaced them now runs like a champ.

Check your power valves.... Clean them and check cable length

 

[nathan#19]

I would be looking at the reeds right off the bat. They can do the strangest intermittent stuff and ruin a few days before getting found.