Ok smart guys......?

[MN Mike]

Got something to run past you, my Mtn Cat 900 EFI is 'acting funny' how that for technical

Changed spark plugs with brand new ones, sled has 840 miles or so on it.

Get out on the lake, bring it up to 30 or so, no problem, acceleration and crusing, runs fine.

Bring it up to 50 - 60, acceleration is no problem, back it off to cruise, it looses a cylinder, grab the throttle and it might act up for a moment, lights the other cylinder and away we go, no problem as fast as you want to take it, both cylinders are hitting just fine, just can't bring it down to cruise, it looses one of the cylinders. I'm not sure which one it is. Plugs look nice, both have the same shade of cookie brown.

I'm thinking either I have a injector going bad, maybe a coil( but I don't think so ), possibly a bushing in the throttle need replacing or maybe a bigger problem looms

Anyone have such a problem on thier EFI ?

Mike

[jstirewalt]

MN Mike:

Have two possible ideas, one is that the kill switch is going bad. Cat has had a lot of problems with these - easy to bypass. In fact, alot of the supplied tool kits on the older sleds had the bypass wire included. It should unplug between the throttle and where the wire runs into the hood. The other idea is throttle cable tension. There is a safety switch located in the trottle bodies that senses throttle position and has a shut off. Maybe one cable is misadjusted?

Just some ideas.

Jeff

[Eyewitness]

Mike, does your sled have an ECM (Electronic Control Module)? If so, they are very finicky about having proper voltage to them and can do all sorts of weird stuff. My newer SkiDoo was having similar problems, even some back firing. Found out that the ECM can be an issue and once I addressed it my sled actually runs better than I can remember now. Apparently the plug in connectors if not maintained, can cause just enough oxidation to play games with the voltage causing problems. This is due to the dialectric grease drying up and thus allowing this to happen.

Go to the local auto store and pick up a small spray can of dialectic cleaner/dryer (about $4-5) and a small tube of dialectric grease. Unplug your connectors from the ECM and spray them out thouroghly with the cleaner/dryer. Blow them out by mouth or with compressed air (preferred), and let them dry completely for about an hour. Then fill plugs completely with new dialectric grease and plug in. That's all there is to it. About 15 minutes worth of work and $5.00.

Because of the lack of snow many machines have not been used very much in the last few years and just because they have less use doesn't mean that this can't happen.

This may or may not be your problem, however from the folks at the dealers I've spoke with it seems to be a common problem with the newer high tech computerized sleds.

Hope this helps. If not, maybe someone else will be hlped by reading this.

Good Luck!

[MN Mike]

Good points guys, looks like I'll have some snow to go and do some trouble shooting.

I'm hoping that if it is an electrical problem it's something easy like you guys suggested, I've been on those wild goose chases, turned out to be the exciter coil, that took 2 weeks to find that problem.

I'll let you know if I find out for sure what it is.

Thanks

Mike

[MN Mike]

Well, I might have gotten lucky, run 1 bottle of injector cleaner thru it and everything seems fine. Must have been some gunk in the injector somewhere.

Did a compression test and both cylinders were about the same so that was a relief.

Mike