Running poorly, but no codes

right on, yup I ride with a bunch of 163's so my 151 x 2.4 leaves a little to be desired in the fluff. If I'm still riding the 9 next year I'll step up to a 166

94fordguy said:

The 166 does seem to hook-up very well.... absolutely no complaints with mine. Definitely nice for those bottomless days

Click to expand...

Series IV's are dirt cheap too! Yeeehawwww budget climber, but that's not for this season lol.

Just got home from a wicked 2 day trip, bottomless thick heavy pow in the loose trees and gently sloped pastures... the odd hillclimb. Avy conditions were bad so we stayed out of the high alpine and complex terrain. Today was probably the single most fun day I have had on a snowmobile!

Anyways, my run-ability issues have returned... but slightly different.
From 1/3 throttle and up, or with any sort of load on the track it ran awesome. Pulled hard all weekend between 7400 and 7650 depending on elevation. Great response, normal fuel economy, normal oil consumption, plugs are a bit rich looking compared to normal.

Idle is my biggest problem: After run time when stopping, the idle hangs at about 2000 and sounding like only 1 cylinder. Most of the time, after a moment it comes down to about 1300 or so and at this point it sounds like 1 cylinder is mis-firing sporadically... other times the idle remains at about 2000. Start up gives me the 1300 rough idle.

Off-idle to 1/4 throttle have a little bit of sputtering, hardly noticeable.

Coming out of WOT, if I ease off to about 1/4 and hold.... I occasionally find a flat spot... just sounds a little flat and sick. If I quickly go back to WOT from here it sometimes hangs at that RPM (about 6000) until I made another throttle correction. At any time during this if I make a small correction to the throttle it immediately comes back to life. This does not happen often at all, but is there.... sounds alot like the 5000 - 6000 rpm bog issue posted about frequently. This has happened in the past but rarely, starting to become less rare now.

I had adjusted my idle recently so it is probably not at .930 on the TPS anymore, I will re-test and set the TPS / idle when I get started on it.
Any thought on this? I'm expecting more wiring issues or a sensor glitch. Whats got me scratching my head is that it runs excellent at mid-to-high rpm, and what the hell would make it run on one cyl like it does at low rpm / less than 1/4 throttle.
Frustrating stuff at times this EFI stuff lol. So far my plan is to re-test / check all sensors, coils, reeds.. the usual. I made sure to get helmet cam footage / audio of these problems in action, I'll hack together a clip and post it here within the next few days. Back to work tomorrow night, this was my fifth weekend in a row out on a BC mountain trip, loving life!

I should have mentioned that I put new, and properly gapped plugs in during the trip... no change,

I could be wrong, but I don't think that's the case here, I put in some antifreeze, have run about 4 tanks through the sled and the problems are always there, cold or hot.

05900 said:

Ck throttle block assy?? Two switches in it and timing is everything you should see it worn as an OVAL hole with lots of slop threw my cable adj off also!??
Exhaust temp sensor only showed on Digital Wrench it stuck at 385 and never moved!
Dealer found it....

Click to expand...

Safety switches in my throttle block seem to be ok, no change when I un-plug them.

Anyways, here's a quick clip showing the idle problem, and yes I had just been dis-mounted from my sled lol.... good opportunity to hear the idle:
http://www.youtube.com/watch?v=ygEYp_NTJ90

I just hit precious days off!
I retrieved my defrosted sled from a friends storage building and got it to my shop so I can work on it. Hopefully I can find a problem tomorrow... updates to come..................... for now it's time to recover from night shifts zzzzzzzzzz

Anyone care to comment on the video? Idea's?

The more I think about this... the more I think I have an air leak or something. It acted sorta the same when I had a chipped reed pedal.
Also when my throttle body pulled out of the boots (air leak on the engine side of the TB's) it idled bad like this.
I guess I'll start with some spray to check for air leaks in the morning. I need to re-set idle voltage as well since I had been adjusting idle out in the mountains.

I have bigger concerns now, started looking around today and found my front engine mount x-member cracked by the mag side mount.
Started pulling the engine.... clutch came apart in 2 chunks... nasty lol.
My 900 has the mid-season blues

I got my puller in hand tight, got a bar on the end of the puller, and within a 1/4 turn it just came apart.

Yes Sean I have Compfusion mounts, the crack goes right through the mag side puck.

Yup, I agree Seth, nasty sounding at idle... but runs great as soon as you apply any throttle. Plugs are wet-ish. She'll be coming right apart now anyways, a good chance to really check things over.

Ok I am in a PM conversation with Franz (Jeff) about a billet x-member as we speak. That would be problem #1's solution.

The clutch, well I do have a spare inner sheave, so its possible to have someone build a clutch for me with the parts I have. You may have seen my post about purchasing a spare parts sled... if that clutch is good I could finish the season with it.... have to see how the deal on the sled works out next week.

The idle problem... have to have a good look at the motor when its apart. If it's mechanical I will catch it then, if not... I think I'll be installing my known good stator and swapping more wiring and sensors.