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XM summit - RPMs won't climb when stuck in deep snow

4K views 18 replies 6 participants last post by  Dynamo^Joe 
#1 · (Edited by Moderator)
So last year I've been chasing an issue that I didn't have the previous years with my '13 summit X 154 2.5". Whenever I get stuck in deep (or wet) snow, the engine loses rpm all the way to roughly 6500 rpm. Once stuck, if I nail it again, it won't climb above that. It is getting very frustrating and makes it hard to get unstuck!

Throttle response is also not very crisp, I always have a 1-2 seconds of delay before the engine revs to 8000 in normal conditions, which makes it a bit tricky to ride around trees always trying to compensate for that 1-2 secs.

Current clutch setup is the following with 21/49 gearing at sea level:

160/380 or 160/350 primary spring (will open it to check it out)

441 ramps

pin weight adjusted for 7900/8000 rpm

Stock 40* helix

Black 157/303 spring

I was thinking of switching the secondary spring back to the stock blue spring, but I was thinking this would probably only make the problem worse.

Maybe it's something else than clutching? All help is appreciated!
 
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#3 · (Edited by Moderator)
Clutches are cleaned every season.

I've also replaced both clutch springs last year following that issue. O-rings are new and every bushings/rollers are in spec according to Doo service manual.

Compression is 145 on each cylinder.

I've read of possible issues with fuel regulator being loose so I've taken a look a it but it looks fine. All 3 fuel filters replaced. I'm about to pull the trigger on a new regulator and fuel pump, but was looking for advices on here first just in case...
 
#4 ·
What track length? You're geared too high unless maybe you are under 170# and it's a 146. I would run a 19T top gear. I don't think that's all your issue though. I had a similar issue where I would make rpm on hard pack but not in powder and it was because my aftermarket spring cup had a chunk come off and was limiting primary movement. The black spring should aid in backshift which should actually be helping. The lazy throttle response does it bog or does it stutter like it's hitting the rpm rate of increase limiter? Have you cleaned raves?
 
#5 · (Edited by Moderator)
It's a 154 2.5" and I weight 150. The gearing is actually the OEM configuration for sea level. Should I switch to 19T?

Throttle response is more like bogging a little before revving all the way to 8000 when not in too deep stuff.

My clutch assembly is quite old at around 8000 miles even though if I've replaced all components around 2000 miles ago. Perhaps, something's wrong with it. I will reinspect it because the behavior you described ressembles what is happening with mine now.
 
#6 · (Edited by Moderator)
So last year I've been chasing an issue that I didn't have the previous years with my '13 summit X. Whenever I get stuck in deep (or wet) snow, the engine loses rpm all the way to roughly 6500 rpm. Once stuck, if I nail it again, it won't climb above that. It is getting very frustrating and makes it hard to get unstuck!

Throttle response is also not very crisp, I always have a 1-2 seconds of delay before the engine revs to 8000 in normal conditions, which makes it a bit tricky to ride around trees always trying to compensate for that 1-2 secs.

Current clutch setup is the following with 21/49 gearing:

160/380 PL/PK primary spring
441 ramps
pin weight adjusted for 7900/8000 rpm

Stock 40* helix
Black 157/303 spring

I was thinking of switching the secondary spring back to the stock blue spring, but I was thinking this would probably only make the problem worse.

Maybe it's something else than clutching? All help is appreciated!
If a new problem develops long after any parts have been changed/added then the problem is most likely maintenance related. Although clicker position could be creating part of your issue.

Check:

All movable clutch components (including bushings)for excessive wear and binding. OEM rollers in the secondary have a reputation for exploding (can see them through the helix) hi-tech rollers out of BC are the only rollers I use.

Reeds, OEM tend to be the most reliable, but even they fail.

Sparkplugs, leads, anything that could cause a weak spark.
Sparkplugs need to be indexed on etec engines. Ground strap must not be between the spark and injector

It could also be fuel related.
Pump could be worn out (automotive pump can be used to save $$$, same pump different source)
Regulator could be faulty or have some trash stuck in it. The housing can also be faulty allowing the regulator to be pushed past it's retainer. There is a recall for this, it's basically a band around the regulator with "wishers" incorporated into the top and bottom. It holds the regulator down and prevents the housing from deforming.

Raves. Sticky or malfunctioning raves can definitely cause bogging and throttle response issues

Compression. Easy to check while you're there. Should be 140+psi, within 10psi of eachother. Throttle wide open, gauge reset before each cylinder.

These would be the first things I'd check and as I said at the beginning if the problem developed long after and changes then it's most likely a maintenance issue and not a clutch tuning issue. That's like changing a wiring harness before checking the fuse.

Sent from my Pixel 2 using Tapatalk
 
#7 ·
It's a 154 and I weight 150. The gearing is actually the OEM configuration for sea level. Should I switch to 19T?

Throttle response is more like bogging a little before revving all the way to 8000 when not in too deep stuff.

My clutch assembly is quite old at around 8000 miles even though if I've replaced all components around 2000 miles ago. Perhaps, something's wrong with it. I will reinspect it because the behavior you described ressembles what is happening with mine now.
Are you at sea level or in the mountains?
 
#10 · (Edited by Moderator)
Aaen Pg 24. The higher the spring load, the more RPM or heavier weights are needed to overcome it. Spring force can be used to influence the "shift curve" and obtain a desirable "straight shift"

IF the engine speed is drifting low (below its power peak) THEN the spring force is not providing a "straight shift".

Ok, the spring chart has color coded spring lines to show the 3 springs mentioned above.

IF you're losing engine speed (its drifting low) THEN at-that-track speed (example 70kmh(42mph)) the spring force being used at-that-track speed is too low.

Aaen Pg 24. The higher the spring load, the more RPM........are needed to overcome it. Then a higher spring force at that problem track speed should make a more "straight shift", either lose less engine speed or not lose engine speed.

If you went to the blue spring, you'd lose engine speed earlier in the track speed.

The blue line is off 10 pounds too high on the end force, should be 220, not 230, but im not going to make another picture...

Rectangle Slope Triangle Font Parallel
 

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#11 · (Edited by Moderator)
Black 160/303

Blue 160/230 (this will make it worse and lose engine speed earlier...haha)

Purple 231/303 BRP#417127062....<<< go to this one Buddy.
Purple spring with 40* helix? Won't this make the primary pull on the belt a bit too much with a spring that stiff? I actually think I read that somewhere on your website :lol:
 
#12 · (Edited by Moderator)
Purple spring with 40* helix? Won't this make the primary pull on the belt a bit too much with a spring that stiff? I actually think I read that somewhere on your website :lol:
Okydoky then....

Green 180/303

Dalton red 200/305

Dalton red/yellow 218/305
 
#13 · (Edited by Moderator)
Seeing that In normal conditions there is always a delay of 1-2 seconds before the engine revs to 8000 rpm, that sounds so much like fuel pressure. And it is worse when it gets gets stuck, so again it sounds like fuel pressure. I can't think of anything else that could remotely cause this, but it should show on a stand with a fuel pressure gauge and multiple on/off full throttle.

When hitting the throttle and the power lags behind for a second every time and in all conditions, there isn't anything that I can think of that can do this. The CVT is the component that can make a problem appear like a lack of fuel, but once you get used to both scenarios they are not the same. For example a weak secondary spring will overshift and loose power, but the power won't magically recover like nothing happened, nor will it recover each and every time like it is being described with normal conditions, which I assume is the trail portion of the ride.

A poor running fuel pump will take time to build enough pressure on demand. After a brief moment the fuel pressure will build and that's when the engine kicks in. When the demand is high and constant, the rpm will drop due to lack of power. Of course this is only one particular type of fuel pump issue, but it can be seen when riding with either a fuel pressure gauge or Wideband. The pressure will drop 10 or so psi, and the wideband will show lean and off the scale, and then recover but with a pressure that is at least several psi lower than spec@44 psi.

If you take the time to describe the problem further with different scenarios, it will become clear. Either way the fuel pressure gauge is the first tool for diagnosing this type of problem. It is inexpensive to buy and easy to build a setup for the E-TEC. On a stand you won't see the pressure drop like it would while riding, but it will drop a few psi on a stand. The work will also be a lot easier than fiddling with the clutches.

If you decide to bring it to a BRP dealer, an experienced tech should be able to see this problem, especially if they compare with another E-TEC. Feel free to copy this reply and see what they think. But the price tag will be much higher.
 
#14 ·
This reminds me of a project I once tried to undertake, a cheat sheet for power loss. I still remember the first time that I looked at Dynamo^Joe's web site with details on power loss for the SDI. I though it was brilliant, and it became obvious why he would focus on power loss. If the engine wasn't performing, the first suspect was always the clutching which would drive me nuts knowing the clutch kit worked. This was back in 2012. It took several years before I got a better grasp of why he was having so much trouble with the Renegade 1K SDI. Fast forward another several years and he installed a wideband on his E-TEC. The Wideband shows fuel delivery problems immediately. But what do you do if you don't have a Wideband?

Once you know how a sled reacts when there is an electrical issue and the engine cuts-out completely like hitting the kill switch, or an eRAVE issue like the exhaust valves drop which causes an obvious drop in the engine tone, or a full fuel delivery cut-out like when the fuel sump empties and does not recover until letting go of the throttle, or a momentary loss of power in transient loads when the fuel pump has trouble keeping up, then it becomes so much easier to diagnose on the trail.

An electrical cut-out and fuel cut-out both suffer a major power loss, but they are not the same. Suffice to hit the kill switch for a comparison. It would need a very specific and rare electrical issue to mimic a fuel cut-out, and even then the electrical issue such as a loose ground or intermittent stator would show-up as sporadic compared to a fuel cut-out that can be repeated on demand.

An exhaust valve issue is also different as it will either drop the valve and show an audible low tone change that is remarkable, or a constant movement of the valves that shows up as a constant on/off of full power with intervals of a second or so. It may sound familiar to a fuel pressure recovery of a second or so, but this particular fuel pressure issue will not cycle like this exhaust valve issue.

I guess that I did finally complete the project. I only gave 5 scenarios including one for the CVT. Obviously there are more, but these are the common ones that I focus one.

The key is in how the power is recovered.
 
#15 · (Edited by Moderator)
Daag, Joe,

Thanks for your detailed answers.

Regarding clutching, I'm definately going to test with purple/purple spring back to back with blue & black so I can get a feel of the different springs on the QRS! Tonight I dissasembled it and the rollers inner diameter were near the service limit according to doo manual which is 8.5mm. One was around 8.33mm and the other around 8.47mm. Anyone know what is the diameter of a new piece?

I also checked the primary and all buttons are below service limit of 7.95mm at around 7.88-7.91mm. I'm not sure though if that would have any impact seeing the service limit for a 600etec is lower at 7.45mm.

I'm basically going to go through all the stuff you guys suggested. I'm going to measure all bushings of both clutches and put new springs in.

I have already ordered new fuel filter as well as pump strainer...Will try to test the fuel pump pressure as well. I actually found a post (but can't find it again) of either daag or joe that posted videos of or '15 or '16 800 etec with a fuel pump pressure test at idle. One was at 42psi and once the pump was replaced it was at 45psi...

Now that I'm thinking about it, my '13 800 etec never started well, especially when really cold out. It ALWAYS starts, but dies right away and feel like running on a single cylinder. Then I hit the starter another time and it will keeping running roughly until I give it some throttle and then it clears up and runs fine the rest of the day. I always thought it was an ECU software issue though...
 
#17 ·
Bitter sweet. The cost for an OEM pump is steep. You could get an aftermarket one or one from a part-out, whichever fits the budget. I would also question the fuel filter. It is only sold as an assembly, but I can find the oem part number from the Can-Am side, or the WIX part number that can be bought at any auto parts store.

The CVT rebuild was a good move.
 
#18 ·
[Now that I'm thinking about it, my '13 800 etec never started well, especially when really cold out. It ALWAYS starts, but dies right away and feel like running on a single cylinder. Then I hit the starter another time and it will keeping running roughly until I give it some throttle and then it clears up and runs fine the rest of the day. I always thought it was an ECU software issue though...]

Now that the 30 psi is known, what you explained above makes a lot a sense. I assume the pressure was low from the start, definitely higher than 30 and likely in the low 40s like the case you read about.

There is one thing that I find ultimately remarkable, which is how long this engine survived with inadequate fuel pressure. The amount of tolerance with this engine is unreal.
 
#19 · (Edited by Moderator)
Regarding clutching, I'm definately going to test with purple/purple spring back to back with blue & black so I can get a feel of the different springs on the QRS! Tonight I dissasembled it and the rollers inner diameter were near the service limit according to doo manual which is 8.5mm. One was around 8.33mm and the other around 8.47mm. Anyone know what is the diameter of a new piece?

Now that I'm thinking about it, my '13 800 etec never started well, especially when really cold out. It ALWAYS starts, but dies right away and feel like running on a single cylinder. Then I hit the starter another time and it will keeping running roughly until I give it some throttle and then it clears up and runs fine the rest of the day. I always thought it was an ECU software issue though...
Poissonn, i can't see what he posts, content is blocked. please dont lump him in with me, thanks.

You might have seen posts of mine and i put videos on to show personal firsthand knowledge of performing fuel regulator and pump pressure checks. ive done a few over the years and latest one was at the end of last season

I take a look at the engine power by the clutches. the clutch settings are a mirror of engine torque. I'll shock the system with a spring (Aaen: springs are rpm sensitive) like striking a tuning fork, i'll hit the engine power with a spring that should change engine speed. You change to that spring and it should clearly demonstrate the engine power shape in a visual way. IF the conduct of the engine does not change much or does not change in a certain track speed or pull that you do regularly, then I would be looking back at the engine power, management. Exhaust, fuel..and if can't solve there, then have to go deeper into the layers of onion.

Logic statement: IF the purple 231/303 secondary spring still reveal the same engine speed drift, THEN something else wrong; and i would have said "change the can (if there is one) to the stock muffler" and re-test. And next would be check the fuel system. I dint say anything about bushings because when you pull the clutches apart, there's a high probability of visual inspection anyway and cleaning, measuring almost a moot point, you're visually inspecting as you change the spring(s), and there's enough spring force change to cause an engine speed fluctuation....so, measuring bushings at this point, meh... :mellow:

...and now i bet you go run with new fuel pump, you'll prove my point.

So my post on spring change was on 2 prongs of knowledge. Prong 1) I know what a 231/xxx should do to change the behavior of how the sled runs (which is why i suggested to apply). Prong 2 is IF the behavior was modified in one certain area "that you would report on", but not in "the pull", THEN i would conclude there's an engine power management problem; and start to go through that checklist.

Happy highmarking
 
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