Can't get above 6,000rpm

ssearle · Feb 18, 2011

still not working

I re-set baseline and tps. The sled still won't idle unless I hold the throttle a little and still won't go into reverse but if I feathered the throttle at almost wide open it shot up to 8,500-9,000 rpm. I thought that problem was fixed. I let the rpm's come back down and shot it back up a couple times to that high rpm. Then on letting it come back down again, it stalled. I started it back up but now it's back to only going to 6,000 max rpm. I adjusted tps from .93 to .95 and it kept bursting up to 8,500 rpm with finding the sweet spot on the throttle at the high end but wouldn't maintain. Now I'm back to not being able to get it above 6,000 rpm.

If something was triggering the DET to do this, the check engine light would be flashing, right? If the DET advances the timing, doesn't it cause the light to blink?

Oh yea, and the only way to get the sled to idle on it's own is to unplug the tps sensor. I checked voltage in the tps plug while it was idleing and unpluged from sensor, I was getting 4.95 volts going from wiring going to sensor. Is that okay, I was thinking that was supposed to be 5 volts.

ssearle · Feb 18, 2011

more info.

I swapped throttle body/tps sensor and reed assembly from other sled. No change in how it runs. Won't go above 6K rpm. Adjusted throttle cable in line near steering to get idle up. Idle good, still no reverse.

Anyone???

ssearle · Feb 18, 2011

little change

Rpm surges up to 9,000 every now and then (3 seperate times today while tinkering).

Z-Man · Feb 18, 2011

checked for vacuum leaks?

Z-Man · Feb 18, 2011

Also assuming you swapped the coils from the other sled too? Something you might do just to eliminate a bad ground is wire in a ground wire from were your body ground is by the clutch to a bolt on the engine.

Danbot · Feb 18, 2011

9000??!! dude you gotta watch it revving your engine that high lol.... are you running it with no belt on?

TriumphoverU · Feb 18, 2011

It almost sounds like a timing issue to me, whether it is a fuel timing or ignition timing issue is irrelevent. Check for a sheared flywheel key, or to see if the ring has spun on the flywheel. I'd swap flywheels and stators from the known good sled to see what you've got.

ssearle · Feb 18, 2011

Lots of good info.

I did swap coils.

I swapped bellows and power valves, pulled springs and plugged lines. Is there anything else I should do to check for vacuum leaks?

I will run the extra ground wire. Good idea...

I am running it with the belt on and the back end lifted.

I did swap stators. The flywheel and key looked solid and good. I'm not sure what the ring is that can spin around on the flywheel. I will take it apart tomorrow and see if I can figure that out and make sure it's intact.

It does seem to me like the timing is just a hair off too. If this were a car, I would rotate the (what is it called, coil) a little and I'm sure, it would fix the problem. It acts like it's just not firing at the exact right moment.

It also seems like it's a voltage thing because when it does shoot up in rpms, I'm feathering the throttle in the mid to WOT and then it act's like it finds the sweet spot and just takes off. When this doesn't happen it keeps spitting from 6,000-6,300 like it's going to, and wants to, take off but doesn't. But I've swapped everything electric.

It's weird that reverse still doesn't work, idle is low (without adjusting cable) and no high rpms (except the intermittent tease). It's like something is giving the engine false info. on rpms and when to fire. But again, all swapped. GRRRR!

Z-Man · Feb 19, 2011

wow, you have just about done everything you can possibly do. Did you drain your gas tank and put fresh gas in it?

Carb cleaner carefully sprayed will cause the engine to bog if it finds a vaccuum leak. I use a small bernz-o-matic propane bottle with a rubber hose on it. carefully aiming the hose around the engine with the gas sligthly on will cause the engine to rev if there is a vaccuum leak.

Ok, just reread the entire thread on this. Did you recheck the compression ever? If it is 100 it is never going to run right. Got another sled to swap parts, then swap the whole fuel tank and see if it runs and the other still runs. Lots of people commenting on bad pistons causing something like this, I am assuming you took a good look at them through the reed ports when you changed the reeds. A sled with one bad piston with bad compression will also act exactly like what you are describing.

I don't live in CO but I mapped out your location and I will be coming there end of March. I have to pick up a sled in Denver that I am buying. If you still haven't got it running by then I might have to loan you a sled for a day and head to the mountains.

TriumphoverU · Feb 19, 2011

I know you said you swapped out all electrical components, but did you swap out the crank position sensors too? There is a 5 tooth sensor and a 2 tooth sensor, sounds like you may have an issue with the 5 tooth sensor. If you have the 2005 deep snow manual check out page 13.28 to see what I'm talking about.

if you do not have the 2005 manual, get it here http://chadt.us/manuals/index.php?option=com_docman&task=cat_view&gid=36&Itemid=57

I'd still try swapping flywheels between the two sleds, as a couple degrees could make a big difference in timing and may not be noticeable just by looking at the flywheel.

Z-Man · Feb 19, 2011

here

Z-Man · Feb 19, 2011

Timing

TriumphoverU · Feb 19, 2011

Here is what the manual says regarding the CPS

When the sensor is inoperative or disconnected the system will switch to a "LIMP HOME" mode. Limp Home mode reduces performance to a default value and monitors other sensors.

The 5 tooth crank position sensor (A) picks up all 5 flywheel teeth (C).

The 2 tooth crank position sensor (B) picks up 2 off set flywheel teeth (D).

Both crank position sensors will have a gap (E) to the flywheel pick up of .035" (.90mm).

These sensors must be in the correct position or the engine will not run as expected. A sheared flywheel key will cause the enging to not start or kill if running.

The 2 tooth pick up detects the crank angle and obtains minimal information of the crank angle when control enters into limp home mode.

5 tooth pickup is to obtain the following information in combination with the 2 tooth pickup.

- Judge direction of rotation (forward and backward)
- Ignition advance angle control
- Injector drive angle control
- Excess advance ignition control at reverse

TriumphoverU · Feb 19, 2011

You beat me to it Z-man, had to type it all in manually, the copy of the manual I have doesnt allow me to copy pages from it.

Yes that page is what I'm referring to. Make sure the wires havent been crossed somehow on the CPS's.

Z-Man · Feb 19, 2011

TriumphoverU said:
You beat me to it Z-man, had to type it all in manually, the copy of the manual I have doesnt allow me to copy pages from it.

Yes that page is what I'm referring to. Make sure the wires havent been crossed somehow on the CPS's.

I have the same copy...lol. hit cntr and print screen. then paste it into a photo editor and save it as a jpg file.lol

Z-Man · Feb 19, 2011

If you just swapped parts and did not time it afterwards that could be a problem for sure.

ssearle · Feb 19, 2011

You guys are awesome

The dealers are just shrugging their shoulders saying "got me". You guys keep just keep coming up with more great ideas.

I will do a compression test myself. I can't find dealers results, they just said "it was good" whatever that is.

I'm not sure about that sensor. I will have to look it up and see if it's one I changed over. If not, I will do that right away.

I'll do everything you guys suggested and get back with the results. May take me a few days. We're taking our other sleds and heading for the Mountains. Wish me luck. Talk soon.

For sure, when you come to Colorado, I'll grab one of my other sleds and we can hit some good stuff.

ssearle · Feb 20, 2011

more info.

Okay, to answer some questions...

I did drain fuel and start with fresh. I did eventually swap fuel tanks.

I will try the propane trick to look for a vacuum leak. Good idea...

The pistons looked good from what I could see but I did notice that it seemed like on the bad sled there was more fuel/oil residue coming out of the reed assembly area. Good sled was much cleaner looking and didn't have oil all over the front of the sled. Don't know if this means anything?

I did swap both sensors when I swapped the stator. I haven't swapped the flywheel yet but will try that. The key was intact when I swapped stators. As near as I could tell, the sensors couldn't be mis-matched very easily because of wire lengths and it didn't seem like you could adjust the sensors. If you can't adjust the sensors and you can't adjust the flywheel because of the key, how do you change the timing? I see how you can check it, which is one of the things the dealer did and he said it was good. With the info. you guys provided I may need to go buy a timing light and re-check the timing to see if it's barely within acceptable limits or dead center, or what.

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Can't get above 6,000rpm

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