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Boost won’t rev past 6500??

mt.sledder

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Nov 28, 2007
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Saskatchewan
My boost has been experiencing issues. Sled has 1700 miles on it and has runs ok up till now. It started with moderate dets. They would occur when you punched the throttle when moving along at about 30 mph. It has now gotten to the point that it seems to be in a permanent limp mode. Took it to the dealer and Polaris told them to replace the det sensor. That got done and I took it out for a rip, no det codes have come up at all. Sometimes at startup I only get 850 rpm for an idle and have to work the throttle to get it to stay running. Will clean up some around 3000 rpm but let off and back to 850 and won’t run on its own. Shut it off and restart and same thing, only idle at 850 and quit. With a few start/stop sequences every once in a while it will idle normal at 2000 rpm. Go for a drive and the sled won’t rev past 6500 rpm like the exhaust valves are closed and won’t open. Prior to the first visit to the dealer I have gotten a cold primary injector code. This is definitely not a fuel quality issue. Fresh non ethanol premium. I bumped up the octane by mixing 50/50 av gas and the issue continued. Sled is all stock with the exception of a P85 clutch and a silicone 90 on the turbo intake. I’m having trouble attaching a video.
 

idahoskiguy

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Feb 17, 2008
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Boise, ID
Wow, that is not good, hope your dealer gets this figured out. You may be on the right track suspecting the exhaust valves. Have you looked at the reeds? Reeds that are not sealing could cause the behavior you have described.

Good luck and report back.
 

madmax

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Put in a throttle safety switch bypass. If that doesn’t fix it, it will at least save you headaches in the future. They are cheap.
Is there a check engine light on? What codes come up on your 7S?

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mt.sledder

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Nov 28, 2007
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Saskatchewan
It’s back at the dealer, it really had a hard time starting when I got there. Had to work the throttle to get it to stay running. Took about 6 tries to get it in reverse. Every once in a while it would idle good which makes it seem like the reeds may be ok. I think it’s either injectors or coils myself. Dealership has some real good mechanics so I hope they can solve it. No codes coming up on the 7S at all. Sled has never had plug fouling issues and it’s got over 1700 miles on it.
 
M
Jan 8, 2022
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Sanford MI
My heart aches for you- Many times I've had rare freak problems on equipment, but I did snap an exhaust valve actuating cable- the sled started fine, idled fine, went into reverse fine, accelerated fine until about 40 MPH and wouldn't go any faster- I rode 54 miles back to the truck like that-with no damage to the motor-It's doubtful that its stuck exhaust valves, oh my sled had 7000 miles on it at the time. Looking forward to hearing your fix.
 

diamonddave

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I checked the compression before it took it in the first time and it was ok.


Sent from my iPhone using Tapatalk

I was referring to the coil packs causing the dead lung. I was being lazy and didn’t want to offend SMF in my previous post. Or maybe I was being the know it all and talking above?

They can blink out and misfire at low RPM (plug foul) misfire at mid range, or they can go full send and not fire at all. Dead lung. I was agreeing with Wheelhouses post. Not saying it is your problem but possible.
 

mt.sledder

Well-known member
Lifetime Membership
Nov 28, 2007
514
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Saskatchewan
I was referring to the coil packs causing the dead lung. I was being lazy and didn’t want to offend SMF in my previous post. Or maybe I was being the know it all and talking above?

They can blink out and misfire at low RPM (plug foul) misfire at mid range, or they can go full send and not fire at all. Dead lung. I was agreeing with Wheelhouses post. Not saying it is your problem but possible.
I’ll mention it to the dealership. Thanks.
 
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