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mid range bog, dies when warm, first pull restart

P
Dec 6, 2018
1
0
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Good Morning,
I am having some issues with a 2012 assault 800 and need some help. The sled starts and runs fine for 6-10 minutes with a slight mid range bog. Pulls 8,150rpm with no problem but occasionally has a "dead miss" and comes right out of it in the first 6-10 Minutes. Fast forward after the initial 6-10 minutes and it goes into a bog fit in the midrange, and WOT. Sometimes at WOT it will pull 8,150rpm and shut right off like someone turned the key off... lights and gauge stay lit until sled comes to ALMOST a dead stop. Pull the rope and the thing come right back alive but when you go to move it again its in a fit of rage.. misfiring, kinda of acting like it runs out of fuel. Heres what ive done so far..

Stator: was claimed to be replaced by the previous owner.
ECU: i just replaced with Brand new, and had it programmed by dealer. ( No fix )
EV solenoid and piping: taken off a known running sled with same P/N's ( no fix)
EV's: Cleaned by myself. all passage ports, bellows cleaned and inspected etc. ( i dont trust many shops, Also no fix )
Voltage regulators: ( there are two ) taken off a known running sled , Also no fix )
Capacitor: swapped from a known running sled ( no fix )
Primary spring: not broken
Compression: 128/128PSI
Charging at approx 12.7V
Had EV solenoid code, cleared it and ran it again into its fit, never came back.
fuel pressure: constant approx 56-57psi ( harbor freight gauge...) idle, mid fit, and WOT it doesnt deviate.
checked all wires i could see.
Plum full tank of fuel...

I am at a total loss with this thing...

Ive searched high and low and cannot find anyone with a problem exactly like this. happens everytime when ran from cold to warmed up, 10 minutes and it acts up. let it cool and it will do it all over again.

Sometimes it doesnt start and you have to hold the trottle open to restart, and sometimes reverse button once its hit will turn the sled off.

Please someone help. im ready to watch it burn.

Ps: Dealer just replaced battery and speed sensor, havent gotten the chance to run it yet.
 

Solarguy

Well-known member
Premium Member
Jun 23, 2011
1,139
1,077
113
NW Montana
I'd try a throttle cable adjustment, had a couple sleds do funny things that were cured by a cable adjustment. Make sure the lever has some play, mine had tightened through vibration and simply loosening a bit solved the problems.
 
H

Hansen13

Member
Oct 22, 2011
164
21
18
31
Cranbrook, BC, Canada
My similar (Not Exact!) issue turned out to be coils. It'd be great until they hit a certain temp then one would fail basically killing the sled. Chuck snow on them and you could ride it all day. They'd get heat soaked. Replaced coils and issue was gone.
 

Scott

Scott Stiegler
Staff member
Lifetime Membership
Nov 1, 1998
69,618
11,737
113
51
W Mont
And if all that doesn't work, I'd have the dealer go through to calibrate AND set the TPS.
They must be calibrated before they are set.
 
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