Turbo m7 will NOT rev.

[Wheel House Motorsports]

My dad has an OVS turbo M7 he just bought this summer. It ran pretty good when we first took it out, would rev and was a hair rich on the top end, but would periodically rev and build boost and haul arse. I tryed to clean it up, and ended up just progressively getting worse. I dropped a light on the WOT and it was running pretty good, then we started climbing in elevation, progressively got worse, and go SO bad the thing would barely move. now, no MATTER what im doing for air fuel on the box, it WILL NOT rev past 4500.. even dowhill on the trail, it doesnt matter what the box has in it, no revving, and it sorta sounds like a rich gurgle, but no matter how you work the throttle, nothing else. Is there some sorta limp mode it would go into and now will not run right at all??? I just looking for stupid things that might cause issues, My dad is ignorant to the 2 stroke turbos and im not a LOT better, so im just looking for things I might be overlooking.

+edit to add+

Once the sled started to act totally retarted, the thing idles like crap, and when coming down to idle almost dies.. We tried a new set of plugs and it didnt seem to change anything. Also, the air fuel gauge is going nuts, its an innovative wired to a little battery powered by a bridge recifier, the gauge just started doing a light show doing all sorts of spirally led patterns. the headlights on the sled are also quite dim and the tail lights dont work. leans me towards electrical problems, just not sure where to go.

 

[mmsports]

Wiring

something is defiantly shorted not sure were to tell you to start except at the injectors then the tail light if its an 05 its probably the tail light just unplug it and see if that helps unplug it above the break rotor. Good luck electrical is a blast.

 

[Wheel House Motorsports]

trust me I know.. and yes, its an 05. thanks for the thoughts.

 

[WyoBoy1000]

What he said, and Check the grounds to.

 

[Forty2chev]

I am having the same problem on my M8 09. They say with it only reving to 4K or so that there is a switch in the hand throttle that makes it do that. Its called a Throttle Positioning Switch (TPS). When the clutch engages is dies around 4K. I guess (I havent checked mine yet) check that your lefty throttle if you have one that the cable makes the throttle return all the way and check that when you apply presure to your throttle that you hear a click from the switch. I am going to look at mine tomorrow. If you would like more information after I check mine PM me.

 

[Wheel House Motorsports]

I just wanted to update with where Im at and more questions.

I got back to town and was helping my dad again. trying to eliminate things, and close in on stuff.

I am leaning STRONGLY towards electrical right now. I started off and the tail light harness is already disconnected from when we bought it, so thats done. The lights are still really dim on high or low. I ran it around the yard and it will rev to just under 8k then it dies down and wont rev past around 6500 or so and it sorta hops up and down some like a rev limiter. I checked power valves, there moving. SO, I took the sled in the garage and took off the belt and was revving it up, it will snap to 8k then just stall out drop down to 6k then bounce between 6-7k. Its not like a lean or rich, it cuts out when it revs up then comes back on and revs. it acts like a rev limiter in a car. I alos was noticing right when it would rev and cut out the gauge on the dash goes blank for an instant. Its like it doesnt have enough spark to rev the thing up.

fueling is out IMO as I have moved the box controls ALL over the place and nothing happens, it does the same thing.

you said check grounds, where abouts on the chassis would these be that I should check? the sled has definately spent some time outside, so corroded grounds or something wouldnt suprise me.

 

[bart0678]

stator

 

[Wheel House Motorsports]

I guess we got his other M7 to check against, just gotta pull it off the green one and put it on the black one.