Mountain Cat 800 Bog

[02mc800]

Hey, I have a 2002 mountain cat 800 that i'v been getting a bad bog. the bog is bad when i try to pin it. I had always been putting 87 octane gas in it untill this weekend when i put 91 octane in it. I also had just switched over to using the APV oil. The bog started right after this. would either of these be the problem? At first i thought it was snow in the intake bbut i let it dry out and that wasnt the problem. I took the intake apart and there was what looked and felt like oil in the bottom of it..?? i also tried unplugging the TSS because i was told that could be the problem. that also wasnt it. HELP ME PLEASE. any ideas???

[JohanL]

I also ride a -02 800 EFI (151").

That stock intake is not a good one. My air box is modified to be like the KingCat airbox with a snowfilter covered intake in the rear upper part of the box. Works great.

Clean APV valves and check wire spec. If for some reason... Stuck high, bad behavior at low rpm. Stuck low, poor high rpm power.

Donīt just unplugg the TSS... in the long run.
Check the TPS sensor, it may need some adjustment. Faulty adjustment will affect TSS function and fuel mixture.
There is a guide on here on how to check.

Get some high irdium performance spark plug and caps. Helps keeping things running better, in non optimal conditions. My best experience is with Denso IW27 Irdium Power.

[auburn6887]

never had my intake apert on the efis
but the t cats we had there was always oil in the intake bottom

[02mc800]

okay so you think the intake or tps could be the problem? how hard was that for you to change up the intake? i actually just took it to the dealer today to let them hook up their elecronics to it to see whats wrong. if they cant figure it out i will check these things. thanks!!

[JohanL]

 Quote: Originally Posted by 02mc800

okay so you think the intake or tps could be the problem? how hard was that for you to change up the intake? i actually just took it to the dealer today to let them hook up their elecronics to it to see whats wrong. if they cant figure it out i will check these things. thanks!!

Intake No, I have only had problems in deep powder conditions, not on trial or similar.
Itīs mostly a just getting the airbox out. Not that much spare space... A little tricky. Cutting a set of holes and covering them with some snow filter fabric. (I.E SLP pre-filter fab) And putting the airbox back in place.

When i changed my air box, I also fabricated a forward steering post mod. (Best modification made on the sled...) Required some more modification to make air box fit again.

If you can get your hands on a Ohm measurement tool. You could also make a quick check of airtemp and watertemp sensors and wires. unplugg wires from EFI box and make a measurment on cables to sensor. These two could also trick you EFI to give your engine a bit to much fuel.
There is a resistance vs temperature table in the 2002 Service Manual. Download it..

TPS. Check it, adjusted mine just slightly and it made a difference. Most notable below ~ ― throttle.