This is my first post. I've owned a 94 SP 400 and just upgraded BIG time to the 800 which I got back at the end of Dec. This past weekend was my first time out in the swamp with it and the swamps were perfect because the frost is still there, down about 6" to 8" so you could go just about anywhere. We hit a few holes with some water maybe about 4" to 5" above the footrests not a problem but I made a rookie mistake and still was in high range, it was hard to tell on the 800 with all the power, so I smoked the belt a bit, put in low and climbed right out. With the old 400 I would have put it in low right from the start.
After getting out of the swamp we were heading back to the cabin about 3 miles down the road and about half way back the 800 starting back firing anytime I was under acceleration and the check engine light came on. I nursed it back to the cabin looked it over couldn't find anything wrong, disconnected the battery to reset the computer started it back up the light was out but the run up and down the road it was still back firing then the engine light come on. I loaded it back up in the truck and drove home unloaded, started it up no light drove it up and down the and no back firing. The next morning wash the 800 off, up and down the road again running good. Has anyone else had this problem? Was it something getting wet? or hot? Thanks.

 

When we first got our 800 it would flood out really easy. It back fired a couple of times but we have not had ours in any wet conditions yet. Have you looked at your air filter to see if it's wet or has anything in it at all?

 

I would also take a close look at the plug wires where the connect to the ignition coils and on the plugs, be sure they are tight and it also wouldn't hurt to put a little more silicone dielectic grease in the boots... I read on here about the wires being loose on some of the
EFI's. Let us know what you find.

 

Did you put it into diagnostic mode to pull the codes?

 

no problems here, ive been throwing my 800 into 3.5 foot deep water and jumping it.

sorry i couldent be of more help

 

Thanks for the info. I've made appointment in my garage for Friday night to dig into this problem. I'll go through all the wires in the ignition system that I can check out. I'll have to go back through my owner's manual to see how to get into the diagnostic mode, I thought there was only one way to check with the port on the headlight pod. Hopefully it nothing but a loose wire so I can going riding this weekend.

 

I didn't find anything wrong with the wiring, but wow I was amazed how easy and fast it was to take all the plastic off the wheeler. I had it stripped down in under an hour, looked everything over and the bad thing I found was when I took the clutch cover off I found a light coat of oil or grease on my primary clutch sheaves. I sprayed some brake cleaner on it and wiped it down, after removing the belt and cleaning it also. I'm going to check it again this week if there is more oil then I'm going to remove the clutches and check the seals. I put it all back together and rode about a 120 miles this weekend without any problems and riding through some water. AND YEAH I LOVE THIS WHEELER!!!