I have a 2007 Sportsman 500 EFI all stock with about 1000 miles on it. A month ago it started running rough, missing, at 15 to 20 mph cruising rpm on some OHV trails in central Oregon. Was able to accelarate with smooth power out of this kind of, lurching it was doing. Here's what I did: changed the plug (old one looked normal), changed the air filter (old one not too bad, had been changed before), put a new tranny belt on (old one slightly glazed and minor cracking), put new, clean gas in tank (gas I had in the tank had Sta-bil fuel stabalizer in it at the proper mix, 91 octane). It rode a little better but still had the hesitation but had good acceleration.

Rode it a week later mainly on gravel roads and alot of climbing of fire roads for about 40 miles with no problems.

2 weeks ago, about 45 minutes into a ride on level ground (not hard riding) it started missing, died once, restarted a little hard but ran rough back to the rig. This time I had a check engine code flashed at me. Checked the code at home in my service manual and it is a code 45 (barometric pressure sensor: MAP circuit low input). Haven't got a clue. Can't find the sensor or is it just the manifold air pressure sensor that needs to be checked/changed?

Have a new external fuel filter I am going to put on tomorrow. Would appreciate any and all suggestions. Thanks for a great forum for us guys who like to get in trouble in our garages.

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2007 Sportsman 500 EFI
2007 Hawkeye 300 4x4
2008 Scrambler 500 H.O.

 

I've had the exact same problem with both of my stock '07 Sportman 500 EFIs with about 300 miles on each. Last time I as out I had changed the plug and air filter and they both were spitting and sputtering at about 15-25 MPH. If I floored it, it ran great. I've now taken both gas tanks off and drained them, replaced both fuel filters and cleaned the plugs that I could get to and put dialectric grease in them. I'll hopefully take them back out for a ride in a week or so to check them out. The Polaris dealer here in Alaska told me to check the connections around the throttle body for leaks, cracks, etc. So far, nothing. If you have any thing that works out, please post an update and I'll do the same.

 

i know on some bikes they are saying the t bap senor harness is going bad.

 

I have a 05 700 EFI and it is doing the same thing. The bike starts and idles normal. When I accelerate and level off at 10-15 mph, it begins to sound like it is missing with a bunch of sputtering. If I get on it and accelerate, the bike sounds normal. On deceleration from higher speeds, I will get a backfire or two.

I have changed the gas, plugs, wires, fuel filter and checked the coil ground issue. I am at a loss. The only other thing that I have read on here is that the pressure regulator in the tank could be going bad. I am going to try to trouble shoot that in the am. Any other ideas? Have you been able to fix your machines?

 

I had missing, sputtering, and backfire on occasion. Sometimes it would run great but act up for not reason. Ended up being a bad ground on the battery, it had worked loose. I tightened everything up and it has run great since. These bikes need good connections, clean and tighten everything.

 

Thanks for the post guys...I have changed the plug, fuel filter, air filter, cvt belt, and added seafoam to clean gas. Only drove it around the house, a couple hundred yards. Starts and runs great. Took the +battery terminal off for a couple minutes to see if the the trouble code 45 was cleared. Still there. Going out on a long ride, hopefully, this weekend. Next step for me after checking all electrical connections, which I've done most of it seems, is to replace the MAP sensor. That's where the code 45 sends me. The cheapest I've found on line is $73 bucks. Anybody know cheaper? Thanks again guys. Happy trails.

 

hey , new to the board, have 2007 sportsman spuddering, lurching,sometimes backfire. same problem everybody else had. new plug,gas, ecm,adjusted map sensor. $700 later same thing. any help? thanks lineman1

 

Welcome to the forum! Adjusted map sensor? Guess you mean adjusted tps sensor. Did you replace the map sensor harness with the replacement kit that's offered? The wires can have a bare spot or can break internally or they can actually pull slightly out of the connector causing problems such as throwing codes,backfiring at idle,hard starting ,etc. This has been a recurring problem on the map sensor wiring. Look at the "sticky" in the expert sections on the wiring problem on the 700 and 800 efi models which applies to all efi machines. Heavier duty map sensor harness repair kits are available. Also look at the crank sensor harness wiring and connector running under the throttle body close to the starter. Have found wiring shorts there that would do the same thing.OPT

 

I had troubles like this and it turned out to be a battery issue. Ran great for a couple weeks and then it started up again. Turned out to be a loose battery connection this time around. Put Loctite on the threads with star washers and it's been good since.

 

update, got my t-bap sensor harness from otb powersports, installed been running great so far. had a broke wire right next to plug couldnt tell to you pull each wire . thanks eveybody