Hey guys! I'm new to the forum and looking for a little sage advice. I have a 2009 Sportsman 500 HO EFI and it started running terribly on my last ride. It starts right up and idles all right 1150-1200 rpm, but once you give it throttle it misses (sounds like it only fires every other stroke) until you give if full throttle and then it runs ok. It also backfires under compression going down hill. The check engine light comes on intermittently. I have tried going into diagnostic mode to get a code (Turn ingition to on position and then turn off and on three times in less than 5 seconds) and it will not go into diagnostic mode. I have a K&N air cleaner and it is always cleaned. I changed the NGK plug (old one looked good, no fouling). I looked for wiring problems with the EFI and saw that the yellow wire coming from sensor (not sure which one, three wires mounted on top of air intake) had the casing worn off but the wires looked intact. Any help I could get on this would be greatly appreciated.

 

Thats the t-bAP sensor and the wiring inside is most likely broke, they make a repair kit for the problem.

 

#2876315 map sensor repair kit as mentioned,plus make sure the rubber grommet isn't split,had several that would split because of the vibration. OPT

 

Back on the trail thanks to RickCJ7 and Old Polaris Tech. Tested the T-BAP harness and the orange and purple wires came right out. Decided against buying the OEM harness scince it is the same gauge wiring as the stuff that broke. Made pigtails using 16 GA.22 strand connected diretly to the sensor.I filled the sensor (connector cavity only) with RTV blue silicone (sensor compatable) for vibration dampening and weather proofing. I then slipped the whole harness assembly through a section of old bicycle inner tube and secured with a zip tie to eliminate any future chaffing. My ride once again is happy!! Thanks for the help guys.