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Discussion Starter #1
Ive been helping a friend with a 2006 Sportsman 800 and its problem started off with a really bad hesitation off the bottom end like it was too lean and back fired through the intake really bad. I did the usual checks like fuel pressure, Tps adjustment, clean the throttle body, and the only thing that helped was unplugging the t bap harness and it made it run near perfect. When I replaced the t bap sensor and did the repair harness it made no difference unless it was unplugged still. I did some more checking of the wiring and saw the connector from the crank sensor by the ecu was dirty so I cleaned it and it made the bike run great again with no bog. The problem I still have is that while idling it will randomly give off a slight back fire though the intake and die. It starts right back up and seems to go away when its good and warm, but I feel it should still idle smoothly and stay running while warming up. If anyone has any advice or things I could check it would be greatly appreciated.
 

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Have you pulled any codes off it? This should tell you what's happening

Good luck,
CW
 

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Welcome to the board!:med:
 

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Discussion Starter #6
I do have a update on the machine. Ive looked into every possible cause of this even the simple stuff like fuel possibly being bad so I pulled the tank and dumped out the fuel and to my surprise I saw metal sparkles in the fuel like you see in used motor oil when placed out it the sun. I figured this must be a sign of the fuel pump that must be starting to fail so I ordered a new replacement pump off ebay to be safe even if this wasn't causing the issue who wants metal in their fuel right? I installed the new pump, flushed the tank, and replaced the fuel filter. Once I got it installed and started it up it idled flawlessly. I let it run until it was warm enough to turn on the fan and it has never gone that long without the hick up that Ive been seeing. Next day I did the same thing no problems. A couple days later I fired it up again and next thing you know it has started doing it again. Now it does it everytime I let it warm up. If I take it out and run it hard it performs great and seems to idle fine once warm, but when its cold it randomly dies for no reason. Once again if I unplug the Tbap it idles fine hot or cold. With the tbap plugged in Im at about 1050 to 1150 RPM and with it unplugged it averages about 100 rpm higher. Needless to say its been a head scratcher and hopefully someone out there has had the same issue and if there are any tips that may help Im all ears.
 

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I've got one that's had that same hiccup issue when cold that you describe for a long time. I just learned to ignore it since it runs great otherwise. You've got me curious now to look into it. Let us know if you come up with a solution and i'll do the same.
Anyone else had this problem?
 

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Resurrecting an ancient post to see if anyone has a solution to this problem. My 08 is doing the same thing. Some days it's worse than others for seemingly no reason. As the original poster described, after it's ran for 2 or 3 minutes, everything seems fine.
 

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Resurrecting an ancient post to see if anyone has a solution to this problem. My 08 is doing the same thing. Some days it's worse than others for seemingly no reason. As the original poster described, after it's ran for 2 or 3 minutes, everything seems fine.
You may have a couple different problems.
Have you ever removed/inspected the oil pressure regulator dowel and spring? Numbers 7 and 8 below. A sticking oil pressure relief dowel can cause too high oil pressure on cold start ups floating the valves and make the engine hiccup and quit right after initial start... only to start right back up when you try it again. Not that common but it can and has happened to me on my old 800.
If you're certain its in the fuel delivery system, remove, clean and inspect the TB for wear/sticking and test the TPS. If it shows any dead spots or skips voltage while slowly moving the throttle lever it needs replaced and calibrated. If you don't have the test harness, specs and meters to do it with, you'll need to take it to someone who does. Unplugging the TBAP may be compensating for a bad TPS with a dead spot.
Let us know what you find.


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