3,800 miles

This started late this fall. Seems to do it mostly when first starting up, although I think it's done it with an up to temp engine.

Not sure if it's running on one cylinder or running rough overall. RPms drop to about 970. The roughness will come and go for a few minutes then it seems to run fine.

Has a uni filter I just put on but it ran rough before putting the filter on. Recently had the fuel pump out to fix the float, don't recall if the issue happened before doing this. All stock. I'm trying to plow snow, hard to do when it's not running right. No codes

Thoughts?

 

Look at this "sticky" post from the expert section on efi wiring problems. https://atvconnection.com/forums/pol...ap-wiring.html Usually the t-bap connector or wiring is the cause for this along with a possible tps wiring problem. 80% of the time it's the wiring or connectors,not the sensors themselves as the manual so states. Just check for any bare or soft feeling wires from these sensors that may be causing the problem.Plus the post also shows a link to where you can find stronger connectors and wiring if needed.Only The Best

 

Got a chance to go through some things. Not positive I found a smoking gun:

Checked both intake boots for cracks, they are good.
Cleaned the throttle body
Pulled plugs, they both look the same, nice golden brown
Checked the wiring on the tbap, previous owner already spliced in a different harness. I took apart the crimps and re-crimped just to make sure corrosion wasn't an issue. I didn't find anything I'd call bad.
The only thing I found is that both bolts holding the pos neg cable to the battery were not that tight. Pulled them off and cleaned, tightened back up. ATv always started fine so couldn't have been that bad.

I took the Atv out, when I came to a stop the rpms dropped to about 800rpm. Tapped the throttle and rpms came back up to the normal 1150. Did this once. Can this be a result of pulling both cables off and possibly resetting the computer? Once it warmed up it ran fine but it ran fine once warm before.

 

The oem wiring is a smaller guage than the one that OPT gave u the link for..I replaced my T bap years ago with oem and luckily haven't had any more problems but had symptoms similar to yours...also if u have a K&N air filter and u"ve been running in dusty trails they seem to cake up kinda quick which would mess with ur rpm's as well

John

 

You can always check that you have a maximum of 1/8" slack at the thumb lever plus check that the etc switch is functioning properly. Just pop the throttle cap,have the throttle adjusted.In idle and at all positions the etc switch contacts should be open. Hold the throttle just above an idle,reach in and grab the cable going to the lever with your other hand. If the etc switch is working ok,the switch contacts will close and the engine will die. My best guess is still the T-bap or Tps wiring/connectors since they were repaired once. If the previous owner/dealer used the Polaris kits,then I know they were junk as they used the same connectors and thin wiring as what was on the machine. I know because I replaced dozens of these and had to go back in and replace many again once they started failing again! Possible that pulling the battery cables may have done something,but I'd still just pull up on the wiring coming from the throttle body and see if idle changes,plus feel the wiring for soft spots(internal melting). My bets still on the crappy connectors and wiring. Remember the harness kits from Only The Best