2011 Sportsman 800 EFI hard starting when cold

[JJ76]

Hi,

Have big problems to start my Polaris Sportsman 800 EFI 2011 for the first time of the day, engine cold. Outside temperature has been below 15 degC. Engine does start, but shuts down after just few seconds and spark plugs are flooded. I could find a lot of question regarding the same issue, but no answers, so I assume this is quite general problem. I have checked/tested following components with known good ones, ECU, TMAP, ignition coil, spark plugs. Have checked the resistance between wires from all sensors to ECU and all show below 0,7 ohms with my multimeter. Have replaced fuel pump assembly. Have checked the timing from gears and all marks are aligned. Checked the compression and it was ok, also same on both cylinders. TPS is within limits. ETC switch checked. Have new fresh 98oct fuel in tank. No fault codes on display. Have checked the air intake, no leaks and new air filter in place. Now have opened up the engine, but so far could not find any obvious reason from there either. Piston rings look ok, hydraulic tappets moving freely. Funny thing is that once engine has warmed up, it runs perfectly.

Does anybody have any idea what is wrong and how to fix it.

BR

JJ

[Ajmboy]

This sounds like a fuel management problem on cold start which I believe is controlled by the T-BAP sensor on EFI models. Some have replaced the harness as well or only the harness. Maybe try jiggling it around.

Amazon full kit: http://amzn.to/2ddFoiu

Amazon harness only: http://amzn.to/2e95Omf