14 Polaris Ranger 900xp, single electronic throttle body. Died while riding, wouldn’t start. Wasn’t in water or driven hard as I am told. Spark is very good, was a little low on compression but should have still been able to start, (read on). Checked fuel pressure, was high by about 2 psi. Acted like it wanted to start but wouldn’t. Didn’t think fuel pressure was a problem but, know that it seems to be an issue with these so replaced the fuel pump and filter and checked the vent. Fuel does not smell bad. Fuel pressure is right on now. Still no start. Checked valve adjustment, had some pretty tight valves so did a valve adjustment. That helped the compression but still not to standard and still wouldn’t start. Next did a top end overhaul, replated cylinders and new pistons, rings, gaskets, the works. all back together, check valve timing and clearance, double check valve timing and clearance, all is good. Now compression is good, fuel pressure is good, spark is good, still has the same issue. Check oil pressure, it’s good.
Still wants to start but won’t. Don’t like to use the stuff but gave it a shot of starting fluid and it fired up. Now it will start every time when I hit the key without the fluid but, idles very poorly and when given throttle it will start to pick up rpm then bog terribly until it dies unless I back off throttle to idle. This is under a no power situation. I haven’t tried to drive it, I don’t think it will pull itself.
TPS is integrated into the throttle body and is non replaceable as a separate component. MAP sensor was replaced prior to coming to me but, I have taken it out and sprayed it clean with carb spray.
I have tried to narrow down possibilities to (1. a sheared rotor key. Although I don’t think this is the issue as when the rotor is on the TDC mark, the piston is at the top of the cylinder when looking through the spark plug hole. (2. a bad throttle body, (TPS) or other internal component. (3. a bad ECU. The trouble I’m having with the two later thoughts is that it has not thrown a code at all since the start.
I have checked, cleaned and greased several of the electrical connections. Checked relays and fuses. I’m working out of a 13-14 Ranger RZR manual that seems to be geared more to the RZR as it does not cover the single throttle body so I don’t have the specs to check it.
I think I covered everything but am most certainly open to questions, and even more open to any ideas any of you might have. Thanks!
