This is all based on extensive car knowledge, as I have no experience w/efi bikes @ the moment. But I would triple quadruple check for any air leaks between the maf & engine (including the pcv system if there is one), assuming these bikes have a maf of course, I don't know. Also triple check every electrical connection, especially for maf, TPS & crank/cam sensors (assuming these bikes have some of these).

Basically check and check and check check some more for any intake air leaks or bad connections/wiring issues, these two things are usually the cause on cars that aren't spitting out a code, but I'm sure since these bikes aren't obd-II compliant that there isn't a laundry list of detectable dtc's.

 

On a 2 year old machine though? I know that's a common problem on older 2-stroke quads, but on a 4-stroke it wouldn't make any difference, unless these bikes have a recirculating vacuum pcv system like many cars (Crankase is under vacuum during most conditions & it has an inlet that is pre throttle body but post maf sensor), but even so it would have to be SOOO BAD to cause idle issues & would probably be pissing oil first.

 

The bike has 200 miles on it. Has not been used much. The original problem I had before I took it to a dealer was the digital instrument gage showed an overheating problem, but the machine was not overheating and the fan was turning off and on correctly. When the overheating indicator came on the bike would go into a limp in mode and had very little throttle response. It was giving me two codes.
One was a (42 Engine Temperature Sensor Circuit (ECT): Low Voltage) and the other was (45 Barometric Pressure Sensor: MAP Circuit Low Input) The dealer said there was a problem with Engine control module, so they installed a new one. Well the codes went away along with the overheating light issue. Now it seems to have no high speed idle when the engine first starts up for the first time like it used to. Then the engine wants to stall and other times it will idle at 2000 plus rpm. Sometimes when the engine is idling and wants to stall I will give it a little throttle and you can hear it missing a little through the exhaust. The dealer did not do me any favors when he worked on it. I took it back twice and still having issues. Any help would be appreciated. Also the fuel tank is full.

 

If anyone on here could get a hold of a service manual for me I could take a look at it and see the next steps, if it was a car I'd say plug a scanner into it and look at the ect & map sensors. The service manual should have some resistance and voltage readings under certain conditions for both of them. The japenese cars I am use to working on NEVER toast control modules, but in this case that is a real possibility, first check that it's inputs are good, especially the important ones like cam/crank (If your gauge displays rpms correct this can rule that out usually, not sure if your bike even has a tach though) tps, map, and ect to some extent.

I worked at a bike shop years ago, and it was common practice to test exciter and cdi boxes by applying slight pressure to the case with a c-clamp, it didn't always rule it out but sometimes it would rule it in (If that makes sense), allthough with todays efi machines I'd suspect a software issue first.

If it was my bike or in my shop I would do the following:

Triple check all wiring & vacuum again, just for fun, I know you've done it AND the bike has low hours but sometimes stuff is really easy to miss. I just fixed our crazy high tech washing machine by taking the panels off and making a very thorough visual inspection before calling in the pros, I found a vacuum hose to close to the big wash bucket & it was chafed up (I know, it probably isn't a vacuum line, but it sure looked like one)

Get a service manual and check all of the input sensors at the ecu, you'll need a dmm or similiar.

If all else failed I'd try my hardest to find someone else local with the same machine and start swapping parts, maybe a member on here would let you mail them your ecu & map for testing, worth a shot right? If all else fails send it off to someone else like a DIFFERENT polaris dealer, or an independent or different brand dealer with a good service department & the same machine on their lot.

 

the dying can be as simpel as the throtel safty on the handelbar if it is like mine if u accidently move your throtel cabel enough the conecthions in it will make it not idel just tru moving the cabel around . if u can pop the top of by the trotel u can see the conecthions if they are touching it wont let your atv fier becouse it thinks u broke the cabel

 

if the polaris engine is one with an engine that is seperate from the tranny then it can be crank seals. the left side of the crank come out and drives the primary clutch and has a crank seal behind it.

 

Is there a way to test for the crank seal leaking. To bad to replace this seal if it is good.

 

Find the PCV system (Assuming these quads have a circulating type, IE it is vented to the intake tract somewhere) It will be a hose, probably 1/2" in size, and it will run between the intake boot & the engine case. Block the hose where it goes into the boot and leave it open on the engine crankase side.

Just for others reference, this is NOT how you would check it on a 2-stroke, and I still doubt this is the issue.

Did you quadruple check all of the connections? I recently came across some posts mentioning it is very common for the map wires to fray right near the connector.

 

Hey skunksqasher, Did you say that you still have a 2007 polaris Sportsman ATV 500 EFI. If you do, could I ask a favor. If you lift the seat off and the air cleaner tube you will be looking down at the top of the throttle body that hooks to the air cleaner box. On top of the throttle body there will be a black plastic MAP sensor that is held in by a metal clip. The MAP sensor has a connector with three wires going into it. From sitting on the seat and the plastic connector still hooked up to the MAP sensor could you tell me the order of the different colored wires going from left to right. The color of the wires should be Violet,Orange and Pink. This is not the order that you will find them in. The dealer that worked on this last had installed a new wiring end and I believe he may of wired it wrong from what I am seeing. Hope I did not give you to much detail.Thanks in advance for your help. Also if you sent a picture that may answer my question.