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2012 Ranger XP800 - surging idle - finally solved

4K views 25 replies 5 participants last post by  bigtwin.ok 
#1 ·
I spent hours on the forums reading all kinds of suggestions and tips to find and address the idle surge that was causing me havoc trying to get the rig in and out of gear.

Belt, bearing,tps, wiring, fuel, check valve, breather tube, air filter, etc…

I gave up and took it to a local dealer who was also perplexed and tried everything I had already tried.

on a whim the tech pulled my throttle body and it was caked with oil. He then wiped it all down, sprayed it clean and reinstalled the unit and to his surprise the surging idle stopped.

If you’re at your wits end and have done all of the above, pull your TB and check it for a coat of oil.

my rig has 1400 miles and just under 300 hours. Yes, it averages about 4.5mph.
 
#2 ·
"on a whim the tech pulled my throttle body and it was caked with oil. "

socal, if the throttle body was coated with oil I would be checking the compression . I would also suspect the TMAP and the air filter are also getting oiled up probably from excessive blowby the rings. That is not a lot of miles/hours but a cracked throttle body adapter, which they are known for, will allow dirt to enter the engine causing the excessive cylinder /ring wear .
 
#7 ·
Jungleman made me paranoid that I hadn't done my due diligence on checking the throttle body adapter so I went back and emptied about half a can of carb cleaner all around the base ensuring I got behind it.

Still no idle jump, but it's super clean now.

Rowedoo, where is the PCV valve?
 
#14 ·
Hey guys, on a 2012 800, there is a breather that has a reed assembly on the valve cover identical to the 700's. The breathers tend to warp, especially on a 800 and let oil film trickle down the valve cover . You can purchase a billet aluminum one on EBAY to cure the exterior oil/leak.

You can clean or replace the reed assembly with one from PARTZILLA (possibly available on EBAY.).... Normally when the throttle body is getting oiled, it is from blowby from the crankcase which is being pressurized because of ' lack of ring syndrome'. When you have LORS...........normally the TB, the air box boot and the air cleaner also get oiled down . I have never seen the 'oil cake' magically stop at the throttle body but perhaps it is a mild case . See PARTZILLA parts ..There is no real 'PVC' valve,just the reed assembly (#3) under the breather cover. (#5)

I would at minimum get a compression tester from HARBOR FREIGHT and check with BOTH plugs out and WIDE OPEN THROTTLE . Engine hot..

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#16 ·
I spent hours on the forums reading all kinds of suggestions and tips to find and address the idle surge that was causing me havoc trying to get the rig in and out of gear. Belt, bearing,tps, wiring, fuel, check valve, breather tube, air filter, etc… I gave up and took it to a local dealer who was also perplexed and tried everything I had already tried. on a whim the tech pulled my throttle body and it was caked with oil. He then wiped it all down, sprayed it clean and reinstalled the unit and to his surprise the surging idle stopped. If you’re at your wits end and have done all of the above, pull your TB and check it for a coat of oil. my rig has 1400 miles and just under 300 hours. Yes, it averages about 4.5mph.
I have a 2011 XP 800 and it started surging when at idle making it impossible to shift until rpm’s dropped back to 1450. I’ve not noticed any acceleration issues. Is there a gasoline additive I could use vs pulling the throttle body?
 
#17 ·
big, 99 times out of a 100 on a 2011 800 your surging is caused by a BAD IAC harness. Polaris issued a TSB and replaced a ton of these harnesses back in 2012 with the same skimpy harness that went bad... This OTB IAC harness is permanent.. Idle Air Control Motor Wiring Repair Harness
 
#18 ·
big, 99 times out of a 100 on a 2011 800 your surging is caused by a BAD IAC harness. Polaris issued a TSB and replaced a ton of these harnesses back in 2012 with the same skimpy harness that went bad... This OTB IAC harness is permanent.. Idle Air Control Motor Wiring Repair Harness
Thank you very much! My harness was replaced but as you said, they used the same harness and eventually it went bad. Do you know if I’ll need the 7 or 14” harness?
 
#19 ·
That, I have no idea.... See if you can locate any chaffed/broken/bent wires//
 
#21 ·
I went looking for the connector and when I removed the seat on my 2011 XP800, I found my seat belts and buckles wadded up under the seat. When I located the connector, I pulled it upwards, trying to relieve a little stress on the wires in the connector. The seat belts and/or the buckle may have been pressing down on the connector. Bottom line, after removing the seat belts from under the seat and tugging upwards on the connector, my machine has idled perfectly the last 5 times it’s been started! Perhaps I won’t have to replace the harness.
 
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