Tps/Ecu problems? 09 Dragon 800!!!!

BigMike13 · Feb 6, 2017

Hey Fellas, thanks for any info.... I'm a newbie!
So I'll try to be brief, not sure I can be though....

Couple weeks ago I bought an 09 800 Dragon from a dealer, seemed like a great deal, 1200miles 4k.... get home and ride for about an hour, I was happy, until I hit the straight strech headed for home, as soon as i hit 7000rpm it defuels/limp mode.... No matter the conditions if i hit 7k rpms it goes into limp mode. I've also noticed some sort of issue with it idling at different rpms sometimes low sometimes as high as 3500 after riding for awhile.

Not real happy with the dealership. Definitely feeling taken advantage of, but I'm not taking it back.

I've been doing my best to read everyone elses threads and problems so I dont rehash things you guys have already discussed. Im planning to get the Pcv and will wait till summer to install a Dragon fix kit of some sort, but I'm nervous that it'll scatter engine parts all over if i continue riding it, so i've been reading alot of info and decided to try and check out the Tps also some thought that the Ecu or regulator could be involved? I've built the Tps tool and struggled through taking the Airbox off for the first time... haha... not as easy as i would have imagined.

So now I have the throttle bodies removed and notice that they are pretty dirty and oily, I'll attempt to add a pic here also. I'm thinking that it cant be normal to look the way that they do?
Maybe I'm wrong but wanted to get somones opinion before i clean it up and slap them back on.

Any other info that you guys can give me would also be great! Will clean up the airbox/ Can I seal it with epoxy or silicone? Any other maintenence things I should do while I've got it this torn apart?

Much appreciation to you guys on here helping strangers like me out.... Thanks Mike

XCaSSAULT · Feb 6, 2017

The first time I took mine apart I was also shocked at how dirty they were. A lot of belt dust going on under the hood and gets its way in there. Sealing the air box is a must. I used lacquer thinner to clean the seam really well and then used black gorilla tape. Has held up well for 1 and a half seasons now. Check and clean the reed valves also well your in there.

As far as the problem. Any check engine lights? I'm pretty new to these machines as well but kinda sounds like maybe the tps sensor is bad. With volt meter hooked up slowly move the throttle plates open and closed and the volts should smoothly go up and down. A analog volt meter will show this better with the needle sweeping smoothly, but a digital one will aslo work. If there's any flat or open spots in the volt movement then it's bad.

There's no way to test the ecu as far as I know but if u look at the bottom of it check for any melting or bubbling of the material.

Otherwise just go over all your electrical stuff with a service manual and test components and look for shorts in wires etc. try obvious stuff first too like changing spark plugs, fuel filter, check/clean exhaust valves.

Also while you have the t-body off check your oil pump. They were usually way off from the factory. I checked mine once and thought it was right but turns out I was looking at the wrong line. There's a small bump on the arm that lines up with a line. Spray carb cleaner in there and scrub with a tooth brush, then check with a good mirror.

sledhed · Feb 7, 2017

Agree with prior post, except I would reseal the airbox with black silicone and add small zip ties through the fasteners that snap the two halves together if you need to pull the halves together at all. Also make sure the intake seals to the hood when closed to keep the belt dust out.

Check the intake boots for delaminating or cracks, I had to replace mine as it was starting to come apart and will give you high or erratic idle. Catch it early or you will lean out the motor, if it is delaminating from the metal backing plate at all.

Watch your voltage indicator on the right side of the gauge while idling, it should be steady and at least halfway up the gauge if I recall correctly.

Run a compression test, you can also pull the exhaust valves and peer in and check piston condition.

PCV with a map to richen midrange is a good idea with these sleds, I ran without one but made sure not to stay in the midrange long, in and out of throttle with occasional WFO keeps the ride interesting anyway.

I probably would have taken it back to the dealer right away just to see if they would stand behind it, or at least split any repairs with you or eat the labor... or I would not darken their door again...

BigMike13 · Feb 12, 2017

Thanks for your replies guy's! allot info that I will help me out in the future!

Just an Update: I built the Tps setting tool and I feel like I got it set right and the analog volt meter showed smooth throttle, but when I started it up it backfired and idled at 3150 with excessive smoke. I shut it down and will await the arrival of an ebay Tps so I can try it again! Hopefully the used one is in good working order.

Still made a trip to one of the most incredible places on earth with the older sleds today! Picture attached..... Mike

sled_guy · Feb 12, 2017

Just went through this exact symptoms with an 08 800. It ended up being the computer.

Here was my test procedure:
1 - Put sled on stand, start and let warm up good.
2 - With the old computer installed, run the rpm up to engagement and start reving it up... at between 6500 and 6800 it would hiccup, backfire, and by the time you hit 7000rpm it would nearly die. Let off the throttle and it would return to idle fine.
3 - Plugged in known good computer and repeat. It would pull right up to 8000rpm and even beyond on the stand until I hit the rev limiter.

Repeated 3 times to make sure, same symptoms each time.

Now I'm not telling you it is your ecu, but that is my experience.

You might ask the dealer you bought it from to at least put it on the Digital Wrench and see what they see.

sled_guy

BigMike13 · Apr 5, 2017

So just a follow up here to my journey! I ended up taking the Dragon back to the dealer, and to my surprise he was more than helpful (lent me his personal sled while he fixed mine, as he didn't have time to ride anyhow). So upon my arrival they put the sled on the computer which showed that it was throwing a code for Detonation, no other info. They manually checked a few connections and couldn't find anything wrong at all. So we decided to split the cost of a Dragon fix kit.

When they did the tear down for the fix kit installation they found a very small crack in the bottom of the cylinder, well below the area I would think had extreme pressure during fuel burn. (but I don't claim to be smart):face-icon-small-win

So after the Dragon fix kit and a complete new cylinder head, I ended up paying $780.00, which I'm pleased with, especially when you factor in over 100 miles on a 15 RMK Pro.

So I get the sled back and while driving home I pulled over rode for about 10 minutes on a flat twisty road. I was able to get it warmed up and hit 8000 rpm on a couple straightaways, with no check engine light!!!!, which made my day! I was pretty skeptical that the tiny crack at the bottom of the cylinder skirt could have caused detonation, but like I said, what do I know?

5 days later I get time to ride, about an hour into the ride I see that I've got a check engine light and that my dash display has gone blank:brokenheart:

Another trip to the dealer and he diagnoses the problem as a burned up voltage regulator. Thankfully it apparently did not burn up the Ecu, which I've read is quite common. Dealership bought the regulator and I paid $30.00 shipping..... :rockon:

I've since been able to put about 10 hours on it and haven't had a problem, other than a broken belt, which only had about an hour on it, although it was a cheapy.

Overall I think I'm right in the middle of the satisfaction scale. Could have been a better experience, I did miss out on quite a bit of riding that I wouldn't have otherwise, but could have been a lot worse obviously!

Thanks to the guys who have helped me and thanks for reading my ramblings! cheers, Mike

sledhed · Apr 5, 2017

Glad to hear it is resolved, and that your dealer did the right thing and went above and beyond from the sounds of it. When I had my original Dragon 800 the prior owner went through all the hassles with the motor and sold it to me on the cheap (for trade-in value), then it was flawless for me for years... I did have a VR blow and burn up the ECU (newer VR part numbers protect the ECU and just kill the sled basically). My local dealer submitted it to Polaris as it was just out of warranty and they replaced the ECU and VR on a "goodwill" basis

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Tps/Ecu problems? 09 Dragon 800!!!!

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