I’ve had my 08 500 Touring EFI for about 3 months now. As you guys have seen I’ve added a few things here and there (haven’t you all) and I’m really enjoying it (as are my kids). Other than my second puncture this past weekend (do I hear Bighorns calling?) things have gone well. I’ve gone as far as 90 miles without having to add gas, and I’ve never needed more than 4.5 gallons to fill it up (despite the gauge flashing like crazy). One of these days I'm going to run it dry to see how close I can get to the rated capacity of 6.1 gallons. I’m averaging in the 18-20 mpg range so I’m happy enough with the mileage vs. power trade-off I made with the 500 instead of the 800.

All of my riding is at 5,000 ft and above, however I definitely get the feeling that at altitude (7,000 - 9,000 + ft) the quad is bogging down. I know that power drops as you go higher, but in a couple of sticky situations I thought it was going to stall on me (not where you’d want to either). I pulled the plug and it looked like it was running rich. The reason I mentioned the mileage above is that I’ve read on the forums that others are getting as good as 22-24 mpg. My 17% lower mpg would support that it’s running rich. Everything is stock and I had the quad serviced at 20hrs (it now has about 40 – 50 hrs on it) and the air filter looks ok.

How much does the EFI compensate for the altitude?
Is there anything I can do to adjust the mix?

Any and all other ideas are welcome!

 

38 views and no ideas? Not even a cheap shot?

 

They are re-flashing the computers on some to make them run right, I think most of them were too lean though, polaris doesnt run right unless the plug is black from being a little rich.

 

Thats pretty good since the ATV only has a 4.1 gal. (15.5 l) gas tank. http://www.powersportsnetwork.com/en...icleCode=55633 I have the larger 5.25 tank and it gets 100 miles so your above 20 mpg.

Not sure about your other problem I thought EFI cure all those troubles.

 

TLC - the two seaters (Touring and X2) have a 6.1 gallon tank.

Kerbirds, thanks for the tip, I'll check with my dealer.

 

Mick;

Their is such a thing as buying crappy gas and having a heavy thumb!

 

With the bogging issue, the only way around the OEM efi program is to purchase a power commander usb if you have a laptop. This mod works very well. By installing this on your 500 efi it will lean it out to power commander sees fit for your atv. And no polaris don't run well rich to wear the plug is black or dripping oil. I had this engine just wasn't efi. I purchased a power commander so I could set my own program due to performance upgrades. If I can run my atv at -20 celcius in Canada you won't have a problem with the commander and it's a simple install with instructions.

 

Even though less air is coming in and therfore less fuel is required at altitiude for a given throttle setting you also have to run a higher throttle setting to compensate for the power loss. When running upwards of 9000 ft power will be down MARKEDLY...rule of thumb is for N/A internal combustion engine is 3.5% for every 1000 ft of DA...
With that said Polaris EFI will compensate for altitude but I wouldn't be suprised if it doesn't have range of self adjustment to have a perfect mixture at 9000 ft above sea level..way better than a carb jetted for sea level though.
You might want to look into a clutch kit set up for altitude.?

 

I have the same ride, two of them, and seem to be getting better MPG's than you. I've also run above 9000 ft in Utah and didn't really feel a power loss, even when carrying two. Sounds like your assessment may be correct.

 

That is interesting..because there had to be a pretty significant power loss. What altitude are you used to riding at? There are more factors invovled than just altitude above sea level..barometric pressure,temp and humidity are factors as well...so it is possible to have a DA of less than the actual altitude MSL.

MickJP..Have you tried replacing the plug and seeing if it still does it? When it sputters it is misfiring..which causes loading up....so the plug can be black if checked shorlty after sputtering..also if you check the plug after letting it idle you are only seeing the idle mixture...nothing else. If you want to see the mixture under power you must shut down the engine at that throttle setting. You could always have the T-MAP sensor checked..if it was giving an inaccurate signal then the ECM could not correctly determine the required mixture. In the absense of a mechanical problem the T-MAP and TPS sensors would be something I would check if the mixture was off.