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Discussion Starter · #1 ·
OK,
This is my first skidoo ever and im trying to find out what most of the nice features are and how they work. I looked all through the manual and found nothing on how our what the DPM does. Someone told me that you dont have to worry about alltitude or temp. Are there sensor that monitor these? I have a 05 summit x 800ho and i think it is ideling to high around 3000 after you get of the throttle. I went ahead and adjusted the idel screw to about 1800. When i rode it again and let off the throttle it will stay at 3000 for about 30sec then drop down to 1800. What is holding it at 3000 for those 30sec?
 

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sledhead4 said:
OK,
This is my first skidoo ever and im trying to find out what most of the nice features are and how they work. I looked all through the manual and found nothing on how our what the DPM does. Someone told me that you dont have to worry about alltitude or temp. Are there sensor that monitor these? I have a 05 summit x 800ho and i think it is ideling to high around 3000 after you get of the throttle. I went ahead and adjusted the idel screw to about 1800. When i rode it again and let off the throttle it will stay at 3000 for about 30sec then drop down to 1800. What is holding it at 3000 for those 30sec?

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Mine does the same, I think it's just a cool down time, if you been pushing it hard and then shut it off it will backfire because it wasnt properly cooled down, it's good to let it idle for about 30 sec to get to that 1800 before shutting it off, then your not shutting it down when it's in a high temp.
 

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The engine is idling high (usually after a hard run) because there is excess fuel in the crankcase that is being burned off. It's OK and there's no need to fix it. Best to let it idle down to below 2000 before shutting it off. If you don't, that's when you get the backfire (excess fuel in the crankcase and exhaust). Worst of all is using the choke lever to force the engine to idle down. Sure, it'll idle down (really it's bogging out) but now you've dumped more fuel into the crankcase making it harder to restart w/o holding the throttle wide open to get lots of air into the engine to make up the excess fuel. Just let her idle down....

DPM: Adjusts for altitude (barometric pressure) and air temperature. The sensor in the air box is temp, the little hole in the MPEM is the barometric pressure sensor. The only thing DPM can do is DECREASE PRESSURE ON THE CARB'S FLOAT BOWLS via a little electric solenoid that creates a vacuum against the float bowls so the carbs. delivers less fuel as you go up in elevation or as air temperatures rise.
 

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AAA said:
The engine is idling high (usually after a hard run) because there is excess fuel in the crankcase that is being burned off. It's OK and there's no need to fix it. Best to let it idle down to below 2000 before shutting it off. If you don't, that's when you get the backfire (excess fuel in the crankcase and exhaust). Worst of all is using the choke lever to force the engine to idle down. Sure, it'll idle down (really it's bogging out) but now you've dumped more fuel into the crankcase making it harder to restart w/o holding the throttle wide open to get lots of air into the engine to make up the excess fuel. Just let her idle down....

DPM: Adjusts for altitude (barometric pressure) and air temperature. The sensor in the air box is temp, the little hole in the MPEM is the barometric pressure sensor. The only thing DPM can do is DECREASE PRESSURE ON THE CARB'S FLOAT BOWLS via a little electric solenoid that creates a vacuum against the float bowls so the carbs. delivers less fuel as you go up in elevation or as air temperatures rise.
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So you're saying it can only lean out an engine, not richen it...
 

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It returns to your base jetting.
 

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[/quote]
So you're saying it can only lean out an engine, not richen it...
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[/quote]

Yes. it leans out the motor as altitude increases and temps rise. As alts/temps go the other direction it returns to the base jetting (richest setting).
 

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Discussion Starter · #7 ·
Why is there so much extra fuel being deliverd to the crank case? Can you fix the problem by leaning it out alittle?
 

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sledhead4 said:
OK,
This is my first skidoo ever and im trying to find out what most of the nice features are and how they work. I looked all through the manual and found nothing on how our what the DPM does. Someone told me that you dont have to worry about alltitude or temp. Are there sensor that monitor these? I have a 05 summit x 800ho and i think it is ideling to high around 3000 after you get of the throttle. I went ahead and adjusted the idel screw to about 1800. When i rode it again and let off the throttle it will stay at 3000 for about 30sec then drop down to 1800. What is holding it at 3000 for those 30sec?

[snapback]258345[/snapback]​
dpm also advances the timing fo temp and altitude. the higher you go the more advanced the timing can be. I mostly jet down dpm sleds 2 sizes then check plugs you can also turn your idle fuel screws in a 1/4 turn ( less fuel at idle) on some sleds we have even went down 3 sizes on the jets.
 

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Sorry but Idle speed hanging high on a hot motor is a slight lean condition on the idle circut (fuel screw and pilot). You need to restore you idle speed screws back to where they were and tweak the fuel mixure screws out a little (richer), try a 1/4 turn. having the idle hang after a long hard pull from time to time during the day is acceptable to me, it just verifys I have the low speed circut "right there". if it's doing it all day then some adjustment is needed.
 

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Here is what my dealer said about DMP. Ski-Doo has been using some form of a compensating calibration since 1994 on their Summit line of snowmobiles. They have expanded on this technology to what we use today on most of the Ski-Doo line up. It is called DPM (digital performance management). Without over complicating the process, the DPM will keep a constant atmospheric pressure in the float bowl no matter on outside air temp (to -10f) and up to 14,000 feet. By “tricking” the float bowl pressure to assume it is at sea level it will always be able to mix at its optimum 14.7: 1 ratio. This in turn means that you get to go out and ride all day without the often-smelly task of changing your jets like the competition. Just one more reason to ride Ski-Doo “There’s nothing like it”.
 

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Good read guys.

I found that if I pop the throtle it will idle down quicker.
 
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