Just bought a 98 summit 670x with 1400 miles. I found one of the quick connects (wire connectors) leading to the DPM was disconnected. It was the wire (actually 2 with one connector) leading to the top sensor on the DPM unit that attaches to the airbox. I plugged it in and the sled would bog down as soon as I gave it 1/4 throttle. It seemed like it had no fuel, or way too much-- not sure. Anyway, disconnected the connection and it ran fairly well. I was riding between 10,000 and 11,500' altitude on a 35 degree day.

I think there are 2 sensors on that unit--temperature and pressure. Which one is the top one and any ideas on why it wouldn't run correctly when plugged in? I don't want to burn a piston (running too lean), so I want to make sure the DPM is functioning properly. thanks for any help.

Also, when I pulled the carbs apart to clean them I noticed that the fuel pump was a flat rectangular pump. I looked online at skidoo's website and looked at the microfeeche and that pump looked much different than the one on the sled. any comments?

thanks

Matt

Update:

I found that the plug that was unplugged was to the enrichment selenoid. It turns out that the air pump is pumping fuel and air into the DPM. When the enrichment selenoid works it is runing the sled way too rich and bogging it out. so has anybody had an air pump blowing gas into the DPM before? if so what was the solution?

I have a 1998 670X that was hesitating around 4500-6000 rpm. I read your post and tried to unhook the plug on the air box the 2 wire one this made no difference so I unhooked the 4 wire plug to the sensors on the DPM and the hesitations stopped I rode about 80 miles like this with no problems.
When you replaced your sensor did it improve your fuel milage? as mine seems to be getting around 7-8 mpg right now.