Trouble Idling When Cold

[TBay Sledhead]

That is the idle speed adjuster.

 

[musselman]

I thought the idle adjuster was the black knob? This is on the thermostat side to give the higher idle on cold start.

 

[Crewchief47]

We had an 03 RX1 in our group that needed the valve lash done somewhere around 25,000KM with problems similar to yours(Black Spooge, hard cold start, low cold idle).

 

[TBay Sledhead]

I thought the idle adjuster was the black knob? This is on the thermostat side to give the higher idle on cold start.

Sorry my bad, I miss read. As for the setting I'm clueless.

 

[musselman]

Thanks for the help guys, I was hoping it would be something I could fix right now but the valve lash will need to wait until spring. I hope I can make it through the rest of the season.

 

[BACK COUNTRY YAMAHA]

When you checked your tps, did you actually measure the voltages, because if the voltages are out of spec it will cause erratic idle and rich conditions.

 

[northern srx]

Similar problem here ('06 RTX) that just started this year. When cold, I start the sled but as soon as it fires I need to "tip" the throttle in just sightly to keep revs at 2K to keep the motor from stumbling. After 10 to 30 seconds the motor holds it's high idle state (approx. 2000 rpm's) until the warning light goes out and all is well for the rest of the day. I'm following the advice here closely.

 

[musselman]

Well after a large ride today just as I pulled up to the trailer at the end the sled died. But this time it gave me a bunch of codes. Looks like all the codes point to the failure of one the pressure sensors, not sure if it's both or just one.

The codes were 14, 20, and 23

 

[musselman]

Something strange I noticed was when in diagnostic mode reading the value of the atmospheric pressure sensor. When I hopped on the sled and moved it around the value would jump all over the place. Sometimes it would go to 0 then other times it would go back to 96. would a bad sensor behave like this or would this be something in the wiring?

 

[steiner]

Have you checked the ground blocks?

 

[musselman]

I had a look at the 2 blocks by the primary and they looked perfect but I will go through the rest of them. Should I repair them even if they look fine?

I'm also going to swap the intake sensor over and see if the reading still varies, this will eliminate the possibility of a bad sensor.

 

[mpi xtx]

Have you checked your fuel pressure? I have seen 2 sleds with the same symptoms and both had bad fuel pressure regulators that were stuck.

 

[musselman]

I have not checked the fuel pressure, are you saying the pressure would be too high because of the stuck regulator?

I definitely think there is an issue with the air pressure sensor or the wiring though to make that value jump all over the place. I will dig into it tonight and check the wiring and ground blocks.

 

[mpi xtx]

It was causing the sleds to run to rich and idle very rough and stall sometimes

 

[musselman]

Ok made some progress, I pulled the harness out and right away saw an area that was worn through the protective sheath down in the nose of the sled. There was a pink wire exposed, touching the frame. I tested continuity from this bare spot to the plug end on the atmosphere pressure sensor and it was the same wire. This is definitely why that pressure sensor was giving false readings.

I am going to pull up the rest of the harness and check the ground blocks and for chaffing. I already repaired one ground block up on top of the valve cover, by pushing it around the value for the tps and intake pressure would flicker slightly. Hopefully this will solve all of the idle issues I have been having. This sled is a rocket on top end!!!