EOT Sensor

[kmoney_imp]

Just wondering if anyone could send me the pages from the shop manual concerning diagnosing the engine oil temperature sensor.

My bike is stuck in cold start mode and runs rich at 1800 RPM all the time, even after hours of riding. Disconnecting the EOT instantly returns it to a normal 1100RPM hot idle, but I was just hoping to get all the voltage/resistance readings for testing just to do my due diligence before I condemn the EOT sensor...

-Mike.

[dave]

Hi Mike, yes, I can provide you this information. How did you ever figure out that the EOT sensor was causing the high RPM? My bike had been experiencing on and off high RPM idling for some time, but right now it is working fine. How would you like me to provide you this information? I can scan it and email it if you would like.

[kmoney_imp]

Hi Mike, yes, I can provide you this information. How did you ever figure out that the EOT sensor was causing the high RPM? My bike had been experiencing on and off high RPM idling for some time, but right now it is working fine. How would you like me to provide you this information? I can scan it and email it if you would like.

Thanks for the offer and the quick reply.

My sensor was stuck at open circuit (so after actually pulling it out, it's obvious and I guess I don't need the instructions from the manual).

For diagnosis. After checking several other parts (IAC, throttle blades closing fully, TPS reset) I pulled the connector from the EOT sensor and it immediately dropped to perfect idle, from this I assumed it must be getting a false reading from the sensor.

Checking it like any other temp sensor, I checked at the connector the reference voltage (perfect 5vdc) and the ground (0vdc) and then at the sensor itself for resistance (which for mine showed open circuit). I think these sensors should start at around 2kohms and taper off to near zero when they get hot. The actual voltages or resistances should be in the manual.

I've never seen a temperature sensor fail intermittently, though I guess it could be possible. If I had to guess, our problems aren't the same -- though my bike did occasionally idle high or low when it got really hot for a while now. I'll have to see if that changes after the part gets swapped.

[Tezza_imp]

Book says 2.4-2.9k ohms. I assume that is sensor cold.

[dave]

You're welcome. My bike was occasionally experiencing low idle speed and stalling, and then high idle speed (about 1,500 RPM) when the engine was hot. Several people on this forum have reported high and low RPM idle speeds and it seemed that the only solution that was working was to replace the entire throttle body assembly (done under warranty, of course). I was going to inspect the IACV (inspect the electrical connections and examine it for sticking), but the problem mysteriously cured itself. Please let us know if this cures your high idle speed problem. Good luck.

[kmoney_imp]

You're welcome. My bike was occasionally experiencing low idle speed and stalling, and then high idle speed (about 1,500 RPM) when the engine was hot. Several people on this forum have reported high and low RPM idle speeds and it seemed that the only solution that was working was to replace the entire throttle body assembly (done under warranty, of course). I was going to inspect the IACV (inspect the electrical connections and examine it for sticking), but the problem mysteriously cured itself. Please let us know if this cures your high idle speed problem. Good luck.

I will. These bikes are odd in that what they do to reduce overheating remains kind of a black box. Mine idles down to 750 RPM or idles up to 1500 rpm randomly during long city rides when it gets hot and then returns to normal once the temperatures drop.

I wish they actually discussed what it was doing in the owners or shop manual, as just having the engine and fueling characteristics change randomly is a bit disconcerting.

[Lord Popgun]

Kmoney, This is very interesting. IIRC the service manual mentions nothing about the EOT sensor for idle problems. I'm going to print out your post and add it to my manual.

I agree with you that I wish the manual had more theory of operation on some of the systems operation.

[dave]

I will. These bikes are odd in that what they do to reduce overheating remains kind of a black box. Mine idles down to 750 RPM or idles up to 1500 rpm randomly during long city rides when it gets hot and then returns to normal once the temperatures drop.

I wish they actually discussed what it was doing in the owners or shop manual, as just having the engine and fueling characteristics change randomly is a bit disconcerting.
[/quote]

Hi kmoney. Any updates concerning the high/low idle issues many people are seeing? My bike has been running perfectly the last 1,000 miles. But, last Sunday the slow (750 RPM) idle and stalling returned. Seems to be a pattern here: The idle problems always happen when I spend time in town, at very low speeds (1st and 2nd gear), stoplight to stoplight with prolonged time not moving, and below 3k RPM when moving. I would say it's related to elevated engine temperature, but last Sunday the temperature was only in the low 70's. When I would pull in the clutch and put it into neutral at a stop light the RPM would drop to about 750, and slowly work its way back up to roughly 1,000. Is it possible that a faulty EOT sensor could be causing this? Thanks for your comments.

[Ulvetanna_imp]

Good call on this. I've not experienced any issues but it is good to know that this seems to be a simple repair.