Alright guys, I have a 2007 CBR 600RR. I have had issues with the idle for the past month. Here's the deal: RPMs would go up and down when riding around with clutch disengaged (bouncing off the 1, 000 RPM mark=almost like it is stalling/in limp mode). Then after a few days of riding, the bike idles higher at normal engine temp and will idle even higher with a rev of the throttle (~2,000 rpm). There is decreased engine breaking when using gears to slow down and bike jumps a little when shifting gears (like throttle is being held down=obviously the high idle issue).

After all this, I replaced the IACV (air intake control valve) to no avail. Decided to say screw it and took it to the Honda dealership. They hooked her up and said the air intake temp sensor (IAT) was throwing a code. They reset the ECU and said it was good to go. The tech said further that if it does the same thing again, I should replace the IAT sensor since it has gone bad.

My question is this, my bike never threw a FI light blinking code or anything of that matter. So, how can resetting the ECU temporarily fix a faulty IAT sensor (if that's the case)? The part is $15.00, so I am not too concerned about it. And it is easy to replace. I just wanted to see if anyone had this happen, has an answer for me, and to let everyone know that this issue is NOT always related to the IACV.

Thanks in advanced guys!

 

Resetting the code will not fix the issue. What it will do is tell the mechanic whether or not the sensor is bad. If the bike throws the code again, it is suspect of being bad. The code is reset and the bike is restarted. If the bike doesn't throw the code right away, there is a chance the sensor is not bad. If it throws the code right away, the sensor is more than likely bad and can be replaced. Basically, they are trying to rule out the possibility the sensor threw a false code. the codes are stored for a long time and any number of reasons could have thrown the code. A previous owner could have unplugged the sensor with the bike running years ago and the ecu will keep a memory of it. So the code could be just a false code. Also, generally you won't get a fault light unless its a constant code being thrown.

Having said that. I would just buy the sensor and replace it. It sounds like your bikes issue is related to the temp of the bike. The AIT sensor plays a role in the air/fuel mixture for the fuel injection and could be the cause of your issues. for 15 bucks, I'd try it.

Have you recently serviced or added any components to the bike?

 

Thanks for the input. I only changed my oil myself over the summer. I talked to a mechanic and says it sounds exactly like the IAT sensor is bad.

 

Provided it's not the sensor, the symptoms you describe are also indicative of an intake leak. Spraying carb cleaner around all intake connections is one test. If the idle changes when you do, you've found the leak.

 

Ahh, thanks Jim T. I will look into that if the sensor is not the issue.

 

Thank you everyone for your input and feedback. I placed the new IAT sensor on the back a couple of days ago to no avail. I am not sure exactly what happened but the bike is running fine now. I started it after jumping the DTC mulitple times today trying different combinations of wires. Anyways, I started the bike and just let it idle for about 5 min. It seems to back in action as far as I know now. For future reference to anyone who finds this situation interesting. I never had a MIL with this entire experience. Yet the dealership found an error code in the ECM for a faulty IAT sensor. Go figure. Guess the ECM is slowly adjusting now, that is my guess.

 

The connection at the connector for the IAT could have been the problem. I've found that connectors and couplings on bikes of all types are often the source of electrical problems

 

Hey Jim T. So do you think it was the IAT sensor connection that was bad not the actually resistor inside the sensor that failed? Sounds like a possibility that the old IAT sensor had a faulty connection to the bike. Is that what you are saying?

 

The ECM receives it's messages from all the sensors in some pretty low voltages typicaly 5v. or less, I don't know what this voltage is, but the ECM like most computers is very sensitive to voltage fluctuations and any drop in voltage will be seen by the ECM as a fault and will respond acordingly changing it's signals to everything else and affecting things such as timing and mixture so it's entirely possible but not certain that a corroded or loose connection could have been the cause. Unless you can see physical dammage to a component such as bubbling etc. the first and cheapest things to check are the connections and an ECM may have to relearn the running stats over a few run times after a fault has been corrected. Hope this helps.

 

That is what i was thinking about the ECM relearning stats. Thanks again, Jim T.