AFR running extra rich at WOT? - Toyota Yaris Forums

eTiMaGo · 03-06-2007, 10:04 PM

I'm not sure if anyone here has an air-fuel ratio sensor on their car, but hopefully someone knowledgeable can help me with this.

Normally the ratio flicks between rich and lean, from what I understand this is normal, just the ECU's way of improving the catalyser's performance.

But, I was on the highway the other day, in 5th gear, pedal to the metal, crawling along the traffic (

), and I was checking my AFR gauge, which was stuck pretty high, at a little under 12:1. When this is the case there is also a slight sulphurous smell pervading the cabin.

So, as my ECU has not been touched, is this rich ratio normal in these situations? From my understanding it should be running maybe a little lean in order to extract maximum power, right? Or could this be a result of a faulty/dirty MAF sensor, or just my AFR gauge being stupid?

03-06-2007, 10:04 PM	#1
eTiMaGo vroom vroom View User's Garage Drives: lil red 5-door Join Date: Sep 2006 Location: Bangkok, Thailand Posts: 7,744	AFR running extra rich at WOT? I'm not sure if anyone here has an air-fuel ratio sensor on their car, but hopefully someone knowledgeable can help me with this. Normally the ratio flicks between rich and lean, from what I understand this is normal, just the ECU's way of improving the catalyser's performance. But, I was on the highway the other day, in 5th gear, pedal to the metal, crawling along the traffic (), and I was checking my AFR gauge, which was stuck pretty high, at a little under 12:1. When this is the case there is also a slight sulphurous smell pervading the cabin. So, as my ECU has not been touched, is this rich ratio normal in these situations? From my understanding it should be running maybe a little lean in order to extract maximum power, right? Or could this be a result of a faulty/dirty MAF sensor, or just my AFR gauge being stupid? __________________ The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson Bye bye 1NZ...