I in this video I am comparing two different cars. A 2000 Lexus RX300 with a wideband O2 sensor and a 2004 Dodge Neon with a narrow band O2 sensor. I created a no fuel misfire and an ignition misfire on both systems. I am NOT teaching wideband/narrow band O2 operation here, just fuel trim reaction to a misfire. Finally, there is another variable to misfire diagnosis using the oxygen sensor and fuel trim and it has to do with the oxygen sensor itself. Does an O2 sensor actually sense oxygen or fuel? Another question to ask yourself is, does unburned fuel in the exhaust affect the oxygen sensor's signal? The answer to this is absolutely yes! You can see it in this video and my explanation of volume of oxygen in the cylinder is incorrect. The reason there was a difference between the no fuel misfire and ignition misfire was because of the fuel leftover in the exhaust.

Here is a video from my premium channel I've titled "the tomato sensor"

Engine Performance Diagnostics chapters 4 and 5

symptoms 50

  • scan tool

end faq

{accordionfaq faqid=accordion15 faqclass="dotluvfaq help2 aligncenter headerbackground headerborder contentbackground contentborder round7" active=item0}


(Chapters 4 and 5) Fuel Trim and Oxygen Sensor Testing

Related videos:

the "tomato sensor:


fuel trim:


end faq

{accordionfaq faqid=accordion3 faqclass="darkhivefaq defaulticon headerbackground headerborder contentbackground contentborder round5" active=item0}

For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium. There is a 14 day free trial.

On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!