Toyota Repair: failed emissions high no., combustion chamber, chamber temperature

Question
hey mike just a quick question one of you viewers said they failed emissions because of high co. what would cause high nox. on the same car.

Answer
High Nox is from excessive combustion chamber temperature.

The EGR system intoduces exhaust gas into the engine to cool the burn. Exhaust while hot, is still way cooler than the combustion temp, so it dilutes it.

An EGR valve that is innoperable or clogged would cause high NOX

Vehicles with no egr use the air fuel sensor to input the ECU and richen the mix to cool it buy lenthening fuel injection duration.(the lenth of time the injector sprays in milliseconds)
In that case would be a bad a/f or 02 sensor.
Also a bad Thermostat or hot running engine can cause a rise in NOX

Mike