Engine Performance (A8)Pregunta 97 de 120
Technician A says a rich air-fuel mixture can raise tailpipe CO and HC. Technician B says the oxygen sensor helps the PCM keep the mixture near stoichiometric. Who is correct?
a.Technician A only
b.Technician B only
c.Both A and B
d.Neither A nor B
Explicación
A rich mixture leaves excess fuel that raises carbon monoxide and hydrocarbons, and the oxygen sensor feedback lets the PCM hold the mixture near the ideal ratio. Both technicians are correct. A lazy sensor degrades fuel control and emissions.
Practica las 120 preguntas gratis — sin registro.
Preguntas relacionadas de este tema
- A diagnostic trouble code (DTC) of P0301 indicates:
- Technician A says a vacuum leak causes a rich condition. Technician B says a vacuum leak adds unmetered air and causes a lean condition, especially at idle. Who is correct?
- Technician A says a positive long-term fuel trim of +20 percent means the PCM is adding fuel to correct a lean condition. Technician B says positive trim means the engine is running rich. Who is correct?
- Technician A says the MAF sensor measures the mass of air entering the engine so the PCM can meter fuel. Technician B says a dirty MAF can cause hesitation and fuel-trim errors. Who is correct?
- A P0420 code (catalyst efficiency below threshold) most often indicates:
- In a modern coil-on-plug ignition system, each coil:
Última revisión: · proceso editorial
Equipo Editorial de PrepPass · Verificado con ASE Automobile Certification Series (A1–A8) · Cómo revisamos