Does a faulty O2 light affect peak engine performance?
The fuel management system has an oxygen sensor.Unburned oxygen is monitored in the exhaust.The PCM uses this information to determine if the fuel mixture is rich or lean.To provide the best performance, fuel economy and emissions, the PCM has to constantly adjust the fuel mixture while the engine is running.By looking at the signal from the O2 sensor, it can increase or decrease the on-time of the fuel injectors to control fuel delivery.
The O2 sensors in most late-model vehicles have an internal heater that warms them up when the engine starts.Older, first-generation O2 sensors took a long time to reach operating temperature, which increased cold-start emissions.
The O2 sensor will produce a voltage signal that can range from a few tenths of a watt to a full watt.When there isn't much unburned oxygen in the exhaust, the sensor will generate a small amount of power.The signal is read as a "rich" signal and shortens the duration of the fuel injection pulse to reduce fuel delivery.
The O2 sensor will produce a low-voltage signal when there is a lot of unburned oxygen in the exhaust.A "lean" signal is a signal that increases the duration of the injector pulse and adds fuel to enrich the fuel mixture.The titania-type O2 sensor is slightly different.This type of sensor is used in older Nissan and Jeep vehicles.
The design of O2 sensors has changed.The ceramic thimble-shaped element has been replaced by a flat strip ceramic "planar"-style sensor element.
The basic operating principle is still the same, but the new design is smaller, more robust and reaches operating temperature faster.It is not possible to see the difference from the outside because the tip of the sensor is covered with a metal shroud.
The introduction of wideband O2 sensors is one of the changes.This type of O2 sensor also uses a flat strip ceramic element inside, but it has extra internal circuitry that allows the sensor to measure the exhaust air/fuel ratio with a much higher degree of precision.The O2 sensor can tell the PCM the exact air/fuel ratio, not just a gross rich or lean indication.Vehicles began using oxygen sensors to monitor the operation of the catalytic converter in 1996.After the exhaust has reacted with the catalyst, an O2 sensor is placed behind the converter to monitor oxygen levels.If the operating efficiency of the converter drops below a certain threshold that might cause an increase in emissions, it sets a diagnostic trouble code and turns on the check engine light.
O2 sensors with a limited service life may need to be replaced for preventative maintenance.O2 sensors on 1996 and newer vehicles do not have to be replaced if they have been damaged or contaminated.
O2 sensors can become slow to respond to changes in exhaust oxygen levels when they get old.A drop in fuel economy and higher exhaust emissions are typical symptoms.
A bad O2 sensor shouldn't affect engine starting, cause a misfire, or cause engine stalling.The engine will run rich if the O2 sensor is sluggish.
O2 sensors can be damaged by silicates if an engine has an internal coolant leak and the cooling system has a conventional antifreeze.
The O2 sensor can be contaminated if the engine has an oil consumption problem.
If the O2 sensor fails or stops producing a signal due to an internal failure or a wiring fault, the code will usually be P01.30 to P0147
The codes can be read with a scanning tool.Codes that may seem to indicate a bad O2 sensor are often set by other engine problems.
A lean code means the O2 sensor is reading lean all the time.The real problem may not be a bad O2 sensor, but an engine vacuum leak, low fuel pressure or dirty fuel injectors that are causing the engine to run lean.This type of code may be set by an engine failure, a leaking exhaust valve, or a leak in the exhaust manifold gasket.
If an O2 sensor has failed and needs to be replaced, some aftermarket replacements need to splicing the sensor wires.This type of O2 sensor has fewer part numbers.
Others come with the same style and are easier to install, but require more part numbers.
What causes O2 sensors to fail?O2 sensors slow down as they age.Until the sensor has more than 75,000 miles on it, this isn't a factor.Contamination is the most likely cause of an O2 sensor failing.
There are a number of sources that can cause an O2 sensor to fail.The silicates can pass if the engine has an internal leak due to a crack in the combustion chamber or a leaking head gasket.
Anti-wear ingredients are found in ordinary motor oil.The amount of zinc and phosphorus in motor oil has been reduced to reduce the risk of O2 sensor contamination.
Every engine uses a small amount of oil and it can add up.When the valve guides, rings and cylinders start to wear, oil consumption goes up.In a high-mileage engine that is burning oil, phosphorus and zinc, there can be a problem with the O2 sensors.
The O2 sensors need to be replaced if they are malfunctioning.Replacing the O2 sensors will not restore the fuel feedback control system.The new O2 sensors will suffer the same fate if oil burning is not stopped.There is no difference for a bad catalytic converter and a good one.