The oxygen sensors (also called O2 sensors) are one of the most important elements of the modern fuel injection systems. A finely tuned fuel injection system with an oxygen sensor can maintain an air/fuel ratio within a close tolerance of .02 percent. Keeping the engine at the stoichiometric ratio (14.7:1 air/fuel ratio) helps the engine generate the most power with the least amount of emissions.

The oxygen sensors are located in the exhaust system of the engine, and they sense the oxygen content of the exhaust gases. There are two on this Mercedes Benz M104 engine: one on each side of the catalytic converter. The sensor located just in front of the catalytic converter measures the mixture of the exhaust gas exiting the engine. The sensor located after the catalytic converter is used to measure the performance of the converter by comparing the O2 levels before and after. (Upstream is the same as precatalyst, before the catalytic converter. Downstream is post-catalyst or behind the catalytic converter.) The amount of oxygen in the exhaust varies according to the air/fuel ratio of the fuel injection system. The oxygen sensor produces a small voltage signal that is interpreted by the electronic control unit (ECU) of the fuel injection system. The ECU makes constant adjustments in fuel delivery according to the signal generated by the oxygen sensor in order to maintain the optimum air/fuel ratio.

There are a few signs that your oxygen sensor may be failing. In general, it is difficult to diagnose problems with the sensor, unless all of the other components in the fuel injection system have been checked and determined to be operating correctly. Some of the symptoms of a failed oxygen sensor system are:

Irregular idle during warm-up
Irregular idle with warm engine
Engine will not accelerate and backfires
Poor engine performance
Fuel consumption is high
Driving performance is weak
CO concentration at idle is too high or too low
Check Engine Lamp is illuminated

In general, if the oxygen sensor is not working, the car will be running very poorly, and will also be outputting a lot of harmful emissions. The cars computer will usually give a warning signal that lights up the Check Engine Lamp if the signal received by the computer is out of its normal range. Sometimes the computer may output an error code stating that the oxygen sensor is reading out of range, when in reality the values registered by the O2 sensor are accurate because there is something else wrong with the fuel injection system. Prior to replacing the oxygen sensors, make sure there are no other codes being recorded that may affect the O2 sensor readings.

Read the Full Article: https://www.pelicanparts.com/techarticles/Mercedes-Benz/12-FUEL-Oxygen_Sensor_Replacement/12-FUEL-Oxygen_Sensor_Replacement.htm

Time: 1 hour
Tab: $300
Tools: 22mm wrench :https://www.pelicanparts.com/Mercedes-Benz/catalog/tools/wrenches.htm, 22mm crow's-foot wrench, jack stands :https://www.pelicanparts.com/Mercedes-Benz/catalog/Tools/jacks.htm
Applicable Models:
Mercedes-Benz E320 (1996-00)
Mercedes-Benz E420 (1997) :https://www.pelicanparts.com/catalog/SuperCat/W210_catalog.htm
Parts Required: New O2 sensors :https://www.pelicanparts.com/cgi-bin/supertech/catalog.cgi?action=frameset&return-url=/cgi-bin/supertech/catalog.cgi%3Faction%3Dframeback%26page%3D619&catalog-url=https%3A%2F%2Fwww.pelicanparts.com%2Fcatalog%2FSuperCat%2F3782%2FMBZ_3782_ELSENS_pg1.htm%23item1
Hot Tip: take your time with the front sensor
Performance Gain: Car runs better.
Complementary Modification: Replace transmission mount

Hochgeladen am 29.09.2020   Problem melden   Dieses Video bei YouTube   Pelican Parts bei Youtube