Oxygen Sensors on Vehicle
Make Nissan, Model Skyline Year 2000
I Located Oxygen Sensor, it was on the right hand side extruding form the exhaust manifold, close to the firewall
This 02 sensor had 3 wires.
The colours for each of the wires at the sensor side of the connector (not the ECU side of the connector). Usually a black or blue wire will be the O2 sensor signal, Grey may be the sensor ground. Heater power and ground are often white.
Colour Use or Purpose Black - Signal out
This is a switching type sensor. Another type is the broadband sensor.
Back probe the Oxygen Signal Wire with a pin and connect to an oscilloscope
Engine warm up and enter closed loop so you see a normal cycling pattern. You may have to hold the rpm about 2500 for half a minute to go into closed loop if it’s cold but my engine is warm and already in closed loop from driving so I could see a normal cycling pattern (from red up to green then quickly back to green low then back to red)
The voltage went as high as 0.83V for 10ms
The average voltage at a guess was 0.55V
The signal has 5 to10 “Cross Counts” in 10 seconds. (One cross count is when it goes from high to low, or from low to high.)
The signal is cycling normally.
The engine is warm and in closed loop so you see a normal cycling pattern.
The graph below is of Oxygen Signal pattern at idle rpm
4.2 How high does the voltage go? 0.6V
4.3 How low does the voltage go? 0.4V
The average voltage is 5.5V
The signal has 8 “Cross Counts 10 seconds
The signal is cycling normally.
5.0 Make this Oxygen Sensor go rich by accelerating once or twice. (The fuel system should normally make the system go rich when you do a sudden acceleration.) Push on the accelerator quickly. The signal should go over 0.85V.
5.2 How high does the Oxygen sensor voltage go? 0.84V
6.0 I made this Oxygen Sensor go lean by doing a sudden deceleration. Gently run the rpm up to about 3,000, and let the RPM drop suddenly. The fuel system made the system go lean on deceleration. The signal went below 0.2V.
The Oxygen sensor voltage goes as low as 0.038V
The signal is going low normally
7.0 Measure the Response Time of the sensor. You want to know that the sensor can respond quickly to changes in the exhaust gas. The best way is to do a sudden acceleration, freeze the pattern, and measure how long it took the sensor to go from lean to rich.
7.1 Freeze your pattern as it goes suddenly rich from a lean condition and draw it into the graph below: Normally you want the voltage to go from below 0.2V to above 0.8V. In less than 100 ms. Note the voltage and time per division or scale next to the graph.
7.2 Measure how long the sensor took to go from lean to rich. Use the cursers on the scope if necessary. Record how long the sensor took here: 200ms
8.0 Discuss how a normal Zirconium oxygen sensor works: draw a picture below to help show how it works?
This Oxygen Sensor is Good as it cycles to the correct voltages of 0.85 down to 0.2 and averages at 0.55 when at idle. It functions well, it can accurately tell the ECU how rich or lean the exhaust is.
Engine warm up and enter closed loop so you see a normal cycling pattern. You may have to hold the rpm about 2500 for half a minute to go into closed loop if it’s cold but my engine is warm and already in closed loop from driving so I could see a normal cycling pattern (from red up to green then quickly back to green low then back to red)
5.0 Make this Oxygen Sensor go rich by accelerating once or twice. (The fuel system should normally make the system go rich when you do a sudden acceleration.) Push on the accelerator quickly. The signal should go over 0.85V.
6.0 I made this Oxygen Sensor go lean by doing a sudden deceleration. Gently run the rpm up to about 3,000, and let the RPM drop suddenly. The fuel system made the system go lean on deceleration. The signal went below 0.2V.
7.1 Freeze your pattern as it goes suddenly rich from a lean condition and draw it into the graph below: Normally you want the voltage to go from below 0.2V to above 0.8V. In less than 100 ms. Note the voltage and time per division or scale next to the graph.