How to read timing data by computer

Adjustment procedure for idle ignition timing and oxygen sensor test of Nissan engine.

Precautions before testing: * The engine must reach the normal operating temperature. * Turn off the electrical appliances and loads of the whole vehicle, such as headlights, air conditioners and fog lights. * When the water tank fan is not running, it is necessary to check whether its speed, ignition timing and carbon monoxide value are correct.

Operating Steps: First, determine whether there is a memory fault code stored in the computer. Read the fault code: use the jumper to jump off the "1" and "2" pins on the diagnostic connector for 2-3 seconds, and then remove the jumper. (or turn the variable resistance knob on the side of the computer clockwise to the end. After 2 seconds, turn it counterclockwise to the end and read the fault code. ) At this time, if the 【 Check 】 light on the dashboard flashes 55, the system is normal.

At this time, if the [Check] light on the instrument panel flashes other faults, the fault code should be handled first, and then the engine should be adjusted. To clear the fault code, jump the jumper from the "1" and "2" pins on the diagnostic connector, turn on the ignition switch, wait for more than 15 seconds, then remove the jumper, (or turn the variable resistor on the side of the computer clockwise to the end, wait for more than 15 seconds, and then turn it counterclockwise to the end to clear the fault code. ) Start the engine and confirm that the engine has reached the operating temperature (the thermometer indicates the position close to 1/2).

Keep the engine idling and accelerate to 2000 rpm, and observe whether the [Check] light is on within 2 minutes; If the [Check] light is on, diagnose and maintain the fault code; If the [Check] light goes out, go to the previous step. After lowering the engine to idle speed, step on the accelerator 2-3 times, reaching about 4000 rpm, and then restore the engine to normal idle speed. Using a jumper wire, first connect the "1" and "2" pins of the diagnostic line, and then turn off the ignition switch (engine off). Remove the throttle sensor thread (four-cylinder engine) or remove the air auxiliary valve.