The procedure for using a cylinder pressure tester is as follows: First, install the equipment and preheat the vehicle. Then, remove the spark plugs or injectors, open the throttle, and finally start the engine to read the pressure value. The specific operating steps are as follows:
Equipment Installation and Vehicle Warming: Install the cylinder pressure gauge (or pressure sensor) onto the engine, ensuring a secure connection. Start the engine and preheat it to normal operating temperature (usually above 80°C for coolant). This ensures the engine is warm and guarantees accurate test results.
Spark Plug or Injector Removal
Turn off the engine and disconnect the secondary high-voltage wire of the ignition system, ensuring reliable grounding (to avoid the risk of electric shock or fire).
Blow away any foreign objects around the spark plugs with compressed air (to prevent impurities from entering the cylinder), then remove the spark plug from the cylinder being tested (for diesel engines, the injector must also be removed).
If the tester needs to be connected through the spark plug bore, tighten the special threaded fitting or tapered rubber tip onto the spark plug bore; if connected through the injector bore, an adapter is required.
Open the throttle and connect the diagnostic tool.
Manually open the throttle fully (ensuring minimal intake resistance and complete cylinder pressure release).
Insert the conical rubber tip or sensor probe of the cylinder pressure gauge into the spark plug hole (or injector hole), ensuring a good seal to prevent leaks from affecting the data.
Start the engine and read the pressure value.
Depress the clutch (for manual transmission vehicles) and shift the gear to neutral. Start the engine (it is recommended that an assistant operate the starter).
Observe the pressure gauge needle's movement. After the needle stabilizes, read the maximum pressure value (usually requiring 2-3 seconds).
Record the value and then turn off the engine. Repeat the above steps to test the other cylinders, ensuring balanced pressure across all cylinders.
