Prerequisites for rotary cylinder pressure detection

(1) The battery is fully charged. Loss of battery power can cause engine speed to be too low.

(2) The engine coolant temperature is normal. The engine coolant temperature is at normal operating temperature (above 80 °C). The cold car and the hot car combustion chamber have different sealing degrees, so the measured values ​​are different.

(3) Remove the air filter element.

(4) Remove all spark plugs. The cylinder pressure of each cylinder is measured cylinder by cylinder. Without disassembling the spark plug, the measured cylinder pressure will be higher than the actual cylinder pressure. If one is to be measured, the higher the cylinder pressure will be measured.

(5) For the EFI car, the oil pump insurance or other relay insurance must be removed and tested again, otherwise it will lead to “draining cylinder” and low cylinder pressure.

(6) The test hole must not leak. Before the measurement, tighten the hose joint of the cylinder pressure gauge and the spark plug hole, and do not leak. Before each measurement, the cylinder pressure gauge should be returned to zero. When the crankshaft is rotated by the starter, the accelerator pedal is fully depressed to the end, and the throttle valve is throttled. Maintain 3 to 5 s in the fully open position (engine speed is above 2500 r/min, engine speed is too low, cylinder pressure will be too low).

(7) Calculation of the rotary cylinder pressure. Each cylinder is tested twice, with the average being the cylinder pressure of the cylinder.