Cylinder Balance Test

CYLINDER BALANCE TEST

Purpose

- The purpose of the cylinder balance test is to find weak or non-contributing cylinders. In this test, the high-tension leads are disconnected one by one to shut off the ignition in each cylinder while the engine is running. The engine speed drop caused by this operation is measured and compared with each other, and the cylinder condition is judged. If all the engine speed decrease amounts are almost the same with any of the cylinder inoperative, there will be no weak or non-contributing cylinder. Engine speed different from others indicates that the corresponding cylinder is considered to be weak or non-contributing.

WARNING:
- High-voltage in ignition system can cause strong electrical shock. Avoid direct contact to the vehicle body during the cylinder balance test.
- High-voltage spark will negatively effect the engine control. To prevent this, ground the high-tension lead and keep away from sensors and harnesses.
- Cylinder balance test can overheat and damage the three way catalytic converter.

NOTE: Diagnostic trouble codes (No. P0300, P0301, P0302, P0303, and P0304) will be stored in the PCM memory during the cylinder balance test. Carry out "After Repair Procedure" and erase these codes after this test.


Procedure

1. Connect the SSTs (NGS tester) to the data link connector-2 and select the PID/DATA MONITOR AND RECORD function.




2. Select the "RPM" on the NGS tester display.
3. Start the engine and let it idle.
4. Disconnect each high-tension lead and measure the engine speed.
5. Compare the engine speed decrease amounts.