Cylinder Balance Diagnostic Test Mode (SEFI Only) Description

The purpose of the cylinder balance test is to aid the technician in finding a weak or non contributing cylinder.
Once the test is entered, engine idle speed is stabilized through the Idle Air Control (IAC) duty cycle. Engine rpm is measured and stored for comparison with the other readings received later in the testing. Then fuel is shut OFF to cylinder 4, 6 or 8, depending on the engine. After engine speed stabilizes, the rpm is measured and stored. The injector is turned ON and the process is repeated for each cylinder. The maximum rpm drop is selected from the table of drops for each cylinder. This maximum drop is now multiplied by a calibrated precentage. The resulting number (rpm) is now used as the minimum rpm that each cylinder must have dropped to pass the test.
(Example: 150 rpm x 65% = 98 rpm).