Cylinder Balance Test - SEFI Engines: Introduction

The cylinder balance test is used to identify a weak or non-contributing cylinder. It is only available for sequential PFI engines. The ECA performs it by disabling the fuel injector on each cylinder, one at a time, and comparing each cylinder's RPM drop.

The test is entered by depressing and releasing the throttle (only a 2-3° throttle angle is required, NOT a wide open throttle) within two minutes after receiving the last code in the Engine Running (KOER) self-test (during the computed timing portion of the test).

After the approximately three-minute test, a code is generated to either identify the specific weak cylinder, indicate there is no problem, or request a retry. See CYLINDER BALANCE TEST SERVICE CODE TABLE .

The test can be repeated for a second or third time by tapping the throttle within two minutes after the code appears from the previous test. Each time, the percentage of allowable variation between cylinders is eased. So by the third pass, only a very weak/dead cylinder should set a code.

The cylinder balance test may still be repeated as many times as desired past three, but all further passes will be done at the level three tolerance.