The automated cylinder performance test is the most thorough test of cylinder performance (versus the single-
cylinder cutout test, which tests the performance if individual cylinders only). The service tool must be attached to an electronic control module (ECM) to perform the test. Follow the steps outlined in Preparing to Run the
Automated Cylinder Performance test, to make sure the best possible outcome is achieved.
This test is automated in the sense that, once the test is started, the service tool controls what cylinders are
disabled or enabled, what ECM values are recorded, and what information displays as a result of the test. Once the test is finished, follow the steps outlined in the After Running the Automated Cylinder Performance Test to make sure the engine returns to its original state.
This test will produce a Pass or Fail message for each cylinder. Its percent contribution value is also displayed.
Preparing to Run the Automated Cylinder Performance Test:
Before performing the test, make sure the following are completed:
• Clear the areas around the engine and the fan, and make sure the exhaust is vented correctly.
• Operate the engine until the coolant temperature is a minimum of 76.7°C [170°F).
• Shut off the engine.
• Lock the fan clutch in the ON position for continuous operation.
• Shut off the air conditioning.
• Disengage any devices that can cause the load on the engine to vary.
• With the vehicle stationary, start the engine and let it idle.
• Start the test using INSITETM electronic service tool.
Refer to the INSITETM electronic service tool user’s manual for detailed automated cylinder performance test
instructions.
After Running the Automated Cylinder Performance Test:
It is normal for the engine rpm to vary during the test, but if the engine rpm goes to high idle for more than 5 seconds at a time, shut off the engine.
Once the test is complete, make sure to complete the following:
• Shut off the engine.
• Return the fan to normal operation, if necessary.
• Perform the suggested repairs that resulted from the test.
• Return any disengaged devices to their normal mode of operation.
