These manuals will give you the factory specifications for compression, which is usually expressed in PSI (pounds per square inch). They'll also provide instructions on how to properly perform a compression test.
Keep in mind:
* Variations are normal: Even within a given model year, there will be some acceptable variation between cylinders. The manual will specify the allowable difference between the highest and lowest readings.
* Temperature matters: The engine should be at operating temperature for an accurate test.
* Testing procedure is crucial: Properly performing the test (fully charged battery, throttle fully open, etc.) is essential for reliable results.
Without knowing the year of your Jeep Cherokee 2.8L V6, I cannot provide a specific compression range. Always refer to your vehicle's service manual for the correct information.
