A quick way to check for low cylinder compression.
A engine with uneven compression or loss of compression in one or more cylinders will not crank smooth. You will notice what sounds like
a jump in the RPM as it cranks. Now, if you have this condition it is an indication of a serious problem that will require
more work to pinpoint and repair.
- Disable the ignition system by removing the coil wire. (this may not be possible on newer distributorless ignition systems).
- Turn the ignition key to the start position to crank the engine.
- Listen closely for a "bump" in the RPM at the engine is turning.
Article Date: 06/23/2006