ABSTRACT
This chapter presents case studies which are all real jobs that were written up and sent to the author by the technician who did the fault-finding. The conventional or classic tool for assessing the state of an engine cylinder and piston is a compression gauge. It is designed to measure the compression or peak pressure in the cylinder obtained while cranking the engine. The measurement is a complex value and depends on losses through cylinder leakage, the compression ratio, the valve timing, the cranking speed and the state of the intake and exhaust ports or manifold. The Px script can distinguish cylinder leakage from low compression ratio because it independently calculates gas losses and the compression value. Normal pressure or gas loss for an engine in good condition is in the 10–18 percent range. A loss of more than 20 percent could indicate excessive leakage in a cylinder.
