What is a Compression Test?If your engine loses compression on one or multiple cylinders, problems will follow. From a misfire to a massive reduction in power, there are some severe and complicated problems that can arise. A compression test is by far one of the most basic engine test procedures and starting point to understand exactly what your engine is doing, and where the problem may be.The premise of a compression test is to test each cylinder to see in measured PSI exactly how much compression that particular cylinder is producing. From a single piston lawn mower engine, to a diesel or V8 engine, the process is entirely the same – measure what the cylinder is producing in PSI. Understanding a compression test procedure is also understanding what you are trying to achieve, and that is consistency between the numbers of each cylinder, and looking for the outlier, or outliers. If you measure the tire pressure of 4 tires on your car, and the measurement of three of them is 32PSI, but...
