Ray-CylinderLeakDownTestRay Bohacz is a journalist in the automotive field and author of CarTech’s book “How to tune and win with Demon Carburetion”. He is also a monthly contributor to Hemming’s Muscle Machines magazine. Additionally, Ray writes short articles for the agriculture industry and is featured in a series of videos as the SF (Successful Farming) Engine Man. His videos introduce brief, informative features which apply to both farm and automotive equipment.

Most modern fuel injection systems employ a mass air flow sensor (MAF) that is located between the air filter assembly and the throttle-body.

The MAF measures the air flow into the engine. This data is mainly used by the engine controller (ECU) to determine fuel injector pulse width. The MAF output is also combined in an algorithm with the outputs from the crankshaft and throttle position sensors to determine engine load. This influences both fuel and ignition timing.

The MAF output will skew when coated with air-borne contaminants. This is how to easily restore its accuracy. Watch the video.