Mechanical Inspection: Compression
WARNING: This page is about a different car, the 1994 Mercury Tracer, 1994 Mercury Topaz, 1994 Ford Tempo, 1994 Ford Probe, and 1994 Ford Escort. However, it is still accessible from the selected car via links, so may be relevant.
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions. Compression pressures are considered within specification if the lowest reading cylinder is within 75 percent of the highest reading cylinder.
WARNING:
DO NOT
use ignition switch during compression tests on fuel injected vehicles. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking mode, which can create a fire hazard or contaminate the engine's oiling system.