Mechanical Inspection: Compression
WARNING:
DO NOT use ignition switch during compression tests on fuel injected vehicles. Use a remote starter switch to crank engine. Fuel injectors and fuel pump are activated by ignition switch during cranking mode, which can create a fire hazard or contaminate the engine's oiling system.
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer user manual for specific instructions. Engine compression ratio specification is displayed above engine identification code. Engine identification code is stamped on a cast pad located between cylinders No. 3 and No. 5. See Fig 1.
Start and operate engine until normal engine operating temperature thermostat opens. Remove all spark plugs. Disconnect ignition coil connector. Insert compression gauge, crank engine using a remote starter switch until reading stabilizes. With Wide Open Throttle (WOT) and fully charged battery compression should be approximately 170-180 psi (12.0-12.7 kg/cm2 ).