Mechanical Inspection: Compression
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 1991 Pontiac Sunbird, 1991 Pontiac Grand Prix, 1991 Pontiac Grand Am, 1991 Pontiac Firebird, and 1991 Pontiac Bonneville. 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. For complete compression specifications, refer to SPECIFICATIONS - 4-CYL article (for 4 cylinder models), or refer to SPECIFICATIONS - V6 article (for 6 cyl models) and to SPECIFICATIONS - V8 article (for 8 cylinder models).
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.