LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Saab >> 1991 >> 900 SPG >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Preliminary Inspection & Adjustments >> Mechanical Inspection >> Compression
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Mechanical Inspection: Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer instruction manual for specific instructions.

CAUTION: Use a remote starter to crank engine during compression test, NOT the ignition switch. The fuel injectors on many fuel injected models are triggered during the cranking mode. This could cause a fire hazard, flooding, crankcase contamination, hydrostatic lock, or lubrication to be washed off of cylinder walls.

Check engine compression at normal operating temperature with all spark plugs removed. To prevent damage to catalytic converter, make tests quickly and only when necessary.

ENGINE COMPRESSION (1)

Application Specification
Compression Ratio
900 Non-Turbo 10.1:1
900 Turbo 9.0:1
9000 Non-Turbo 10.1:1
9000 Turbo 8.5:1
(1)
Compression pressure is not specified by manufacturer.