LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jaguar >> 1993 >> XJS 2D Convertible, Automatic >> 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 manual for specific instructions. Depressurize fuel system before checking engine compression. See FUEL SYSTEM  below in this article.

CAUTION: DO NOT  use ignition switch during compression tests on fuel injected vehicles. Use a remote starter to crank engine. Fuel injectors are triggered by the ignition switch during cranking mode, which can cause a fire hazard, or contaminate the engine's oiling system.
COMPRESSION SPECIFICATIONS

Application Specification
Compression Ratio 9.5:1
Compression Pressure (1) 160-170 psi (11.2-12.0 kg/cm2 )
Maximum Variation Between Cylinders 10 psi (.70 kg/cm2 )
(1) Minimum cranking speed is 300 RPM.