Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1991 Jaguar XJ6 BaseFACTORY OEM SERVICE PROCEDURE
Mechanical Inspection: Compression
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.
WARNING:
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 | ||||||
| XJS | 11.5:1 | |||||
| XJ6 | 9.6:1 | |||||
| Compression Pressure | ||||||
| XJS (1) | 200-220 psi (14.1-15.5 kg/cm2 ) | |||||
| XJ6 (2) | 160-170 psi (11.2-12.0 kg/cm2 ) | |||||
|
||||||
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.