NOTE: On Discovery Series I, ignition timing is controlled by Land Rover's Generic Engine Management System (GEMS) through the Engine Control Module (ECM) and is not adjustable. On Discovery Series II and Range Rover, ignition timing is controlled by Bosch Motronic M5.2.1 engine management system through the ECM and is not adjustable. Ignition timing is adjusted for each cylinder based on engine load, speed and temperature, knock control, automatic gearbox shift control and idle speed control. On Range Rover, nominal value for a warm engine at idle is 12° BTDC. Always refer to SERVICE INFORMATION underhood label in engine compartment. If underhood label and lemon-25® specifications differ, always use underhood label specifications.

IGNITION TIMING ⁽¹⁾

Application

Specification

Discovery Series I

⁽²⁾

Discovery Series II

⁽²⁾

Range Rover

12° BTDC

⁽¹⁾	Idle speed and timing are computer controlled and are not adjustable.

⁽²⁾	Information not available from manufacturer.

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.

Safety Warning

Ignition Timing

Use the Manual With the Right Hardware

When to See a Mechanic

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