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Rover Rover 600 Repair Manual - Volumes 1 and 2 - 2nd Edition18 · Electrical
18 · Electrical

Ignition Timing Control

Make
Rover
Model
600 Rover 600 Repair Manual - Volumes 1 and 2 - 2nd Edition
Section
Repairs › Ignition Timing Control
ElectricalIgnition Timing Control · page 1 of 3

Ignition Timing Control

The programmed ignition (PGM – IG) used in this engine provides optimum control of ignition timing. A microcomputer determines the timing in response to engine speed and manifold vacuum. The input signals are transmitted by the TDC/crankshaft position (CKP)/cylinder position (CYP) sensor, throttle position (TP) sensor, engine coolant temperature (ECT) sensor, and MAP sensor. This system, which is not dependent on a governor or vacuum diaphragm, is capable of setting lead angles with complicated characteristics which cannot be provided by conventional governors or diaphragms.

Block diagram showing inputs (Battery voltage, TDC/CKP/CYP sensor, MAP sensor, Engine coolant temperature (ECT) sensor) feeding into Engine control module (ECM), which outputs to Ignition control module, Ignition coil, Distributor, and Spark plugs.

Basic Control

The engine control module (ECM) has stored within it the optimum basic ignition timing for operating conditions based upon engine speed and intake manifold vacuum. With compensating signals from sensors, the system determines optimum ignition timing and duration for ambient conditions and sends voltage pulse to the ICM.

Compensation of ignition timing

Compensation ItemRelated sensor and InformationDescription
IdlingCrank/Cylinder sensor
MAP sensor		Ignition timing is controlled to the target speed with compensation according to the idling speed.
Compensation at warm – upECT SensorLag angle is adjusted according to warm – up conditions to bring about a good balance between operating performance and exhaust emissions.
ECT compensationECT sensorCompensation for lead angle at low engine coolant temperature, and lag angle at high engine coolant temperature.

Control at Start:

Ignition timing is fixed at 7° BTDC for cranking. The cranking is detected by the TDC sensor (cranking rpm) and starter signal.

Parts & tools for this job For Rover 600

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