Lucas Constant Energy Ignition System (V8i engine) (Discovery 1)

Preliminary check

Check the condition of the battery terminals and the reliability of the cable connections to them. Check the reliability of the high-voltage wires connection and the absence of a breakdown to ground. All wires must be secured with clips to prevent vibration.

Gap in the distributor sensor

Note: The clearance adjustment is performed at the factory. During operation, adjustment is made only when replacing the sensor.

Measure the gap between the sensor core and each tooth of the timing wheel. The gap should be within 0.2 - 0.35 mm. Measurements should be taken with a non-magnetic feeler gauge.

Test #1

Spark formation

Remove the central high-voltage wire (from the ignition coil) from the distributor cap. Holding the wire tip approximately 6 mm from the cylinder block (use insulated pliers). Turn the engine over with the starter. If there is a regular spark discharge, proceed to test 6. If there is no spark formation, proceed to test 2.

Test #2

Low voltage line

Turn on the ignition (do not start the engine).

a) Measure voltages V1 - V4 (see picture), record the voltmeter readings.

b) Compare the readings with the list below

• V 1 is greater than 12 V
• V2 is one volt lower than V1
• V3 is one volt lower than V1
• V 4 0 - 0.1 V

c) If everything is normal, then proceed to test 3.

d) Determine the fault according to the table in the "fault assumption" column.

d) If the ignition coil or amplifier may be faulty, disconnect the low-voltage wire from the coil and repeat the V3 voltage measurement. If the readings remain incorrect, replace the coil. If the voltage is normal, check the low-voltage wire and, if it is normal, replace the amplifier.

e) If the engine does not start, proceed to test 3.

1	2	3	4	assumption of a malfunction
N	-	-	-	the battery is dead
-	N	N	-	ignition switch and/or wiring
-	-	N	-	ignition coil or amplifier
-	-	-	IN	amplifier grounding

[The original article can be found here: www.LRman.ru]

• H - low voltage
• B - high voltage

Test #3

Amplifier

Connect a voltmeter to the battery "+" and the low voltage terminal of the ignition coil. The voltage should be zero.



Turn on the ignition: the voltage should be zero.

Turn the engine over with the starter. Voltage should appear: if yes, go to test 5, if not, go to test 4.

Test #4

Checking the sensor winding

Remove the amplifier.

Measure the resistance of the distributor sensor winding. Normally, the resistance should be 2-5 kOhm. If the resistance is normal, replace the amplifier.

If the engine still does not start, proceed to test 5. After replacing the distributor sensor, proceed to test 5.

Test #5

Ignition coil

Remove the central high-voltage wire between the coil and the distributor. Install a high voltage test lead onto the coil. Holding the wire with insulated pliers 6 mm from the engine block, crank the engine with the starter. If there is no spark or the charging power is low, replace the coil and repeat the test. If spark formation is normal, repeat the test with the original wire. If there is sparking, proceed to test 6; if not, replace the high-voltage wire. If the engine does not start after replacement, proceed to test 6.

Test #6

Distributor rotor

Remove the distributor cap. Remove the high voltage wire from the cover. Hold the wire tip 3 mm above the rotor electrode and crank the engine with the starter.

If a spark jumps between the rotor and the wire, proceed to test 7; if there is no spark, replace the rotor. If the engine does not start after replacement, proceed to test 7.

Test #7

Visual inspection

1. The distributor cap is clean, dry, without cracks or signs of breakdown.

2. The sensor core is clean, dry, and free of any signs of breakdown.

3. Insulation of high-voltage wires - no cracks or abrasions.

4. Conductivity of high-voltage wires - must be.

5. Spark plugs are clean, dry, with the gap between the electrons adjusted.