Initial Inspection and Diagnostic Overview
Preliminary checksInspect battery cables and connections to ensure they are clean and tight. Check electrical condition of battery.
Inspect all L.T. (Low Tension) connections, ensure they are clean and tight. Check H.T.(High Tension) Leads are correctly positioned and not shorting to ground against any engine components. Wiring harness and individual cables should be firmly fastened to prevent chaffing.
Pick-up Air Gap
Check air gap between pick-up limb and reluctor teeth is 0.20 - 0.35 mm, using a non-ferrous gauge.
NOTE: Air gap is set initially at factory and will only require adjusting it tampered with or when pick-up module is replaced.
Test 1: High Tension Spark:
Remove coil/distributor H.T. lead from distributor cover and hold approximately 6 mm from engine block, using suitable insulated pliers. Switch ignition 'On' and operate starter.
Regular sparking indicates fault in H.T. distribution, plugs, timing or fuelling, proceed to Test 6. If no spark or weak spark occurs proceed to Test 2.
Test 2: Low Tension Voltage:
Switch Ignition 'On' - Engine Not Running.
(a) Connect voltmeter to points in circuit indicated by V1 to V4 and make a note of voltage readings.
(b) Compare voltages obtained with specified values listed below:
Expected readings
V1 More than 12 volts.
V2 1 volt maximum below volts at V1.
V3 1 volt maximum below volts at V1.
V4 0 volt-0.1 volt.
(c) If all readings are correct proceed to Test 3.
(d) Check incorrect reading(s) with chart to identify area of possible faults, i.e. faults listed under heading SUSPECT and rectify.
(e) If coil and amplifier is suspected, disconnect L.T. lead at coil, repeat V3. If voltage is still incorrect, fit new coil. If voltage is now correct, check L.T. lead, if satisfactory fit new amplifier.
(f) If engine will not start proceed to Test 3.
Voltage Chart:
Key
* Expected Voltage.
H Voltage higher than expected.
L Voltage lower than expected.
Test 3: Amplifier Switching:
Connect voltmeter between battery positive (+ve) terminal and H.T. coil negative (-ve) terminal. Voltmeter should register 0 volts.
Switch ignition 'On', voltmeter should still register 0 volts.
Crank engine, voltmeter reading should increase when cranking, in which case proceed to Test 5.
If no increase in voltage during cranking proceed to Test 4.
Test 4: Pick-up Coil Resistance:
Remove Amplifier.
Connect ohmmeter leads to two pick-up terminals in body of distributor.
The ohmmeter should register between 2 k and 5 k ohm if pick-up is satisfactory. If ohmmeter reading is correct, check all connections between pick-up and amplifier, if satisfactory, fit new amplifier. If engine still does not start carry out Test 5.
Change pick-up if ohmmeter reading is incorrect. If engine still does not start proceed to Test 5.
Test 5: Coil,High Tension Spark:
Remove existing coil/distributor H.T. lead and fit test H.T. lead to coil tower. Using suitable insulated pliers, hold free end about 6 mm from engine block and crank engine. There should be good H.T. sparking.
If weak or no sparking, fit new coil, repeat test.
H.T. sparking good, repeat test with original H.T. lead. If sparking is good carry out Test 6.
If weak or no sparking, fit new H.T. lead, if engine will not start carry out Test 6.
Test 6: Rotor Arm:
Remove distributor cover. Disconnect coil H.T. lead from cover using insulated pliers hold about 3 mm above rotor arm electrode and crank the engine.
There should be no H.T. sparking between rotor and H.T. lead. If satisfactory carry out Test 7.
If H.T. sparking occurs, an earth fault on rotor arm is indicated. Fit new rotor arm. If engine will not start carry out Test 7.
TEST 7: Visual and H.T. cable checks.
Examine: Should be:
1. Distributor Cover Clean, dry, no tracking marks
2. Coil Top Clean, dry,no tracking marks.
3. H.T. Cable Insulation Must not be cracked or chafed.
4. H .T. Cable Continuity Must not be open circuit
5. Sparking Plugs Clean, dry, and set to correct gap
NOTE:
1 Reluctor Must not foul pick-up or leads
2 Rotor and Insulation Cover Must not be cracked or show signs of tracking marks