General Overview
Ignition system with tachometer and timing service instrument socket- 1985Operation
This breakerless ignition system is equipped with a Hall sensor.
When the ignition switch is in the start or drive position, +15 is supplied to ignition coil 5 and amplifier 146.
The amplifier receives ignition pulses via a shielded cable from the Hall sensor in ignition distributor 6. The frequency of the pulses is equivalent to the engine speed.
The pulses are amplified and adjusted in amplifier 146. A high-tension pulse is produced in the secondary winding each time a pulse breaks the primary circuit of the ignition coil. The high-tension pulse is then supplied to the corresponding spark plug via the distributor.
Tachometer 110 is supplied across fuse 22. The control pulses required for displaying the engine speed are supplied from terminal 1 of the amplifier, via timing service instrument socket 73.
Timing service instrument (TSI) socket 73 is intended for a special ignition service instrument and has the following terminals:
1. Positive supply direct from battery 1
2. Earth
3. Solenoid (terminal 50) on starter motor 4
4. Positive supply (+15) from the ignition switch when the latter is in the start or drive position
5. Ignition pulses from amplifier 146
6. Not used
Fault-tracing hints
The ignition system will be energised when the ignition switch is in the drive position.
1. Check that terminal 15 on the ignition coil and terminal 4 on timing service instrument socket 73 are live.
2. check that terminal 4 on amplifier 146 is live.
3. Tachometer: check fuse 22 first and check that the supply to it is live. check that terminal 3 on the circuit board for tachometer 110 is live, and that ignition pulses are being supplied from the amplifier.
4. Check all connectors, cable harnesses and earth connections.