Table of contents: Low voltage circuit ↓ High voltage circuit ↓
1. There are two obvious signs of ignition failure. The engine does not start or fires, or it is difficult to start and does not run normally. If the engine does not start, the failure may be in the low-voltage or high-voltage circuit. However, if the engine starts but does not run normally, the failure is most likely in the high-voltage circuit.
2. If the engine will not start due to moisture on the high-tension wires or in the distributor cap, a dispersant can be used to absorb the moisture.
Low voltage circuit
3. See the procedures given in Chapters 6, 8 or 10.
High voltage circuit
4. Damage in the high voltage circuit will be limited to the spark plugs, high tension wires, distributor cap, distributor rotor or ignition coil.
5. Disconnect the spark plug high tension lead and connect it to a spare spark plug securely clamped to the cylinder head. The spare spark plug must be in good condition and can be grounded to the cylinder head or a suitable grounding point if necessary. It is not advisable to have the high tension leads too close to the head as this may damage the electronic ignition components.
6. Crank the engine quickly with the starter to check for a good spark at the spark plug. Do not repeat this procedure on models equipped with a catalytic converter.
7. Connect the high tension wire and repeat the test on the remaining spark plugs.
8. If there is good spark on all cylinders, remove the spark plugs and clean or replace them.
9. If there is no spark at all, check the high-tension wires. Also check the ignition coil and the distributor cap.
10. Remove the cover of the breaker-distributor, check the wear of the surface between the high-voltage parts (internal and external). Replace the cover if necessary.
11. Check the distributor rotor in the same way. Note that the distributor rotor on the 7A engine is attached to the drive shaft and cannot be replaced.
12. Check the carbon brush in the distributor cover.
13. Clean off any carbon deposits in the distributor cap and on the distributor rotor segments, but do not remove any metal.
14. Install the distributor runner and the breaker-distributor cover, connect the high-voltage wires.