Attention! Due to the very high voltage generated in the ignition system, the maintenance of its components must be carried out with extreme care. This note applies not only to the main components of the electronic ignition system, but also to all related components, including spark plug wire tips, tachometer and other diagnostic equipment.
1. If the ignition system malfunctions, before proceeding with the diagnosis of the distributor condition, perform the following preliminary checks:
- a) Check the condition of the battery terminal connections and the reliability of the tightening of the clamps for attaching the wire lugs to them;
- b) Check Battery Status (see Checking the condition and replacing the battery), if necessary, replace it;
- c) Check the external condition of the BB wires of the distributor and the ignition coil and the reliability of their fastening to the terminals;
- d) With the appropriate configuration, check the condition of the fusible inserts in the mounting block located in the engine compartment of the vehicle (see chapter Onboard electrical equipment). Replace burned out elements.
2. Check up serviceability of spark formation on spark plugs. If the engine cranks but does not start, disconnect the BB wire from one of the spark plugs and connect it to a special calibrated tester (ask at car accessories stores). Fasten the tester clamp to a bolt or metal bracket of the engine block, thus reliably grounding it to ground (see accompanying illustration). If you don't have a calibrated ignition tester handy, disconnect the wire from the spark plug and, holding it with a pair of pliers with securely insulated handles, pull the rubber tip up the wire and run the terminal to a well-grounded point on the block to a distance of approximately 6.4 mm. When turning the engine between the electrode and the body of the tester / terminal of the BB wire and the ground, a clearly visible spark of bright blue color should jump. Crank the engine while watching the tester terminal or wire - with sufficient voltage applied to the spark plug, an intense bright blue spark should jump between the electrode and the tester housing / wire terminal and the engine block.
- a) If the spark breaks through properly and its intensity is not in doubt, repeat the test for the BB wires of the remaining spark plugs. This check allows you to confirm the serviceability of the cover and the distributor runner, without excluding, however, the possibility of failure of the candles themselves, so turn out the spark plugs and check their condition in accordance with the chapter Current service of this Guide description;
- b) If there is no spark, remove the distributor cap and check its condition, as well as the condition of the slider (see chapter Current service). If there are traces of moisture, carefully wipe the surfaces of the cover and slider with a clean, dry rag, then replace the cover and repeat the spark test;
- c) If the removal of moisture did not lead to a correction of the situation (sparking is still insufficiently intense or absent at all), disconnect the secondary wire of the coil from the distributor cap and connect the ignition tester to it (do not forget to connect the BB wires to all candles). Repeat the above test procedure. Check the condition of the spring and the contact carbon button inside the distributor cap for traces of burnout and mechanical damage. if necessary, replace the distributor cap.
Note. In the absence of an ignition tester at hand, an alternative test of the coil wire is carried out in the same way as in the case of BB wires of spark plugs by bringing the terminal to ground at a distance of about 6.4 mm.
Note. The vehicles covered in this manual are equipped with an ignition coil built into the distributor.
3. If normal sparking occurs this time, then the cause of the failure lies in the malfunction of the distributor cap, its runner or the corresponding spark plug wires (see chapter Current service).
4. In the absence of sparking and at this stage, you should proceed to checking the contact connections of the primary circuit of the ignition coil - evaluate the condition and reliability of fastening the terminals. Check the correctness of the primary voltage supply to the coil from the ignition switch / lock, for which measure the voltage on the positive side of the coil (see accompanying illustration). Check coil condition (see Checking the condition and replacing the ignition coil). Make the necessary corrections, then recheck.
5. Check the condition of the ignition coil. Using an ohmmeter, measure the resistive resistance of its primary and secondary windings (see Checking the condition and replacing the ignition coil). If breaks are found, replace the coil.
6. Check the functioning of the ignition control module (ICM).