The diagnostic methods of engine fail to start in electronic ignition system are similar with the conventional ignition system. If you have mastered the skills to diagnose the problem in conventional ignition system, it will be easy to diagnose your car with electronic ignition system.
(1) Visual inspection
First, Check for loose the coil to distributor high tension wire and low-voltage circuit between the ignition coil and distributor. If so, restart the engine and see if it can be started after troubleshooting. If the visual examination does not find any problem, proceed to the next troubleshooting step.
(2) Spark jump testing of the coil to distributor high tension wire
Pull out the coil to distributor high tension wire, and make coil to distributor high tension wire terminal 5-8mm away from the engine block, then turn on the ignition switch, when start the engine with the starter, see whether to spark jump between distributor high tension wire terminal and the engine block. There are three cases：The spark is strong; the spark is weak or the spark jumps.
A. If the spark is very strong, it indicates that the low-voltage circuit and ignition coil is basically normal. While the fault is in the high-voltage circuit or spark plug, proceed to carry out the next step fault diagnosis.
B. If the spark is very weak, it may be caused by faulty components, such as electronic ignitor, ignition coil or other component or poor connection of spark plug wire. Further diagnosis can be made in step (4).
C. If there is no spark, the possible causes of the fault include Ignition signal generator，electronic ignitor, ignition coil, or poor contact of the ignition switch and ignition coil low-voltage circuit. Step 5 can be used for further troubleshooting.
Insert back into the high tension lead, pull out the spark plug wire on a cylinder spark plug for test. If the spark does not jump or the spark is very weak, it indicates electric leakage or open circuit in distributor cap, rotor or spark plug wire, these parts need to be repaired. If the spark is still strong, the spark plug shall be removed for inspection. If the spark plugs of all cylinders are in good condition, then check the oil circuit, ignition timing and other possible faults that may cause the engine to fail to start.
(4) Diagnose the cause of weak spark with instantaneous short circuit method
When turn on the ignition switch, and conduct jump spark test of coil to distributor high tension wire by instantaneous ground between the "-" terminal of ignition coil, to see whether the spark at the terminal of the spark plug wire becomes stronger. If the spark becomes stronger, it is necessary to replace new electronic ignitor; If the spark is still weak, check or replace the ignition coil.
(5) Diagnose the causes of no spark jump with instantaneous short circuit method
Connecting the ignition switch, use a lead to ground with the terminal"-" of ignition and conduct jump spark test of the high tension lead by instantaneous ground. If there is jump spark, it is necessary to troubleshoot the signal generator. If the spark is still not jumping, then see whether there is a spark when grounding at the moment. If not, check whether the low-voltage loop circuit of the ignition system is open circuit or the primary winding of the ignition coil is open circuit; If there is a spark when contacting. check whether the secondary winding of the ignition coil is open or short circuit fault, and whether coil to distributor high tension wire is open circuit.