There are two circuit into the car: low circuit and high-tension circuit. You can read about high-tension circuit below. High-tension circuit includes next components.
High-tension circuit components:
- The secondary winding of the coil;
- High voltage wires;
- Spark Plugs.
How to check (or to measure) a high low voltage circuit?
The high-tension (HT), we also describe it as secondary circuit carries high-voltage electricity. If there is no spark in the gap between the spark plug wire tip and the vehicle ground, the high voltage circuit is malfunctioning. I recommend testing this circuit in this sequence.
Check the secondary winding
To check the secondary winding, detach the central HT lead from the distributor cap (the distributor is excluded from the circuit), and set a gap of 5 – 7 mm between the tip of this lead and the vehicle ground. When switch on the ignition and a good high voltage current circuit to the distributor, a strong spark will appear in the gap.
Therefore, the fault we will looking in the high voltage wires which supplying the current to the sparkplugs, distributor cover and its rotor. Follow the wires of the high voltage, and then check the cover of the distributor and the rotor.
Check the distibutor
The distributor cover may have contamination of the central and side slots, breakage of coal or spring. If the slots are dirty, clean them with emery cloth. If you found the cracks on the distributor, it needs to replace.
When you checked the distributor cover and there are no any malfunctions, it is necessary to check the rotor condition and the insulation of the high voltage wires.
Don`t remove the rotor for this procedure. It is enough to bring the end of the central high voltage lead from coil to the side contact of the rotor at the distance of 3 mm. and open the breaker contacts by screwdriver. If a spark appears in the gap, the rotor is faulty and has a crack, so it must be replaced.
When the distributor excluded from the high voltage current circuit, there is no spark between the ground and the central high voltage wire of the ignition coil, check the high voltage wire, ignition coil or capacitor by faulty. If the ignition coil heats, it says about high voltage current may leak or a breakdown of the insulation of the secondary winding.
Check the spark plugs
Also, check the spark plugs by unscrewing them from the engine. If oil, fuel or carbon deposits are found on the spark plugs, they should be cleaned, dried. Start the engine again.