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How to check the capacitor for serviceability


How to check the capacitor for serviceability</a>

The engine ignition system is one of the main vehicle systems.

Thanks to her, we start the car and can move along the road.

In our country there are still a lot of vehicles with contact ignition. The capacitor is one of its elements.

Usually it does not fail, but drivers should always be ready for this.

Checking and replacing it on the road does not cause any difficulties.

You will need

  • - ohmmeter-
  • - crank handle (curved starter) -
  • - portable lamp



Take the device ohmmeter. Connect the capacitor to its housing, discharge it. Connect one ohmmeter probe to the wire end, the second to the housing (switch to the upper limit of the measurement). If the capacitor is in good condition, the needle will sharply deflect to the "0" side, and then smoothly return to the "?" Symbol. If you change the polarity, then the arrow will further deviate to "zero". Replace the defective capacitor.


Disconnect a coil of the ignition coil and a wireCapacitor from the clamp of the breaker. Take the portable lamp, it will enable to check the penetration of the capacitor on the car body. Connect it to the breaker clip. Turn the ignition on. Capacitor Is considered defective if the lampWill light up. It is used to reduce the burning of the contacts of the breaker and increase the secondary voltage. Connect the capacitor in parallel to them. When the contacts are opened, while the gap is at the minimum value, a spark jumps, and as a result, it also accumulates a charge. For each ignition system, there is a capacitor. Its capacity is usually located within the limits of 0.17-0.35 μF. For the contact system of cars of the VAZ family its value is 0.20-0.25 μF. In the case of a deviation in the capacity of the capacitor, the secondary voltage decreases. When charging or discharging the capacitor, it does not exceed 5 kV.


Disconnect the black wire from the ignition coil from the chopper clip, disconnect the capacitor wire from the breaker. Turn the ignition on. Make a touch between them. Capacitor Will be defective in case of a spark. The next way is to charge it with high-voltage current from the ignition coil, then discharge it to the car body. If there is a discharge spark between the mass and the capacitor wire with an audible click, then it is working. If there is no spark, then the capacitor is broken.


Disconnect the capacitor. Take the crank handle and start cranking the engine crankshaft. Remove the ignition distributor cover and switch on the ignition. A sign of a condenser failure is the excessive sparking of the breaker contacts at this time. If there is a too weak spark between the body and the central high-voltage wire, and if there is a strong enough sparking of the breaker contacts, the capacitor is defective and needs to be replaced.

How to check the capacitor for serviceability Was last modified: June 21st, 2017 By Zyzgyocs
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