An ignition coil is a type of induction coil, a high voltage autotransformer that uses a burst of self-induction in the primary winding. Its malfunction may consist in the breakage of any of the windings, as well as in the presence of short-circuited turns and breakdowns.
Instructions
Step 1
After de-energizing the on-board network, disconnect and remove the ignition coil. Sketch how it was connected. Inspect it visually. There should be no chips on its plastic parts - they can cause breakdowns. If the bobbin case is dirty, clean it - dirt can cause high voltage leaks.
Step 2
Check coil for breaks. To do this, use a conventional ohmmeter. Ring first the primary, then the secondary. The first should have very little resistance, the second - much more, but the main thing is that neither one nor the other should have it close to infinity. If at least one of the windings is cut off, the bobbin is faulty. Note that the common lead is the coil body. Do not touch the leads and metal parts of the probes during continuity, so as not to get an unpleasant shock by the self-induction voltage.
Step 3
After making sure that there are no breaks in both windings, check the coil for short-circuited turns. Take another bobbin of the same type, which is known to be good. Connect an AC voltmeter to the secondary winding. Apply a sinusoidal signal with a frequency of several tens of hertz and an amplitude of about 2 V to the primary winding. Record the voltmeter readings, turn off the signal, and then repeat the experiment with the reference coil. If the readings differ significantly, there are short-circuited loops. Such a reel can generate a very low voltage that is not able to break through the spark gap of the candle. Do not touch the coil leads while checking.
Step 4
Test the reel for breakdowns. Connect its primary winding to a powerful 12-volt DC source through a button with contacts rated for a current of at least 20 A. Parallel to the button, a paper capacitor of the same capacity as installed in the ignition system and designed for a voltage of at least 1 must be connected kV. Connect a spark plug to the secondary winding. Turn on the source and quickly press and release the button several times. If the crackle is heard in the coil itself with almost the same volume as in the candle, there are breakdowns and the coil is faulty. Do not bring your ear too close to prevent the spark from entering it.
Step 5
Based on the results of the check, decide whether to install the spool back or replace it with a new one. The latter must have the same parameters. If the coil is good and the ignition is not working, then other system components are faulty.
