Wednesday, March 12, 2014

Columbia SC Auto Repair Pro on Bench Testing Your Ignition Coil



The best way to accurately test whether your ignition coil is really going bad is by using a multi-meter.  The Columbia, SC Auto Repair Pro directs you on how to test the ignition coil and offers more on why a multi-meter is the way to do it.

Why a Multi-Meter?

To understand, you have to learn a little bit about the ignition coil. Inside are two coils on top of one another. These are called windings.  There are both primary and secondary windings. Each of them has a specific function too.  Your primary winding builds up power to create the spark.  The secondary winding then sends that spark on to the distributor.  If either of the windings does not function correctly, it may cause the ignition coil to stop working correctly or at all.

If there is no spark at all, you know your ignition coil needs replacement.  In other cases though, it may be going bad but not actually dead yet.  In cases like this you may get a weak spark. Too weak a spark is inadequate, causing your auto to run very rough.  To take the speculation out of the ignition coil diagnosis, you should remove the coil. Using a multi-meter will provide actual data that will determine the coil’s condition.

How to Use a Multi-Meter to Test the Ignition Coil

First check your vehicle service manual for resistance specifications for your specific ignition coil.  You must have this information to proceed. If you cannot find your manual, an internet search on your make, model, year and the word manual will typically find it for you easily.

How to Test the Primary Winding

Your primary winding receives the battery voltage.  Using a multi-meter, you have to test the primary winding you find in the ignition coil.  If you have a traditional round coil, place the meter’s leads on the small outside poles.  With the newer type of enclosed ignition coil units, the leads need to be placed on the indicated poles.  Check your reading to establish whether it is within the specified range.  If so, you are fine. If the reading is even modestly out of spec, you want to go ahead and replace the coil.

How to Test the Secondary Winding

The secondary winding transfers the spark to the distributor. The distributor then sends it on to the spark plugs.  A secondary winding going bad can have no spark at all or it could be transferring only a weak spark.
Attach one of your multi-meter’s leads to the outer 12-volt pole.  The other will be at the center pole where the main wire is connecting to your distributor.  Use the meter to test your resistance. If it is within your owner manual’s specified range, great.   Even a minute irregularity points to needing the ignition coil replaced. 

If you would like for us test your ignition coil for you, contact our auto repair shop in Columbia, SC at 7917 Wilson Blvd. To get here, take Exit 71 off I-20.  Our ASE Certified Master Mechanic will take care of your every auto need. We offer top quality auto repairs on foreign and domestic autos as well as superior customer service.  Sanford’s Automotive Service has proudly served greater Columbia, SC and surrounding communities since 1989.  At Sanford’s Automotive Service, your auto repairs are always fixed right the first time!

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