TEST 2: Check The Ignition Coil For Spark
Testing any of the four ignition coils on your 1.7L Honda Civic involves a spark test with a spark tester.
Why a spark tester? Because this is the most accurate way of diagnosing any one of the four ignition coils.
You can use any type of spark tester you want or have, although the one that I use, trust, and recommend is the HEI spark tester.
IMPORTANT: You'll need to test for spark with the engine cranking. Be careful, stay alert, and use common sense.
OK, these are the steps:
- 1
Remove the ignition coil from its place on the valve cover.
NOTE: You'll need to disconnect the ignition coil from its harness connector. Once the ignition coil is off, reconnect it back to its harness connector. - 2
Connect an HEI spark tester to the ignition coil.
NOTE: You can use any type of spark tester. The only reason I use and recommend the HEI spark tester is because this spark tester is accurate (and you don't have to worry about interpreting the color of the spark). - 3
Ground the HEI spark tester with a battery jump start cable directly on the battery negative (-) terminal.
- 4
Have a helper crank the engine while you observe the spark tester.
- 5
The spark tester will do one of two things: spark or NOT spark.
Repeat this test once more to make sure of your test result.
Let's see what your test results mean:
CASE 1: All ignition coils sparked. This is the correct and expected test result and it tells you that the ignition coils are OK.
If a misfire code still accuses this cylinder as misfiring, it's important that you now check the following:
- Check to see if the valve cover gasket is leaking engine oil onto the spark plug and COP coil boot. If these are oil soaked, you've found the source of the misfire (you'll need to replace the valve cover gasket, the coil boot and the spark plug).
- Check to see if the spark plugs have carbon tracks on their porcelain insulator. To learn more about carbon tracks, the following tutorial will help:
- Carbon Tracks Are A Common Cause Of Ignition Misfires (at: easyautodiagnostics.com).
- Do an engine compression test to see if that cylinder has low engine compression. The following tutorial will help you test engine compression:
CASE 2: An ignition coil DID NOT spark. This spark test result usually indicates that the COP ignition coil is bad, but not always. I suggest one more test to make sure.
The next step is to swap the ignition coil (that didn't spark) with the one next to it and then check for spark again.
For this test and a better explanation of it, go to: TEST 3: Swap The 'No Spark' COP Coil.
TEST 3: Swap The 'No Spark' COP Coil
In this last test step, you're gonna' swap the ignition coil that wasn't sparking with the one next to it (or one of the other three that you know is sparking).
Why swap ignition coils? This is to double check that the electrical connector of the one that isn't sparking is supplying power, Ground, and an activation signal.
Alright, this is what you'll need to do:
- 1
Disconnect and remove the COP ignition coil that did not spark in the previous test section.
- 2
Choose one of the other COP coils that is sparking and remove it from its place.
NOTE: If you need to make sure that this COP ignition coil is sparking, you can test it with your spark tester. - 3
Once the good COP coil is removed, connect it to the bad COP coil's electrical connector.
- 4
Connect the HEI spark tester to the good COP coil.
- 5
Ground the HEI spark tester with a jump start cable directly on the battery negative (-) terminal.
- 6
Place the bad COP ignition coil in the location of the good one you just removed and bolt it down.
- 7
Have your helper crank the engine once everything is set up.
- 8
You'll see one of two results:
1.) The spark tester will spark.
2.) The spark tester WILL NOT spark.
Let's take a look at your test results:
CASE 1: The COP ignition coil sparked. This tells you that the COP coil that did not spark in TEST 2 is bad and needs to be replaced.
Here's why: By placing a good and sparking ignition coil in place of the bad one and having spark still come out of the good one, proves that the non-sparking coil:
- Is getting power (10 to 12 Volts).
- Is getting the PCM's triggering signal.
- Is being fed with Ground.
CASE 2: The COP ignition coil DID NOT spark. This lets you know that the COP ignition coil that did not spark is not sparking because one of the three wires of its harness connector is missing a signal.
The next step for you is to:
- Check that the ignition coil is being fed with power (10 to 12 Volts).
- That the PCM's is providing triggering signal.
- That the ignition coil is being fed Ground.
Although these specific tests are beyond the scope of this article, you now have eliminated the ignition coil as bad and now have an idea of what direction your diagnostic/troubleshooting needs to go in.
