TEST 4: Testing For The Triggering Signal
OK, you're here because you have confirmed that the ignition coil is not sparking, has 12 Volts and Ground. The next step is to verify that that ignition coil's is receiving the Triggering signal from the fuel injection computer.
Testing for the Triggering signal should be done with the ignition coil connected to its connector. The method I recommend to use is with them connected to their connectors and with a wire-piercing probe (to see what this tool looks like, click here: Wire-Piercing Probe.
With the Coil-On-Plug ignition coil that did not spark already removed and still connected to the HEI Spark Tester and to its connector:
- Put the multimeter in Hertz (Hz) mode.
- Probe the circuit labeled with the number 2 (see the photo above) with the black multimeter test lead (using an appropriate tool to pierce the wire).
- With the red multimeter test lead probe the BATT (+) Positive terminal.
- You should see fluctuating values of 30 to 60 Hertz as the engine starts and runs on your multimeter.
Let's interpret your multimeter test result:
CASE 1: The multimeter registered 30 to 60 Hertz (Hz) as the engine cranked and started. This test result confirms the Triggering signal is present. This result indicates that the Coil-On-Plug Ignition Coil on your Suzuki is bad and needs to be replaced.
CASE 2: The multimeter DID NOT register 30 to 60 Hertz (Hz) as the engine cranked and started. Re-check all of your connections and repeat the test.
If still no Hertz readings, then this results eliminates the ignition coil as the source of the no-spark condition/misfire, since without the Triggering signal the ignition coil will not work.
TEST 5: Checking For Carbon Tracks
If all of the spark plug boots fired off spark in TEST 1 and yet the vehicle is experiencing a misfire condition, then the most likely causes are: 1) the spark plug boots spark plugs have developed carbon tracks or 2) the spark plugs and spark plug boots are swimming in engine oil or 3) both of the aforementioned conditions. All of these conditions are a very common occurrence in this type of Coil-On-Plug ignition system.
If the spark plug boots spark plugs are swimming in engine oil, it's usually due to the valve cover gasket leaking oil into the spark plug tubes. This oil will cause the ignition system to misfire and/or cause carbon tracks to form as the spark cooks the oil.
In the photo above, you'll see what a carbon track looks like on the spark plug boot and on the spark plugs. The next step is to remove the spark plugs and spark plug boots to visually inspect them for carbon tracks and/or to see if the are all oil-soaked.
If the spark plugs are oil-soaked and/or with carbon tracks, you'll need to replace them all along with the spark plug boots. Failure to replace one without the other will only make the carbon track return and/or continue to misfire still.
What If No Carbon Tracks Or Cracks Exist?
Now, if no carbon tracks are visible on any of the spark plugs, or spark plug boots, then the ignition system is not the cause of your misfire condition. I would check engine compression and the fuel injectors among several things.
If this info really saved the day, buy me a beer!