TEST 4: Testing for the Triggering Signal

Making Sure The Fuel Injection Computer Is Activating The Ignition Coil. How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

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.

There are two ways of doing this test, with a multimeter that can read Hertz frequency or just by swapping coils. If you just want to test them by swapping COP coils, go to the next heading below.

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:

  1. Put the multimeter in Hertz (Hz) mode.
  2. Probe the circuit labeled with the number 3 (see photo in image viewer) with the black multimeter test lead (using an appropriate tool to pierce the wire).
  3. With the red multimeter test lead probe the battery positive (+) terminal.
  4. You should see fluctuating values of 30 to 60 Hertz as the engine starts and runs on your multimeter.

CASE 1: If the multimeter registered 30 to 60 Hertz (Hz) as the engine cranked and started, then the Triggering Signal is present. This result indicates that the Coil-on-Plug ignition coil on your Honda is BAD and needs to be replaced.

CASE 2: If the multimeter DID NOT register 30 to 60 Hertz (Hz) as the engine cranked and started, re-check all of you connections and repeat the test again. 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.

Testing The Triggering Signal Without A Multimeter

Making sure that the Triggering Signal is present can be done without a multimeter and in this test step I'll show you how:

  1. Remove the COP coil that did not spark and set it aside.
  2. Remove one of the adjacent COP ignition coils that does spark.
  3. Now connect the COP ignition coil (that sparks) to your HEI spark tester and then connect it to the electrical connector of the COP coil that does not spark.
  4. When all is ready, have your trusty assistant crank the engine and notice if the HEI spark tester sparks. Be careful, the engine may start.
  5. If the COP coil sparks, then you now know that the Triggering Signal is present in this connector.

Here are the test result interpretations:

CASE 1: If you got spark, then the Triggering Signal is present. This result indicates, beyond a shadow of a doubt, that the Coil-on-Plug ignition coil on your Honda is BAD and needs to be replaced. Replacing the ignition coil will solve the misfire condition.

CASE 1: If you got NO spark, re-check all of you connections and repeat the test again. If still no spark, then this results eliminates the ignition coil as the source of the NO SPARK condition/misfire, since without the Triggering Signal the COP ignition coil will not work.