How to Test the Ignition Coil
-No Start Tests (Chrysler 3.9L, 5.2L, 5.9L)

IGNITION COIL TEST 1: Checking the High Tension Wire

There's a good chance that you have already tested for spark (and you got no spark) or maybe you haven't done any tests at all... either way, I recommend that you start here.

My test instructions call for using an HEI spark tester and you may be asking yourself if this is an absolute must.. and the answer is NO.

You can use any type of spark tester you want. The biggest reason I recommend the HEI spark tester is that it is a very, very accurate spark tester (and one of the most inexpensive). In the section Why the HEI Spark Tester, I go more in depth about this.

The focus of this very first ignition coil test, is to see if the ignition coil high tension wire (the one that feeds the coil's spark to the distributor cap) is good or BAD.

OK, this what you need to do:

  1. 1

    Disconnect the ignition coil's high tension wire from the distributor cap but leave the end that connects to the ignition coil connected (to the ignition coil).

  2. 2

    Now, on the end that connects to the center of the distributor cap, attach the HEI spark tester (see photo in image viewer).

  3. 3

    Using a battery jump start cable, ground the HEI spark tester to the battery negative (-) terminal.

  4. 4

    When everything is set, have a helper crank up the engine while you observe the spark tester from a safe distance.

  5. 5

    The HEI spark tester will give you one of two results: spark or no spark.

OK, let's take a look at what your test results mean:

CASE 1: You got spark: This test result automatically tells you that the ignition coil and the wire are good. If there's spark, the ignition coil is not the cause of your Dodge's no start no spark condition.

Since quite a few things can cause a cranks but does not start condition, I recommend taking a look at the following tutorial:

  1. How to Test a No Start Condition (Dodge 3.9L, 5.2L, 5.9L).

CASE 2: You got no spark: this test result doesn't condemn the ignition coil or the high tension wire just yet.

Then next step, in your ignition coil diagnostic, is to check for spark directly on the ignition coil's tower with the spark tester. So, to further pinpoint the problem, go to IGNITION COIL TEST 2.

IGNITION COIL TEST 2:
Testing for Spark Directly on the Coil Tower

So far, in troubleshooting your Dodge's no spark- no start condition... you have confirmed that the ignition coil's high tension wire is not delivering spark to the distributor cap.

In this test step, you're gonna' test for spark directly on the ignition coil to find out if the spark plug wire (high tension wire) that connects the ignition coil to the distributor cap is BAD or not.

Depending on your spark test result, you'll know if the high tension cable is BAD and not letting spark thru' to the distributor cap (this happens quite a bit) or will let you know that you need to continue to the next test.

Alright, this is what you'll need to do:

  1. 1

    OK, disconnect the high tension wire from the ignition coil.

  2. 2

    Now, connect the HEI spark tester to the ignition coil's tower using a small piece of vacuum hose. This is important, see how I've done it in the photo in the image viewer.

  3. 3

    Now ground the spark tester using a battery jump start cable directly on the battery negative (-) terminal.

  4. 4

    When ready have your helper crank the engine as you eyeball the HEI spark tester, you'll see one of two results: spark or no spark.

OK, let's take a look at what your test results mean:

CASE 1: You got spark: this spark test result tells you that the high tension wire is FRIED and is the cause of your no start condition. Replace all of the spark plug wires as a set.

If you'd like to save a few bucks on the spark plug wire set, take a look at the section: Where to Buy the Ignition Coil and Save.

CASE 2: You got no spark: this spark test result eliminates the high tension wire and means you're getting closer to the actual cause of the ignition coil's no spark condition.

The next steps are to verify that the Powertrain Control Module (fuel injection computer) is feeding power and activating the ignition coil. For this test, go to IGNITION COIL TEST 3.

Dodge Vehicles:

  • B1500, B2500, B3500 3.9L, 5.2L, 5.9L
    • 1995, 1996, 1997, 1998
  • Dakota 3.9L, 5.2L, 5.9L
    • 1997, 1998, 1999
  • Durango 3.2L, 5.2L, 5.9L
    • 1997, 1998, 1999, 2000, 2001, 2002, 2003

Dodge Vehicles:

  • Ram 1500, 2500, 3500 3.9L, 5.2L, 5.9L
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
  • Ram Van 1500, 2500, 3500 3.9L, 5.2L, 5.9L
    • 1997, 1998, 1999, 2000, 2001, 2002, 2003

Jeep Vehicles:

  • Grand Cherokee 5.2L, 5.9L
    • 1997, 1998