Testing The Ignition System (1998-2003 3.9L Dodge Dakota)

TEST 6: Testing The Ignition Coil's Activation Signal

So far you have confirmed that:

• None of the spark plug wires are sparking (TEST 1).
• The ignition coil's high tension wire is not sparking (TEST 3).
• The ignition coil is not sparking (TEST 4).
• The ignition coil is receiving 10 to 12 Volts on the DK GRN/ORG wire of its connector (TEST 5).

Now, we're gonna' make sure that the ignition coil is getting an activation signal on the black with grey stripe (BLK/GRY) wire of its 2-wire connector.

To test the presence of this signal, we're gonna' use an LED light. You can see an example of this tool here: The LED Light Test Tool And How To Make One.

NOTE: LEDs are polarity specific and so their wires will be black and red. This also means that the red and black leads must be connected in a very specific way to get a correct test result.

Let's get started:

1. 1

   Disconnect the ignition coil from its electrical connector.

2. 2

   Connect red LED wire to the dark green with orange stripe (DK GRN/ORG) wire of the ignition coil's wiring harness connector.
   
   This is the wire that feeds 12 Volts to the ignition coil and it's labeled with the number 2 in the photo above.

3. 3

   Connect black LED wire to the black with grey stripe (BLK/GRY) wire of the ignition coil's wiring harness connector.
   
   This is the wire that feeds the activation signal to the ignition coil and it's labeled with the number 1 in the photo above.

4. 4

   Have an assistant crank the engine.

5. 5

   The LED light should blink ON and OFF the whole time the engine is being cranked.
   
   NOTE: Don't worry about what the LED light does before or after your helper starts cranking the engine. The only results you're interested in interpreting are the results obtained with the engine cranking.

Let's examine your test result:

CASE 1: The LED flashed ON and OFF. This is the correct test result.

With this test result you can conclude that the ignition coil, on your 3.9L Dodge Dakota, is bad only if you have:

• Confirmed that all of the spark plug wires are not sparking (TEST 1).
• Confirmed that ignition coil's high tension wire does not spark (TEST 3).
• Confirmed that the ignition coil's tower does not spark (TEST 4).
• Confirmed that the ignition coil is getting 10 to 12 Volts (TEST 5).
• Confirmed that the ignition coil is getting an activation signal (TEST 6).

Here's why: If the ignition coil is getting 10 to 12 Volts (TEST 5) and it's getting an activation signal (TEST 6) then it has to spark. Since your test result confirms that it does not spark, you can conclude that the ignition coil is defective.

Replace the ignition coil to solve the no-start problem on your 3.9L V6 Dodge Dakota.

CASE 2: The LED DID NOT flash ON and OFF. Without the activation signal the ignition coil will not spark.

Re-check all of your connections and repeat the test. If the LED light does not flash ON and OFF then the most likely cause of this missing signal is a bad crankshaft position sensor or a bad camshaft position sensor.

Testing the crankshaft and camshaft position sensors can easily be done with a multimeter. The following tutorials will help you with these tests:

• How To Test The Crankshaft Position Sensor (1998-2003 3.9L Dodge Dakota).
• How To Test The Camshaft Position Sensor (1998-2003 3.9L Dodge Dakota).

Other Causes Of A Misfire

So you've done all of the spark tests and found no problems but your 3.9L V6 Dodge Dakota still runs rough. Well, here are a couple of suggestions that might help:

1. Check for broken spark plugs.
   • This usually happens at tune-up time (if you have dropped one on the floor).
   • You power washed the engine (this is something that should never be done on any Dodge Dakota vehicle).
2. Check for carbon tracks on the spark plugs.
   • Check to see if carbon tracks have formed on the spark plug's porcelain insulator. The photo above shows what a carbon track looks like on the inside of the spark plug wire boot and on the ceramic insulator of the spark plug.
3. Check engine compression test.
   • One of the most overlooked diagnostic tests to find the root cause of misfire is the compression test.
   • You can find the engine compression test explained here: How To Test Engine Compression (1993-1999 3.9L Dodge Dakota).
4. Check the resistance of the fuel injectors.
   • This simply involves testing the internal resistance of the fuel injectors to make sure that none are shorted internally.

Where To Buy The Ignition Coil And Save

The 2000-2003 3.9L V6 Dodge Dakota's ignition coil is not an expensive ignition system component. The following links will help you to comparison shop and hopefully save you a few bucks on its purchase:

NOTE: The ignition coil fits the following vehicles: 1998, 1999, 2000, 2001, 2002, 2003 3.9L V6 Dodge Dakota.

Where To Buy The Distributor Cap, Distributor Rotor, Spark Plug Wires And Save

The following links will help you to comparison shop and hopefully save you a few bucks on its purchase:

NOTE: The distributor cap, the distributor rotor, and the spark plug wires fit the following vehicles: 1998, 1999, 2000, 2001, 2002, 2003 3.9L V6 Dodge Dakota.

More 3.9L Dodge Dakota Tutorials

You can find a complete list of 3.9L Chrysler and Dodge tutorials in this index:

• Chrysler 3.9L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The Starter Motor (1991-1995 3.9L Dodge Dakota).
• How To Test Engine Compression (1993-2003 3.9L Dodge Dakota).
• How To Test For A Blown Head Gasket (1993-2003 3.9L Dodge Dakota).
• Engine Management Sensor Circuit Diagram (1994-1995 3.9L V6 Dodge Dakota).