Testing the ignition system, on the 1992-1997 3.9L Dodge Dakota isn't hard. In this tutorial, I'm gonna' share with you all of the tests you need to perform to find out if the ignition system is causing a misfire problem or a no-start problem.
All of the tests are explained in detail. I'm also gonna' show you where you can buy the inexpensive tools you need to perform the tests.
Contents of this tutorial at a glance:
- Ignition System Test Basics.
- What Tools Do I Need To Test The Ignition System?
- TEST 1: Testing The Spark Plug Wires For Spark.
- TEST 2: Testing For Spark At The Distributor Cap.
- TEST 3: Testing The Ignition Coil's High Tension Wire For Spark.
- TEST 4: Testing The Ignition Coil For Spark.
- TEST 5: Making Sure The Ignition Coil Is Getting 12 Volts.
- TEST 6: Testing The Ignition Coil's Activation Signal.
- Other Causes Of A Misfire.
- Where To Buy The Ignition Coil And Save.
- Where To Buy The Distributor Cap, Distributor Rotor, Spark Plug Wires And Save.
- More 3.9L Dodge Dakota Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Sistema De Encendido (1992-1997 3.9L Dodge Dakota) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles since they use the exact same ignition system components: 1992, 1993, 1994, 1995, 1996 3.9L V6 Dodge Dakota.
WIRING DIAGRAM: The following wiring diagrams may come in handy:
- Ignition System Circuit Diagram (1992-1993 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1994-1995 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1996 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1997-1999 3.9L Dodge Dakota).
Ignition System Test Basics
The ignition system on the 1992-1997 3.9L Dodge Dakota is a conventional distributor-based ignition system. Its main components are:
- Ignition coil.
- Distributor.
- Crankshaft position sensor.
- Camshaft position sensor.
- Spark plug wires (high tension wires).
- Distributor cap and rotor.
When you turn the key to crank and start the engine, this is what happens:
- The crankshaft position (CKP) sensor starts to generate and feed a position signal to your Dodge Dakota's PCM (Powertrain Control Module=Fuel Injection Computer).
- The camshaft position (CMP) sensor starts to generate and feed a position signal to your Dodge Dakota's PCM.
- Once the fuel injection computer receives the crankshaft position and camshaft position sensor signals, it sends the ignition coil an activation signal.
- Once the ignition coil is activated by the PCM, it starts to spark.
- The ignition coil's spark is transmitted to the center of the distributor's cap by a high tension wire.
- The distributor rotor then distributes the spark to the distributor cap towers.
- From the distributor cap towers the spark is transmitted to the spark plugs via high tension wires.
With the help of this tutorial you'll be able to check the ignition coil's high tension wire, the spark plug wires, the distributor cap, and the ignition coil.
What Tools Do I Need To Test The Ignition System?
There are quite a few tools you'll need to test the ignition system on your 3.9L V6 Dodge Dakota. The cool thing is that none of them are expensive.
The most important tool you're gonna' need is a spark tester. Here are my recommendations:
- An HEI spark tester
- A spark tester is a must-have tool! It will help you get an accurate diagnostic test result as you test for spark. You can see an example of this tool here (and you can buy it here too): OTC 6589 Electronic Ignition Spark Tester.
- An LED light.
- You'll need the LED light for test step TEST 6. You can see an example of this LED light here: The LED Light Test Tool And How To Make One.
- Battery jump start cables.
- A multimeter.
- If you don't have a multimeter or would like to upgrade yours, see my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.
- A helper.
An ignition system wiring diagram always comes in handy and you can find them here:
- Ignition System Circuit Diagram (1992-1993 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1994-1995 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1996 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1997-1999 3.9L Dodge Dakota).
TEST 1: Testing The Spark Plug Wires For Spark
To get our ignition system diagnostic on the road, we're gonna' start off by testing all six spark plug wires for spark.
The purpose of this test is to find out if spark is missing from some or all six cylinders.
It's important to test for spark with a dedicated spark tester. Using a spark tester will ensure that your spark test results are accurate.
CAUTION: All of the ignition system tests are done while cranking the engine. Be careful and take all necessary safety precautions.
Let's get started:
- 1
Disconnect the #1 cylinder spark plug wire from its spark plug.
- 2
Attach the HEI spark tester to the spark plug wire (see the photo above).
- 3
Connect the HEI spark tester to the battery negative (-) terminal with a jump start cable.
- 4
Have your assistant crank the engine while you observe the spark tester.
NOTE: If you're testing a misfire condition, the engine will start so be careful. - 5
You're going to see only one of two results: the spark tester will spark or it won't spark.
- 6
Repeat the spark test on the remaining spark plug wires.
Let's examine your test results:
CASE 1: Spark is present at all six spark plug wires. This is the correct and expected test result.
You can correctly conclude that the crankshaft position sensor, the camshaft position sensor, the distributor rotor and cap, the ignition coil, and the spark plug wires are OK.
If you're trying to troubleshoot a misfire problem on your 1992-1997 3.9L Dodge Dakota, then take a look at the suggestions found here: Other Causes Of A Misfire.
CASE 2: All spark plug wires have NO spark. The next step is to check that the ignition coil's high tension wire is delivering spark to the distributor cap.
To check for spark from the ignition coil's high tension wire go to: TEST 3: Testing The Ignition Coil's High Tension Wire For Spark.
CASE 3: Some of the spark plug wires (but not all) have NO spark. This could be caused by bad spark plug wires or a bad distributor cap.
The next step is check for spark directly on the distributor cap towers that feed spark to the wires that did not fire off spark. For this test go to: TEST 2: Testing For Spark At The Distributor Cap.
