How To Test The Ignition System (1993-1995 2.5L Caravan And Voyager)

In this tutorial I'm gonna' explain how to test the igntion system to find out if it's causing a misfire or a no-start problem.

You're gonna' be surprised just how easy it is to diagnose the spark plug wires, the distributor cap and rotor, and the ignition coil.

All of the tests are explained in detail and in plain English. And you don't need any epensive tools to perform the tests!

You can find this tutorial in Spanish here: Cómo Probar El Sistema De Encendido (1993-1995 2.5L Caravan y Voyager) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles since they use the exact same ignition system components:

• 2.5L Dodge Caravan: 1993, 1994, 1995.
• 2.5L Plymouth Voyager: 1993, 1994, 1995.

WIRING DIAGRAM: The following wiring diagrams may come in handy:

• Ignition System Wiring Diagram (1993 2.5L Caravan And Voyager).
• Ignition System Wiring Diagram (1994-1995 2.5L Caravan And Voyager).

Ignition System Test Basics

The ignition system on the 1993, 1994, 1995 2.5L Dodge Caravan (Plymouth Voyager) is a conventional distributor-based ignition system. Its main components are:

• Ignition Coil.
• Distributor.
• Distributor pickup coil (crankshaft 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:

1. The distributor pickup coil starts to generate and feed a position signal to the fuel injection computer.
2. Once the fuel injection computer receives the distributor pickup coil's signal, it sends the ignition coil an activation signal.
3. Once the ignition coil is activated by the fuel injection computer, it starts to spark.
4. The ignition coil's spark is transmitted to the center of the distributor's cap by a high tension wire.
5. The distributor rotor then distributes the spark 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 rotor, 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 2.5L Dodge Caravan (Plymouth Voyager). 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:

1. An HEI spark tester
   1. 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.
2. 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 (at: easyautodiagnostics.com).
3. Battery jump start cables.
4. 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 (at: easyautodiagnostics.com).
5. A helper.

An ignition system wiring diagram always comes in handy and you can find them here:

• Ignition System Wiring Diagram (1993 2.5L Caravan And Voyager).
• Ignition System Wiring Diagram (1994-1995 2.5L Caravan And Voyager).

TEST 1: Testing The Spark Plug Wires For Spark

To get the most accurate test result from the ignition system test, it's important that you do 2 things:

• Test all 4 spark plug wires for spark.
• Use a dedicated spark tester to test for spark.

If you don't have a spark tester, buy one at your local auto parts store or buy it online.

I personally recommend the HEI spark tester because of how accurate it is (and it doesn't cost an arm and a leg), but you can use any spark tester. You can learn more about the HEI spark tester here: HEI Spark Tester. (at: easyautodiagnostics.com)

CAUTION: All of the ignition system tests are done while cranking the engine. Be careful and take all necessary safety precautions.

These are the test steps:

1. 1

   Disconnect the #1 cylinder spark plug wire from its spark plug.

2. 2

   Attach the HEI spark tester to the spark plug wire (see the photo above).

3. 3

   Connect the HEI spark tester to the battery negative (-) terminal with a jump start cable.

4. 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. 5

   You're going to see only one of two results: the spark tester will spark or it won't spark.

6. 6

   Repeat the spark test on the remaining spark plug wires.

Let's examine your test results:

CASE 1: Spark is present at all four spark plug wires. This is the correct and expected test result.

You can correctly conclude that the distributor pickup coil, the distributor rotor and cap, the ignition coil, and the spark plug wires are OK.

If your 2.5L Dodge Caravan (Plymouth Voyager) does not start, you can conclude that the ignition system is not behind the problem.

If you're trying to troubleshoot a misfire problem on your 1993, 1994, 1995 2.5L Dodge Caravan (Plymouth Voyager), then take a look at the suggestions found here: Other Causes Of A Misfire.

CASE 2: All spark plug wires have NO spark. The engine will not start if spark is missing from all four spark plug wires.

The next step is to check that the ignition coil's high tension wire is delivering spark to the distributor cap. For this test go to: TEST 2: 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 test result tells you that those spark plug wires that did not spark are bad and need to be replaced.