When the ignition coil fails, on your 1993-1995 2.5L SOHC Dodge Dakota, the engine is going to crank but not start due to a lack of spark.
Testing the ignition coil, to see if it's defective or not, is a pretty easy thing to do and in this tutorial I'll explain the test in a step by step way.
Contents of this tutorial at a quick glance:
- Ignition Coil Circuit Descriptions.
- Making Sure Spark Is Missing At All Spark Plug Wires.
- TEST 1: Testing For Spark Directly On The Ignition Coil Tower.
- TEST 2: Making Sure The Ignition Coil Is Getting Power.
- TEST 3: Checking For The Ignition Coil Control Signal.
- Where To Buy The Ignition Coil.
You can find the typical ignition system circuit diagram here: 1993-1995 2.5L Dodge Dakota Ignition System Wiring Diagram.
Puedes encontrar este tutorial en Español aquí: Cómo Probar La Bobina De Encendido (1993-1995 2.5L Dodge Dakota) (en: autotecnico-online.com).
Ignition Coil Circuit Descriptions
The ignition coil is a very simple device. It only has 2 wires coming out of its connector.
One wire feeds it with battery power and the other one supplies the activation signal from your Dakota's fuel injection computer. This activation signal is the one that induces the ignition coil to start sparking away.
Since we need to know what each wire does, here is a brief description of each one:
|Ignition Coil Connector|
|1||DK GRN/ORG||Power -Battery power|
|2||GRY||IGC -Ignition coil control signal|
Making Sure Spark Is Missing At All Spark Plug Wires
To successfully diagnose the ignition coil on your 2.5L Dodge Dakota, the very first thing you need to do is to make sure that there isn't any spark coming out of the spark plug wires.
So if you haven't already, you need to test every spark plug wire for spark. If no spark is coming out of any of them, then proceed with the ignition coil test in this tutorial.
Now if even one spark plug wire has spark, then you can conclude that the ignition coil is OK and not defective.
One more thing: I recommend using a dedicated spark tester for all of your tests. This will ensure an accurate test result. I recommend using an HEI spark tester. This bad boy is not expensive and very, very accurate! You can find out where to buy it here: The HEI Spark Tester.
TEST 1: Testing For Spark Directly On The Ignition Coil Tower
After having confirmed that none of the four spark plug wires are sparking, the next step is to check for spark directly on the ignition coil's tower.
This spark test will help us to indirectly test the high tension wire (spark plug wire) that connects the ignition coil to the distributor cap and the distributor cap/rotor.
To get the most accurate test results from this test, you need to use a dedicated spark tester. As I mentioned before, the one that I recommend you use is an HEI spark tester (ince it's the most accurate spark tester out there).
These are the test steps:
Disconnect the high tension wire that connects to the middle tower of the distributor cap.
NOTE: This is the high tension wire that connects the ignition coil to the distributor cap.
Place the HEI spark tester directly on the ignition coil tower. Use a small piece of vacuum hose to attach the spark tester to the metal tip of the ignition coil's tower (see illustration above).
Ground the spark tester, using a battery jump start cable, to the battery negative (-) post.
Have your helper crank the engine as you secure the spark tester on top of the ignition coil tower
The spark tester should spark as the engine turns if the ignition coil is functioning.
Let's take a look at what your test results mean:
CASE 1: The ignition coil sparked away. This is the correct and expected test result and tells you that your 2.5L Dodge Dakota's ignition coil is not defective.
This test result also tells us that the ignition coil's high tension wire and/or the distributor cap rotor are not transmitting the ignition coil's spark to the spark plugs. These components need to be replaced.
CASE 2: The ignition coil did not spark away. The next step is to make sure the ignition coil is getting power. For this test, go to: TEST 2: Making Sure The Ignition Coil Is Getting Power.