TEST 2: Primary Ignition Coil Tower Spark Test
IMPORTANT: This test applies only if one of the four spark plug wires of the primary ignition coil did not spark in TEST 1.
What we're going to do in this test section is to check for spark directly on the ignition coil tower of the high tension wire that did not spark in TEST 1.
If the spark tester sparks, then you can conclude that the spark plug wire is defective. If the spark tester does NOT spark, you can conclude that the ignition coil pack is defective.
NOTE: The spark tester must be held in place in the ignition coil pack tower. You can easily and safely do this by Grounding the spark tester with a battery jump start cable. The battery jump start cable will make it easy (and safe) to hold the spark tester in the coil tower.
These are the test steps:
- 1
Disconnect the spark plug wire that did not spark in TEST 1 from its ignition coil tower.
- 2
Place the spark tester in the ignition coil tower. This is the coil tower that you just removed its high tension wire.
- 3
Ground the spark tester directly to the battery negative (-) terminal using a battery jump start cable.
- 4
Have your helper crank and start the engine while you observe the spark tester.
- 5
The spark tester should spark with the engine running.
Let's analyze your spark test result:
CASE 1: The spark tester sparked. This is the correct test result and lets you know that the primary ignition coil pack is good.
This test result also tells you that the spark plug wire (high tension wire) that connects to this coil tower is defective. Replace all of the 8 spark plug wires with a new set.
Spark plug wires will eventually stop transmitting spark from the ignition coil to the spark plug. This is a very common problem.
CASE 2: The spark tester DID NOT spark. This test result lets you know that the primary ignition coil pack is defective and needs to be replaced.
TEST 3: Checking For Spark (Intake Side)
The secondary ignition coil is the one that supplies spark to the intake manifold spark plugs.
To start off our secondary ignition coil pack diagnostic, we're gonna' check for spark at all 4 intake manifold side spark plug wires.
NOTE: Even if you have a misfire trouble code pinpointing a specific cylinder, it's important that you test all four spark plug wires.
IMPORTANT: To get the most accurate test result, you should use a dedicated spark tester. The spark tester that I recommend that you use is the: OTC 6589 Electronic Ignition Spark Tester.
Let's get started:
- 1
Disconnect the spark plug wire from the #1 cylinder spark plug.
- 2
Connect the spark tester to the spark plug wire.
Ground the spark tester with a jump start cable to the battery negative (-) terminal of your Ford Ranger. - 3
Have your helper start the engine while you observe the spark tester.
- 4
The spark tester should spark the entire time the engine is running.
- 5
Repeat the spark test on the remaining intake manifold side spark plug wires.
Let's examine your spark test results:
CASE 1: All of the intake manifold side spark plug wires sparked. This is the correct test result and lets you know that the secondary ignition coil is working correctly.
You can also conclude that the 4 spark plug wires, you just tested, are functioning correctly.
CASE 2: One of the intake manifold side spark plug wires DID NOT spark. The next step is to check for spark directly on the ignition coil tower that connect to this non-sparking spark plug wire.
For this test go to: TEST 5: Secondary Ignition Coil Tower Spark Test.
CASE 3: Two intake manifold side spark plug wires that connect to two 'paired' cylinders DID NOT spark (paired cylinders are: #1 & #4 and #2 & #3). This usually indicates that the intake side ignition coil pack is defective.
But to be sure, the next step is to check for spark directly on the ignition coil towers that connect to these two non-sparking spark plug wires. Go to: TEST 6: Secondary Ignition Coil Tower Spark Tests (Paired Cylinders).
