TEST 2: Testing For Spark At The Ignition Coil Pack
IMPORTANT: This test section only applies if one or two spark plug wires that are connected to non-paired cylinders did not fire spark in TEST 1.
The lack of spark from the spark plug wire or wires you got in TEST 1 could be due to bad wires or a faulty ignition coil.
To figure out which one is causing the no-spark issue, you'll need to remove the spark plug wire that didn't fire from its ignition coil tower and attach a spark tester to the coil tower.
Once the spark tester is set up on the ignition coil tower, crank the engine to see if the tower produces a spark.
If the tower fires a spark, the spark plug wire is bad. If it doesn't, the ignition coil is faulty. It's that straightforward!
Let's get started:
- 1
Remove the spark plug wire that did not fire off spark from the ignition coil pack.
- 2
Place the spark tester directly on the ignition coil tower of the spark plug wire you just removed (see photo above).
- 3
Connect the spark tester to the battery negative (-) terminal with a battery jump start cable.
- 4
Have your helper crank the engine. The engine may start, so be careful.
- 5
You're gonna get one of two results: Spark or NO spark.
- 6
Remove the spark tester and reconnect the spark plug wire to the ignition coil tower.
- 7
Repeat steps 1 thru 6 on the other ignition coil tower of the other spark plug wire that didn't spark in TEST 1 (if applicable).
Let's take a look at what your test result means:
CASE 1: You got spark. This is the correct test result.
You can conclude that the spark plug wire is defective if you have:
- Confirmed that the spark tester did not spark when attached to the spark plug wire (TEST 1).
- In this test section, confirmed that the spark plug wire's tower does spark.
Replace all of the spark plugs with a new set.
CASE 2: You got NO spark. The ignition coil is bad. Replacing the ignition coil will solve the misfire condition and the misfire code lighting up the check engine light (CEL) on the instrument cluster.
TEST 3: Testing For Spark At The Ignition Coil Pack (Paired Cylinders)
IMPORTANT: This test section only applies if two spark plug wires that are connected to paired cylinders 1 & 5, or cylinders 2 & 6, or cylinders 3 & 4 did not fire spark in TEST 1.
In TEST 1, you identified two spark plug wires connected to paired cylinders that didn't spark. The next step is to check if the ignition coil towers connected to those wires are sparking.
To do this, we'll remove the spark plug wire that didn't spark from its ignition coil tower. Insert a spark tester into the coil tower as shown in the illustration above.
Then, we'll Ground the spark tester to the battery's negative (-) terminal using a battery jump-start cable. With everything set up, the last thing to do is to crank the engine to check if the spark tester sparks.
Since you need to test two ignition coil towers, start with one, check it for spark, and then test the second one.
These are the test steps:
- 1
Remove one of the spark plug wires that did not fire off spark from the ignition coil pack.
- 2
Place the spark tester directly in the ignition coil tower (see photo above).
- 3
Connect the spark tester to the battery negative (-) terminal with a battery jump start cable.
- 4
Have your helper crank the engine.
- 5
The spark tester should spark as the engine cranks.
- 6
Remove the spark tester and reconnect the spark plug wire to the ignition coil tower.
- 7
Repeat tests 1 thru' 5 on the other ignition coil tower whose spark plug wire did not fire off spark.
Let's take a look at what your test result means:
CASE 1: You got spark from only one tower. This result lets you know that the ignition coil is bad. Replace the ignition coil.
CASE 2 If you got spark from both towers. This result lets you know that the ignition coil is good and that the spark plug wires are bad. Replace all of the spark plug wires as a set.
CASE 3: You got NO spark from both towers. Generally, this test result tells you that the ignition coil bad.
To make sure that it's bad, I recommend that you confirm that the ignition coil is getting its activation signal.
If you got no spark from the towers that feed spark to cylinders 1 and 5 go to: TEST 5: Activation Signal For Cylinders 1 And 5.
If you got no spark from the towers that feed spark to cylinders 2 and 6 go to: TEST 6: Activation Signal For Cylinders 2 And 6.
If you got no spark from the towers that feed spark to cylinders 3 and 4 go to: TEST 7: Activation Signal For Cylinders 3 And 4.
TEST 4: Testing The Power (12 Volts) Circuit
The ignition coil has got to have 10 to 12 Volts to function. This voltage is delivered by the red with light green stripe (RED/LT GRN) wire of the coil pack's 4-wire connector.
In the the photo above of the front of the ignition coil pack connector, the RED/LT GRN wire is connects to the female terminal that I've labeled with the number 4.
To check if the RED/LT GRN wire is actually providing this voltage, we'll perform a simple voltage test using a multimeter.
By the way, these 10 to 12 Volts are only present in the RED/LT GRN wire when the ignition key is in the RUN or START position.
NOTE: Be careful not to damage the female terminal when probing it with your multimeter test lead. If the terminal is damaged, the entire connector will need to be replaced.
Let's get going:
- 1
Disconnect the ignition coil from its connector.
- 2
Put the multimeter in Volts DC mode.
- 3
Connect the black multimeter test lead to the battery negative (-) terminal.
- 4
Gently probe the front of the female terminal that connects to the RED/LT GRN wire with the red multimeter test lead (using an appropriate tool).
The terminal that connects to the RED/LT GRN is labeled with the number 4 in the photo above. - 5
Have your helper turn the key to the ON position (no need to crank the engine).
- 6
You should see 10-12 Volts on your multimeter.
Let's find out what your test result means:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct test result.
Since you've reached this test section because none of the spark plug wires sparked, the next step is to check that the PCM is providing an activation signal to each of the 3 individual coils that make up the ignition coil pack. Go to: TEST 8: Checking The IC Activation Signals.
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Re-check all of your connections and retest.
If still no voltage is present, this result exonerates the coil pack. Repairing the cause of this missing voltage will solve the 'no-spark no-start' condition of your Ford F150.