TEST 1: Testing For Spark At The Spark Plug Wire
You might already have an idea which cylinder is the one misfiring or maybe not. Either way, I suggest that you test all four cylinders for spark. Remember, the successful outcome of your trouble-shooting/diagnostic lies in the usage of a spark tester.
The following test steps assume that you're gonna' test all cylinders for spark by starting with #1 cylinder:
- 1
Remove the spark plug wire (high tension cable) from the spark plug and attach the spark tester to it.
- 2
Ground the spark tester with a battery jump start cable as shown in the photo above.
- 3
When a safe distance from the engine, have your helper crank the vehicle.
NOTE: The vehicle may or may not start, either way be careful. - 4
Observe the spark tester to see if spark jumps across its air gap as the vehicle cranks or starts.
- 5
You're gonna' get one of two results: spark or no spark.
- 6
Now repeat this test on the other cylinders.
IMPORTANT: To interpret the results of your spark test, you must remember that the ignition coil feeds spark to two engine cylinders simultaneously from one ignition coil within the coil pack and the other two cylinders with the other ignition coil (also within it). In plain English this means that cylinders 1 and 4 are paired together and get spark at the exact same time and cylinders 2 and 3 are paired together. Example of unpaired cylinders would be: cylinders 1 and 3, or 2 and 4, or 1 and 2.
Let's examine your test results:
CASE 1: You got spark from all four spark plug wires. This is the correct test result and it indicates that the ignition coils and spark plug wires are OK.
The cause of your misfire condition is not due to a bad ignition coil. Go to: Other Possible Misfire Causes to see further tips and suggestions.
CASE 2: You got NO spark from only one spark plug wire. The next step is to check for spark directly on the coil pack tower that feeds that spark plug wire with spark. Go to: TEST 2: Testing For Spark At The Ignition Coil Pack.
CASE 3: You got NO spark from two spark plug wires that connect to paired cylinders 1 and 4. The next step is check for spark directly on the ignition coil towers (one at a time of course) that feed those spark plug wires, go to: TEST 3: Testing For Spark At The Ignition Coil Pack (Cylinders 1 And 4).
CASE 4: You got NO spark from two spark plug wires that connect to paired cylinders 2 and 3. The next step is check for spark directly on the ignition coil towers (one at a time of course) that feed those spark plug wires, go to: TEST 4: Testing For Spark At The Ignition Coil Pack (Cylinders 2 And 3).
CASE 5: You got NO spark from two spark plug wires that DO NOT connect to paired cylinders. The next step is to test each coil pack tower directly for spark one at a time. TEST 2: Testing For Spark At The Ignition Coil Pack.
CASE 6: You got NO spark from none of the spark plug wires. This usually indicates that the ignition coil is not getting power or that the crankshaft position sensor is bad.
Your next step is to make sure that the ignition coil is getting 10 to 12 Volts. For this test go to: TEST 5: Making Sure The Coil Pack Is Getting 12 Volts.
TEST 2: Testing For Spark At The Ignition Coil Pack
In this test step, you're gonna' test for spark directly on the ignition coil pack tower that connects to the spark plug wire that did not spark in TEST 1.
NOTE: This test section only applies if you got a no-spark test result from only one spark plug wire or no-spark from two spark plug wires that do not connect to paired cylinders (in TEST 1).
These are the test steps:
- 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 using a small piece of vacuum hose. It is important that you use this piece of vacuum hose! (see photo above).
- 3
Connect the spark tester with a battery jump start cable to the battery negative (-) terminal.
- 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.
Let's take a look at what your test results mean:
CASE 1: You got spark. This result lets you know that the ignition coil is good and that the spark plug wire is bad. Replace all of the spark plug wires as a 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.
