IGNITION COIL TEST 1: Testing For Spark With A Spark Tester
If you haven't done so already, the very first thing you need to do is to see if the ignition coil is sparking.
The test instructions below call for using an HEI spark tester and you may be wondering if you can use any other and the answer is yes you can. The biggest reason I recommend the HEI spark tester is that it is very, very accurate spark tester. In the section Why The HEI Spark Tester, I go more in depth about this.
OK, even if you already know that you have a no spark condition, follow the test steps since the purpose of this very first ignition coil test, is to see if the ignition coil high tension wire (the one that feeds the coil's spark to the distributor cap) is good or bad.
OK, this what you need to do:
- 1
Disconnect the ignition coil's high tension wire from the distributor cap but leave the end that connects to the ignition coil connected.
- 2
Now, on the end that connects to the center of the distributor cap, attach the HEI spark tester (see photo in image viewer).
- 3
Using a battery jump start cable, Ground the HEI spark tester to the battery negative (-) terminal.
- 4
When everything is set, have a helper crank up the engine while you observe the spark tester from a safe distance.
- 5
The HEI spark tester will give you one of two results: spark or no spark.
OK, let's take a look at what your test results mean:
CASE 1: You got spark. This spark test result means that the ignition coil and its high tension wire are good and not the cause of your Ford pick up's (or van or SUV) no-start condition.
Since the ignition coil's job is to create spark and your spark tester has confirmed that the ignition coil is sparking, then you can eliminate the ignition coil as defective. The following tutorial will provide you with other diagnostic/troubleshooting ideas to solve your Ford's no-start condition:
CASE 2: You got NO spark. This test result tells you that something is wrong but doesn't condemn the ignition coil or the high tension wire as bad just yet.
The wire could be bad or the ignition coil could not be receiving its switching signal from the ignition control module or the coil could really be fried. Now, don't worry, this article will help you find out, go to: IGNITION COIL TEST 2: Testing For Spark Directly On Coil's Tower.
IGNITION COIL TEST 2: Testing For Spark Directly On Coil'S Tower
In this test step, you're gonna' test for spark directly on the ignition coil and thus bypass the coil's high tension wire.
This spark test result will let you know if the high tension cable is bad and not letting spark thru' to the distributor cap (this happens quite a bit) or will let you know that you need to continue to the next test.
If spark is present directly on your Ford's coil's tower, then you can conclude that the coil's high tension wire is bad and needs to be replaced (along with all of the spark plug wires).
If spark is not present, then the next step is to make sure that the coil is getting power and the switching signal from the ignition module.
Alright, this is what you'll need to do:
- 1
OK, disconnect the high tension wire from the ignition coil.
- 2
Now, connect the HEI spark tester to the ignition coil's tower using a small piece of vacuum hose. This is important, see how I've done it in the photo in the image viewer.
- 3
Now Ground the spark tester using a battery jump start cable directly on the battery negative (-) terminal.
- 4
When ready have your helper crank the engine as you eyeball the HEI spark tester, you'll see one of two results: spark or no spark.
OK, let's take a look at what your test results mean:
CASE 1: You got spark. This spark test result tells you that the high tension wire is FRIED and is the cause of your no-start condition. Replace all of the spark plug wires as a set.
This is a very common problem (the coil wire not transmitting spark) due to the simple fact that spark plug wires don't last forever and if this the case, in your particular case, then there's a good chance that your Ford's spark plug wire set is 3 years or older.
If you want to save a few bucks buying the factory original Motorcraft spark plug wires, take a look at the following section: Where To Buy The Ignition Coil And Save.
CASE 2: You got NO spark. This spark test result eliminates the high tension wire and means you're getting closer to the actual cause of the ignition coil's no spark condition.
The next step is to verify that the ignition control module (ICM) is activating the ignition coil. For this test, go to: IGNITION COIL TEST 3: Verifying Ignition Coil Is Getting 12 Volts.
