How To Test The Ford 4.6L, 5.4L Coil-On-Plug Ignition Coils

If you've been wondering how to test the Coil-On-Plug ignition coils on your Ford car or truck (with a 4.6L or 5.4L V8) to see if one or several are bad and are causing a misfire, this is the article for you.

As is the custom here at easyautodiagnostics.com, the tests steps are explained in detail and the diagnostic/troubleshooting is accomplished in several easy steps.

OK, before we jump into the COP coil tests, let me just make you aware where you can find a complete list of 4.6L and 5.4L ‘How To Test’ articles that are located in this website and at troubleshootmyvehicle.com and this list is found here: Ford 4.6L, 5.4L Index Of Articles.

One last thing, I have written another 4.6L, 5.4L COP coil article that is a little leaner than this one, you can take a look at it here: Ford 4.6L, 5.4L Coil-On-Plug Misfire Tests (this article is located at troubleshootmyvehicle.com).

You can find this tutorial in Spanish here: Pruebas: Bobinas De Encendido Individuales (COP) -4.6L, 5.4L Ford (at: autotecnico-online.com).

Common Symptoms Of A Bad Ford Coil-On-Plug Ignition Coils

This is not the most definitive list on the subject, but does cover the majority of symptoms I've seen on this type of ignition system:

1. Misfire codes that light up the check engine light (CEL) on your instrument cluster.
2. Misfire codes: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308.
3. Engine misfire that DOES NOT light up the check engine light (CEL).
4. Smell of unburned gasoline coming out of the tailpipe.
5. Rotten egg smell coming out of the tailpipe. This is due to the unburned gasoline from the misfiring cylinder over loading the catalytic converter.
6. Really bad gas mileage.
7. Lack of power as you accelerate the vehicle down the road.

What Tools Do I Need?

A scan tool (automotive diagnostic scanner) isn't needed to test the COP ignition coils on your Ford car or truck. The tests you're about to learn are all done without one. Now, what if you don't know which cylinder is the one misfiring? Don't you need a scan tool to find out? Well no, you can find out which one it is without a scan tool. You can perform the cylinder balance test yourself on your Ford car or truck, Test 5 will help you with this. You'll need:

1. An HEI spark tester.
   • This inexpensive spark tester is a MUST have tool to be able to correctly diagnose the Coil-On-Plug ignition coils on your Ford (or Mercury or Lincoln) vehicle with the info/tests in this article (don't have an HEI spark tester? Need to buy one? You can buy it here: OTC 6589 Electronic Ignition Spark Tester).
2. Battery jump start cables.
3. LED light.
   • To see what one looks like, click here: Abe's LED Light tool.
4. A helper.
   • You'll need someone to help you crank the engine while you perform the tests in the engine compartment.
5. A repair manual.
   • For whatever remove and replace info you'll need that is not covered by this article.

Circuit Descriptions Of The C-O-P Ignition Coil Connector

OK, to test the Coil-On-Plug ignition coils on your Ford car or truck, you need to know what each wire (circuit) does in the connector. Here are the circuit descriptions:

• Circuit labeled 2:
  • Power (12 V) Circuit.
• Circuit labeled 1:
  • Switching Signal Circuit.

You don't need to know the color of the wires for this test since the circuit descriptions (above) are shared by all of the eight Coil-On-Plug ignition coils on your Ford car or truck. So, whether you're testing the number 1 cylinder ignition coil or the number 4 cylinder ignition coil (or whichever ignition coil), the above info applies.

To test these circuits, it's not necessary to unplug the ignition coil's connector. What I recommend you do is to test for each signal with the connector connected using a wire-piercing probe. This is the easiest and the most effective way of getting at the signals. If you need to see what this tool looks like, click here: Wire-Piercing Probe.

Where To Buy The Ignition Coil And Save

The following links will help you comparison shop for the ignition coils:

Not sure if the ignition coils above fit your particular Ford vehicle? Don't worry, once you get to the site, they'll make sure they fit and if they don't, they'll find you the right ones.

Making Sure The Connector Locking Tab Is Not Broken

Before jumping into the tests, you'll need to first check that all of the Coil-On-Plug (COP) ignition coil connectors on your Ford car or truck are not broken and thus securely attached to their respective ignition coils.

Broken? What I mean is this: Each connector has a plastic tab that locks the connector in place (onto the ignition coil). This locking tab prevents the connector from un-plugging itself from the ignition coil. And this tab breaks easily.

Normally after someone has disconnected the ignition coil to replace it or replace the spark plug or replace whatever necessitates the ignition coil to be removed from its place.

This is a very common problem/cause of a misfire condition on these Ford COP ignition systems. This is what could be causing your misfire problem and you can check this by gently pulling on all of the ignition coil connectors (without pressing their locking tab) to see if they'll come un-plugged.

If it comes un-plugged, well then you have found a problem that could very well be the cause of your misfire condition. Repair it before continuing with the rest of the tests. If you do need to buy some of these connectors, you can buy them here: PICO 5713PT FORD Ignition Coil-2.

TEST 1: Checking For Spark

Checking the ignition coils for spark a pretty straight forward test, but one that has to be done with a dedicated spark tester. Here are a couple suggestions that'll help you to avoid wasting money and time (by not replacing a good part):

• Do not use a regular spark plug instead of a dedicated spark tester. Using a spark plug (instead of a spark tester) is the surest way to chase a ghost that'll have you spending your hard earned money on parts the car does not need.
• Pulling the ignition coil off of its spark plug, as the engine is running, to see/hear if it's sparking is a major NO NO. A lot of folks do this and swear by it as being effective, nothing could be further from the truth. This method can ruin/fry the ignition coil and now you've got another problem on your hands.
• I don't recommend using any other type of spark tester. Buy the HEI spark tester and not an imitation or something similar (don't have an HEI spark tester? Need to buy one? You can buy it here: OTC 6589 Electronic Ignition Spark Tester).

OK, now on with the show, I'm gonna suggest that you test all ignition coils for spark (although you don't have to). I do this myself just to make sure I'm getting the most accurate results from my diagnostic.

If you know which cylinder is the one that's misfiring or you have done a cylinder balance test and have identified the 'dead' cylinder (TEST 5: Doing A Cylinder Balance Test), then you can just test the ignition coil that belongs to the 'dead' cylinder.

1. 1

   Remove the ignition coil from its place on the engine.
   
   NOTE: It may be necessary to unplug the ignition coil from its 2-wire connector to remove it. If so, be sure and reconnect it to continue on to step 2.

2. 2

   Attach the HEI spark tester (or an equivalent spark tester) to the ignition coil (as shown in the photo above).

3. 3

   Ground the HEI spark tester directly on the battery negative (-) post with a battery jump start cable.

4. 4

   Have your helper crank the engine while you observe the spark tester.

5. 5

   You're gonna' get one of two results: spark or no spark.

6. 6

   Disconnect the spark tester and put the ignition coil back in place.

7. 7

   Repeat the test for all of the remaining ignition coils.

Let's take a look at what your test results mean:

CASE 1: You got spark from all of the Ford car or truck Coil-On-Plug ignition coils. This result tells you that the ignition coils are good. The cause of the misfire is something else.

Your next step is to go to: TEST 4: Checking For Leaking Oil/Anti-Freeze.

CASE 2: You got spark from some but NOT all of the Ford car or truck Coil-On-Plug ignition coils. Then the ones that did not fire off spark are probably bad.

To make sure you need to verify that the ignition coil (the one that did not spark) is receiving 12 Volts and the Switching signal. Go to: TEST 2: Checking For Battery Power.

CASE 3: You got NO spark from none of the Ford car or truck Coil-On-Plug ignition coils. Then the cause of your Ford's no-start condition is not due to the ignition coils.

It is rare (next to impossible) for all of the ignition coils to go bad at the exact same time. Testing this condition is beyond the scope of this article but possible causes could be a bad crankshaft position sensor, bad ignition switch, etc.

If you need to test the crank sensor, here's where you can find the test article: How To Test The Crankshaft Position Sensor (Ford 4.6L, 5.4L) (this tutorial is found at: troubleshootmyvehicle.com).