Making Sure The Connector Locking Tab Is Not Broken

Making Sure The Connector Locking Tab Is Not Broken. How To Test The Ford 4.6L, 5.4L Coil-on-Plug Ignition Coils

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.

COP COIL TEST 1: Checking For Spark

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

If you're just coming into this page and have not read the ‘First Things First’ subheading in the previous page, please do so now. If you have, well then, this a pretty straight forward test, but one that has to be done with the HEI spark tester. Here are a couple suggestions that'll help you to avoid wasting money and time (by not replacing a good part):

  1. 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.
  2. 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.
  3. I don't recommend using any other type of spark tester. Buy the HEI spark tester... 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' assume that you know which cylinder is the one that is misfiring or with the BAD ignition coil or coils (but, if you don't know which cylinder is the one, go to TEST 5), so the very first thing that has to be done is to:

  1. 1

    Remove the Coil-on-Plug ignition coil that you know or suspect is misfiring/BAD.

  2. 2

    Attach the HEI spark tester (or an equivalent spark tester) to the Coil-on-Plug ignition coil (as shown in the photos in the image viewer).

  3. 3

    Attach the HEI spark tester to a good Ground point by using a battery jump start cable (my preferred method).

  4. 4

    Have your helper crank the engine while you observe the spark tester. You're gonna' get one of two results: spark or No spark.

  5. 5

    After noticing the result, which will be either spark or no spark, disconnect the spark tester and put the ignition coil back in place.

  6. 6

    Repeat the test for all of the remaining Coil-on-Plug ignition coils.

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

CASE 1: If you got spark, from all of the Ford car or truck Coil-on-Plug ignition coils, then the ignition coils are good. The cause of the misfire is something else. Go to TEST 4.

CASE 2: If 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.

CASE 3: If 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: 4.6L, 5.4L Crank Sensor Test (this article is found at