How To Test The Ignition Coil (Ford 2.9L, 3.0L, 3.8L)

When the ignition whorl on your 2.9L, three.0L or 3.8L Ford V6 goes bad, your Ford is not gonna' offset and you might be left wondering if the problem is the ignition curlicue or the ignition command module. Well, in this article, I'm gonna' show you a very easy but very authentic way to find out if the ignition coil is bad or not.

The test that you're gonna' larn in this article is an on-machine exam of the ignition scroll done (in office) with the engine cranking. You won't be measuring the resistance of the ignition curlicue'southward Master or Secondary circuits. No sir, in my opinion this test (the Primary/Secondary resistance test) is a consummate waste of time and life that does not work around 99% of the time to diagnose a bad ignition coil.

Symptoms Of A Bad Ignition Coil

The well-nigh obvious symptom of a bad ignition coil on your ii.9L, 3.0L, 3.8L Ford machine, mini-van, or pickup is a no-start no-spark status.

Here are some more specific symptoms of a bad coil:

  1. The PCM (Powertrain Command Module = Fuel Injection Computer) will still pulse the fuel injectors.
    • This means that if you do a Noid light test, the Noid low-cal will flash ON and OFF.
    • And if the Noid light flashes ON and OFF, this indirectly tells yous that the creepo sensor is expert.
  2. The PCM volition still activate the fuel pump.
    • This can easily exist checked by hooking up a fuel pressure gauge to the Schrader valve (on the fuel injector rails) and checking the fuel pressure to see if it'due south at specification.
  3. The starter motor volition still crank the engine since the ignition whorl circuits don't have anything to practise with the starter motor circuits.

It's also bad the PCM is as well dumb to find out that the ignition curlicue has failed (and thus the cause of the no-commencement condition) simply it's actually not necessary, since the ignition scroll test is a pretty easy ane to practise and the accompanying symptoms (of a failed whorl) are easy to observe and/or examination.

IGNITION COIL Exam 1: Testing The Spark Plug Wire

How To Test The Ignition Coil (Ford 2.9L, 3.0L, 3.8L)

Even if you lot have already verified that you take a bonafide no-spark condition on your Ford car (pick upwardly or mini-van) yous need to start your ignition coil troubleshooting and tests here.

Y'all'll notice that I'll be asking you to use an HEI spark tester for the spark test and you may be wondering if you tin can utilize any other type of spark tester and the respond is aye yous can. The biggest reason I recommend the HEI spark tester is that information technology is a very, very accurate spark tester. In the section Why The HEI Spark Tester, I go more in depth almost this.

The very first affair that y'all need to do is make sure that the ignition whorl's high tension wire (the one that feeds the coil's spark to the distributor cap) is good or bad and this is what you lot'll demand to practise:

  1. i

    Disconnect the ignition coil'southward high tension wire from the distributor cap only but leave the other end connected to the ignition whorl'south tower.

  2. ii

    Now, on the stop that yous just unplugged from the heart of the distributor cap, Adhere the HEI spark tester (run across photo above).

  3. 3

    Using a bombardment jump kickoff cablevision, Ground the HEI spark tester to the battery negative (-) last.

  4. 4

    When you've finished setting up the spark tester, accept your helper creepo the engine (while yous observe the spark tester at a safety altitude).

  5. 5

    You'll get one of 2 results from the HEI spark tester: spark or no spark.

OK, let'southward have a look at what your exam results hateful:

CASE ane: You got spark. This means that the ignition ringlet and its high tension wire are good. The crusade of the no-start on your ii.9L, three.0L, or three.8L Ford car (or selection up, mini-van) is non due to a bad ignition coil.

CASE 2: You got NO spark:. This test result doesn't condemn the ignition coil or the high tension wire to the trash simply yet. The wire could be bad or the ignition gyre could non be receiving its switching signal from the ignition control module (ICM) or the coil could actually exist fried. The next step will help you to find out, go to: IGNITION Whorl TEST 2.