TEST 3: Checking The Switching Signal For Cylinders 6 and 1
OK, in TEST 2: Checking For Directly On The Coil Tower you found out that the towers that feed cylinders #6 and #1 are not sparking.
Recall that cylinders #6 and #1 are ‘Paired’ and as such, these get spark at the exact same time from the same ignition coil (within the pack).
In this test step, you're gonna' check that the switching signal for these two cylinders (#6 and #1) is being fed to the coil pack.
If this switching signal is present, then you'll know beyond a shadow of a doubt that the coil pack is bad. To test for this switching signal, you'll need an LED light. To see an example of this took, click here: LED Light Tool (at: easyautodiagnostics.com).
Alright, this is what you'll need to do:
- 1
Using the illustration above as a guide, probe the wire that connects to the passenger side coil pack male terminal labeled with the number 1.
You can test this circuit with the coil pack connected to the connector or not, but do not test the front of the connector or you could damage the terminal (and believe me, you don't want this to happen). - 2
Attach the BLACK lead of the LED light to the circuit and connect the RED lead directly on the battery positive (+) terminal.
- 3
When ready, have your helper crank the engine as you watch the LED light.
- 4
As the engine cranks, you'll get one of two results: either the LED light will blink ON and OFF the whole time the engine is cranking or it will NOT blink ON and OFF when the engine is cranking.
OK, let's take a look at what your results mean:
CASE 1: The LED light blinked ON and OFF during engine cranking. This is the correct result and tells you that the coil pack is fried. Replacing the coil pack will solve the no-spark condition for cylinders #6 and #1.
Here's why: If the ignition coil within the coil pack that feeds cylinders #6 and #1 is getting the switching signal, it has to spark. Since you have confirmed the switching signal's presence, by a process of elimination you now know the coil pack is bad.
CASE 2: The LED light DID NOT blink ON and OFF during engine cranking. Double check your connections and repeat the test, if still no blinking then the coil pack is not the cause of the problem. Without the switching signal, the ignition coil that controls these two towers will not spark.
If your vehicle has an ignition control module (ICM), then the most likely cause is that the ICM is bad. If your vehicle does not have an ICM, this means the coil pack is controlled directly the PCM (Powertrain Control Module= Fuel Injection Computer) and the PCM is probably fried. Testing both of these condition is beyond the scope of this article, but you have at least eliminated the spark plug wires and coil pack as the cause of the no spark condition.
TEST 4: Checking The Switching Signal For Cylinders 3 and 5
OK, in TEST 2: Checking For Directly On The Coil Tower you found out that the towers that feed cylinders #3 and #5 are not sparking. In this test step, you're gonna' check that the switching signal for these two cylinders (#3 and #5) is being fed to the coil pack.
If this switching signal is present, then you'll know beyond a shadow of a doubt that the coil pack is bad. To test for this switching signal, you'll need an LED light. To see an example of this took, click here: LED Light Tool.
Alright, this is what you'll need to do:
- 1
Using the illustration above as a guide, probe the wire that connects to the passenger side coil pack male terminal labeled with the number 3.
You can test this circuit with the coil pack connected to the connector or not, but do not test the front of the connector or you could damage the terminal (and believe me, you don't want this to happen). - 2
Attach the BLACK lead of the LED light to the circuit and connect the RED lead directly on the battery positive (+) terminal.
- 3
When ready, have your helper crank the engine as you watch the LED light.
- 4
As the engine cranks, you'll get one of two results: either the LED light will blink ON and OFF the whole time the engine is cranking or it will NOT blink ON and OFF when the engine is cranking.
OK, let's take a look at what your results mean:
CASE 1: The LED light blinked ON and OFF during engine cranking. This is the correct result and tells you that the coil pack is fried. Replacing the coil pack will solve the no-spark condition for cylinders #3 and #5.
Here's why: If the ignition coil within the coil pack that feeds cylinders #3 and #5 is getting the switching signal, it has to spark. Since you have confirmed the switching signal's presence, by a process of elimination you now know the coil pack is bad.
CASE 2: The LED light DID NOT blink ON and OFF during engine cranking. Double check your connections and repeat the test, if still no blinking then the coil pack is not the cause of the problem. Without the switching signal, the ignition coil that controls these two towers will not spark.
If your vehicle has an ignition control module (ICM), then the most likely cause is that the ICM is bad. If your vehicle does not have an ICM, this means the coil pack is controlled directly the PCM (Powertrain Control Module= Fuel Injection Computer) and the PCM is probably fried. Testing both of these condition is beyond the scope of this article, but you have at least eliminated the spark plug wires and coil pack as the cause of the no spark condition.
