TEST 2: Making Sure The Ignition Coil Is Getting Power
The ignition coil needs power to function just like any other electrical component on your 4.2L Oldsmobile Bravada or 4.2L Buick Rainier.
This power is in the form of 10 to 12 Volts and is supplied to the ignition coil by the pink (PNK) wire (of the ignition coil's three-wire connector).
In the photo above, I've labeled the PNK wire with the letter A.
A simple multimeter test will confirm the presence or lack of these 10 to 12 Volts in the PNK wire.
Let's get started:
- 1
Disconnect the ignition coil from its electrical connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Connect the red multimeter test lead to the PNK wire of the electrical connector.
The PNK wire is labeled with the letter A in the image above. - 4
Ground the black multimeter test lead directly on the battery negative (-) terminal.
- 5
Turn the key on but don't crank or start the engine.
- 6
You should see 10 to 12 Volts DC displayed on your multimeter.
Let's examine your test results:
CASE 1: The non-sparking ignition coil is getting 10 to 12 Volts DC. This is the correct and expected test result and tells you the non-sparking ignition coil is getting power.
The next step is to check that the ignition coil is receiving Ground. For this test go to: TEST 3: Making Sure The Ignition Coil Is Getting Ground.
CASE 2: The non-sparking ignition coil is not getting 10 to 12 Volts DC. Without power the ignition coil is not going to spark.
The most common cause of this missing power is an open-circuit problem in the PNK wire.
Although it's beyond the scope of this tutorial to diagnose this problem, you have eliminated the ignition coil itself as the source of the misfire. Once power is restored to the ignition coil, it'll start to spark again.
TEST 3: Making Sure The Ignition Coil Is Getting Ground
In this test section, you'll check that the black (BLK) wire is supplying Ground to the ignition coil.
The Ground that the BLK wire supplies is a chassis Ground and is available at all times.
In the photo above, I've labeled the BLK wire with the letter C.
A simple multimeter voltage test will confirm the presence or lack of Ground in the BLK wire.
Let's get testing:
- 1
Disconnect the ignition coil from its electrical connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Connect the black multimeter test lead to the BLK wire of the ignition coil's connector.
The BLK wire is labeled with the letter C in the image above. - 4
Connect the red multimeter test lead directly on the battery positive (+) terminal.
- 5
You should see a voltage reading between 10 to 12 Volts DC on your multimeter.
NOTE: No need to turn the key to its ON position since this is a chassis Ground and Ground is present at all times.
Let's examine your test results:
CASE 1: The multimeter reported 10 to 12 Volts. This is the correct and expected test result and lets you know that the ignition coil is getting Ground.
The next step is to check that the ignition coil is getting an activation signal. For this test go to: TEST 4: Swapping Ignition Coils.
CASE 2: The multimeter DID NOT report 10 to 12 Volts. This test result confirms that the ignition coil is not receiving Ground. Without Ground, the ignition coil is not going to spark.
The most common cause of this missing Ground is an open-circuit problem in the BLK wire.
Although it's beyond the scope of this tutorial to diagnose this problem, you have eliminated the ignition coil itself as the source of the misfire. Once Ground is restored to the ignition coil, it'll start to spark again.
