TEST 4: Making Sure The Ignition Coil Is Getting Power
If you've reached this point, you have:
- Confirmed that none of the four spark plug wires are delivering spark (TEST 1).
- Confirmed that the ignition coil is not sparking (TEST 3).
In this test section, we're gonna' make sure that the ignition coil is getting power (12 Volts).
The wire that delivers these 12 Volts is the black with white stripe (BLK/WHT) wire of the distributor's 7-wire connector.
In the photo above, the BLK/WHT wire connects to the terminal I've labeled with the letter G.
These are the test steps:
- 1
Disconnect the distributor from its 7-wire connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Connect the black multimeter test lead to the battery negative (-) post.
- 4
Turn the key to the ON position but don't crank or start the engine.
- 5
With the red multimeter test lead, gently probe the female terminal labeled with the letter G in the photo above.
The terminal labeled with the letter G connects to the black with white stripe (BLK/WHT) wire of the distributor's 7-wire connector. - 6
Your multimeter should register 10 to 12 Volts DC.
Let's take a look at your test result:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct test result.
The next test is to see if the ignition coil is getting an activation signal. For this test go to: TEST 5: Testing The Ignition Coil's Activation Signal.
CASE 2: The multimeter DID NOT register the indicated voltage. Without power, the ignition coil will not spark.
Your next step is to check the Engine fuse in the under-dash fuse box and see if it's blown. If it's blown, replace it and retest.
TEST 5: Testing The Ignition Coil's Activation Signal
IMPORTANT: If you got a spark result in TEST 3, do not proceed with this test step, or you risk damaging the ignition coil. A spark result in TEST 3 confirms that the ignition coil's activation signal is present.
In this test section, we're gonna' make sure that the ignition coil is getting an activation signal.
This activation signal is provided by the ignition control module located inside the distributor.
We'll verify the presence of the ignition coil's activation signal with an LED light and while the engine is being cranked.
NOTE: This test must be done with the distributor connected to its connector. You'll need to use a back probe on the connector or a wire piercing probe on the wire. You can see an example of this tool and where to buy it here: Wire Piercing Probe.
These are the test steps:
- 1
Reconnect the distributor to its 7-wire connector.
- 2
Connect the black lead of the LED light to the white (WHT) wire of the 7-wire connector.
In the photo above, the WHT wire connects to the female terminal I've labeled with the letter F.
NOTE: The distributor must remain connected to its 7-wire connector. You'll need to back probe the connector or use a wire piercing probe on the wire. - 3
Connect red wire (lead) of LED light to the battery (+) positive terminal.
It's important that it be connected at the battery positive (+) terminal. - 4
Have an assistant crank the engine.
- 5
The LED Light should blink ON and OFF the whole time the engine is being cranked.
NOTE: Don't worry about what the LED Light does before or after your helper starts cranking the engine. The only results you're interested in interpreting are the results obtained with the engine cranking.
Let's examine your test result:
CASE 1: The LED light flashed ON and OFF. This is the correct test result.
With this test result you can conclude that the ignition coil is bad and needs to be replaced if you have:
- Confirmed that none of the four spark plug wires are sparking (TEST 1).
- Confirmed that the ignition coil's tower is not sparking (TEST 3).
- Confirmed that the ignition coil is getting power (TEST 4).
- Confirmed, in this test section, that the ignition coil is getting an activation signal.
With this test result you can also conclude that the ignition control module is good.
Replacing the ignition coil will solve your no-spark/no-start condition. The only thing that sucks is that at the time of this writing, you cannot buy the ignition coil separately since you have to buy the whole distributor.
CASE 2: The LED DID NOT flash ON and OFF. Without an activation signal, the ignition coil will not spark.
Re-check all of your connections and repeat the test. If the LED light still does not flash ON and OFF, then the next step is to make sure that the ignition control module is getting Ground. For this test go to: TEST 6: Making Sure The Ignition Control Module Is Getting Ground.
