TEST 3: Testing The Ignition Coil For Spark
In this test step, you'll test for spark directly on the ignition coil's tower. Since the ignition coil is inside the distributor, you'll need to remove the distributor cap.
Also, since the test is performed with the engine cranking, the distributor rotor will rotate, so be careful and take all necessary safety precautions. In the photo you'll notice the distributor rotor off the distributor for safety reasons.
Let's get testing:
Place the HEI spark tester directly on the ignition coil's tower.
Ground the HEI spark tester with the same battery jump start cable you have been using for the previous tests.
When all is ready, have your helper crank the engine as you hold the HEI spark tester in place.
Observe the HEI spark tester. You should see spark jump across its air gap.
You'll get one of the 2 results: (1) spark or (2) no spark.
Let's analyze your test results:
CASE 1: The spark tester sparked. This is the correct test result and confirms that the distributor cap is bad. Replace the distributor cap and rotor as a set and your no-start condition should be solved.
CASE 2: The spark tester DID NOT spark. Then further testing is required to see if the problem is due to a bad Nissan power transistor (ignition control module) or something else. Your next step is to go to: TEST 4: Ignition Coil's Power (12 V) Circuit.
TEST 4: Ignition Coil's Power (12 V) Circuit
If you've reached this point, it's because you've gotten a no-spark test result from all of the spark plug wires, the distributor cap and the ignition coil on your Nissan vehicle.
In this test step you're gonna' verify that the ignition coil is getting a good supply of juice (10 - 12 Volts DC).
NOTE: The photo above is of the Nissan Pathfinder's 2-wire connector. If your vehicle is not a Pathfinder (or QX-4), the colors of the wires will be different. This is no cause for concern because the circuit descriptions are the same.
Let's get started:
Select Volts DC mode on your multimeter.
With the red multimeter test lead probe the wire identified with the number 7 in the photo. This should be the Black with White stripe wire of the two wire distributor connector (the distributor has one 6 wire connector and a 2 wire connector).
Connect the black multimeter test lead to the battery (-) negative terminal.
Ask your assistant to turn the key ON with the engine Off.
You should see 12 Volts on the multimeter. Do you have 12 Volts?
Let's find out what your test result means:
CASE 1: Your multimeter displayed 12 Volts. This is the correct test result and it lets you know that the ignition coil is getting power.
The next step is to check that the ignition coil is being fed with a Switching Signal (activation signa) that comes from the power transistor. For this test go to: TEST 5: Testing The Ignition Coil's Switching Signal.
CASE 2: Your multimeter DID NOT display 12 Volts. Without power, the ignition coil will not fire spark.
Your next step is to find out why you're missing this voltage. Without this voltage the ignition control module (ICM) nor the ignition coil will work. Resolving this power issue should solve your no-start/no-spark problem.