How To Test The Ignition Coil And Power Transistor (1990-1995 3.0L Pathfindier And Pick Up)

TEST 4: Testing The Ignition Coil For Spark

If in TEST 3 the ignition coil's high tension wire DID NOT spark then the next step is to test for spark directly on the ignition coil's tower (see photo above).

If the ignition coil sparks, then you can conclude that the ignition coil's high tension wire is bad and that the spark plug wires need to be replaced as a set.

If the ignition coil DOES NOT spark then the next step is make sure that the ignition coil is getting 10 to 12 Volts DC (in TEST 5).

Let's get testing:

1. 1

   Place the HEI spark tester directly on the ignition coil's tower as shown in the photo above.

2. 2

   Connect the spark tester to the battery negative (-) terminal with a battery jump start cable.

3. 3

   Have your helper crank the engine as you hold the HEI spark tester in place.

4. 4

   The HEI spark tester should spark.

Let's analyze your test results:

CASE 1: The spark tester sparked. This is the correct test result.

You can conclude that the ignition coil's high tension wire is bad only if you have:

• Confirmed that all of the spark plug wires are not sparking (TEST 1).
• Confirmed that ignition coil's high tension wire does not spark (TEST 3).
• Confirmed that the ignition coil's tower does spark (TEST 4).

Replacing the spark plug wires as a set should solve the no-start problem on your 3.0L V6 Nissan Pathfinder (D21 or Pick Up).

CASE 2: The spark tester DID NOT spark. Then the next step is to make sure that the ignition coil is getting 10 to 12 Volts DC. For this test go to: TEST 5: Making Sure The Ignition Coil Is Getting 12 Volts.

TEST 5: Making Sure The Ignition Coil Is Getting 12 Volts

In this test section, we're gonna' make sure that the ignition coil is receiving 10 to 12 Volts DC.

The wire that feeds these 12 Volts to the ignition coil is the black with white stripe (BLK/WHT) wire of its electrical connector.

This wire is labeled with the number 2 in the photo above.

Let's get started:

1. 1

   Select Volts DC mode on your multimeter.

2. 2

   Disconnect the ignition coil from its electrical connector.

3. 3

   Turn the key ON but don't crank the engine.

4. 4

   Probe the female terminal (of the connector) that connects to the BLK/WHT wire.

5. 5

   Connect the black lead of the multimeter to the battery negative (-) terminal.

6. 6

   You should see 10 to 12 Volts on the multimeter.

Let's find out what your test result means:

CASE 1: 10 to 12 Volts are present in the BLK/WHT wire. This is the correct test result and it lets you know that the ignition coil is getting power.

Since the ignition coil does not fire spark, the next step is to check that the ignition coil is receiving an activation signal. This activation signal comes from the power transistor. For this test go to: TEST 6: Testing The Ignition Coil's Activation Signal.

CASE 2: 10 to 12 Volts ARE NOT present in the BLK/WHT wire. Without power the ignition coil will not fire spark.

This lack of spark will be caused by one of the following:

• An open-circuit problem in the BLK/WHT wire between the ignition coil's connector and the ignition switch.
• A defective ignition switch.