TEST 4: Testing The 1° POS Signal
For our last test we're gonna' test for the presence of the 1° POS signal in the green with black stripe (GRN/BLK) wire.
We will use the LED light to test for the signal's ON/OFF pulses. One thing to note is that the ON/OFF flashes of the LED light will be very rapid.
It's very important that you enlist a helper to help you turn the crankshaft pulley very slowly so that you can see the LED light flashes.
NOTE 1: The distributor must remain connected to its 4-wire electrical connector for this test to function. You'll need to use a wire piercing probe to connect the LED light to the signal wire. You can see an example of this tool here: Wire Piercing Probe.
NOTE 2: This test requires that you turn the engine by hand (with the appropriate tools). Don't use the starter motor to test for the 1° POS signal.
IMPORTANT: The fuel pump fuse must be removed before attempting this test. You can find the location of the fuel pump fuse here: Fuel Pump Fuse Location
OK, these are the test steps:
Locate the GRN/BLK wire that connects to the female terminal labeled with the number 4 in the photo above.
Connect the red lead of the LED light to the GRN/BLK wire. You'll need to use a tool to pierce the wire and then connect the LED light to this tool.
IMPORTANT: The distributor must remain connected to its electrical connector.
Connect the black lead of the LED light to the battery negative (-) terminal.
Turn the key ON but don't crank the engine.
The LED light will probably turn ON and this is normal. If the LED does not turn ON, don't worry and continue to the next step.
Slowly turn the crankshaft pulley by hand using the appropriate tools.
NOTE: It's important that you turn the crankshaft pulley as slowly as you possible can so that you can see the ON/OFF flashes of the LED light.
The LED light should flash ON and OFF as you turn the engine by hand.
Let's analyze your test result:
CASE 1: The LED light flashed ON and OFF as you turned the crankshaft pulley. This is the correct test result and confirms that the 1° POS signal is present.
CASE 3: The LED light DID NOT flash ON and OFF as you turned the crankshaft pulley. This test result tells you that the camshaft position sensor is not producing the 1° POS signal.
You can conclude that the camshaft position sensor is bad if you have confirmed that:
- The ignition coil does not spark.
- The BLK/WHT wire is supplying 10 to 12 Volts to the cam sensor.
- The BLK wire is supplying Ground to the cam sensor.
- The camshaft position sensor is not creating a 120° REF signal.
Since the camshaft position sensor isn't sold separately, you'll need to replace the distributor.
Where To Buy The Distributor And Save
The distributor on your 3.0L V6 Nissan Pathfinder or Pick Up isn't an inexpensive component. Check out the following links and compare prices, I think they'll save you a few bucks:
The distributors in the links above fit the following vehicles:
- 3.0L V6 Nissan Pathfinder: 1990, 1991, 1992, 1993, 1994, 1995.
- 3.0L V6 Nissan D21 Pick Up: 1990, 1991, 1992, 1993.
- 3.0L V6 Nissan Pick Up: 1994, 1995.
More 3.0L Nissan Tutorials
You can find a complete list of tutorials in this index: Nissan 3.0L Index of Articles.
Here's a small sample of the 3.0L Nissan tutorials you'll find in the index:
- How To Test Engine Compression (3.0L Nissan).
- Mass Air Flow (MAF) Sensor Test 3.0L Nissan Quest (1993, 1994, 1995).
- Mass Air Flow (MAF) Sensor Test 3.0L Nissan Maxima (1995-1999).
- How To Test The Starter Motor (Nissan 3.0L, 3.3L) (at: troubleshootmyvehicle.com).
- How To Test Engine Compression (Nissan 3.0L, 3.3L, 3.5L) (at: troubleshootmyvehicle.com).
If this info really saved the day, buy me a beer!