TEST 2: Making Sure The Crank Angle Sensor Is Getting Ground
Now that you've made sure that the crank angle sensor is getting 10 to 12 Volts, the next step is to make sure that it's getting Ground.
The wire that supplies the crank angle sensor with Ground, is the black (BLK) wire of the distributor's 4-wire connector.
This BLK wire connects to the terminal labeled with the number 4 in the photo above.
These are the test steps:
- 1
Set your multimeter to Volts DC mode.
- 2
Disconnect the 4 wire connector from the distributor.
- 3
Probe the terminal labeled with the number 4 with the black multimeter test lead.
- 4
Connect the red multimeter test lead directly on the battery positive (+) terminal.
- 5
Your multimeter should register 10 to 12 Volts DC.
Let's examine your test result:
CASE 1: Your multimeter registered 10 to 12 Volts. This is the correct test result and confirms that the crank angle sensor is getting Ground.
The next step is to make sure that the crank angle sensor is producing a 180° REF signal. For this test go to: TEST 3: Verifying The 180° REF Signal.
CASE 2: Your multimeter DID NOT register 10 to 12 Volts. Without Ground the crank angle sensor will not function.
Your next step is to repair this Ground wire and retest.
TEST 3: Testing The 180° REF Signal
If you've reached this point, then you've checked and confirmed that the crank angle sensor is getting 12 Volts and Ground.
We're now going to check that the crank angle sensor is producing a 180° REF signal.
We'll use an LED light to check for the presence of the 180° REF signal. Also, we're gonna' turn the engine by hand instead of using the starter motor.
The wire that we're gonna' connect the LED light to is the green with yellow stripe (GRN/YEL) wire of the distributor's engine wiring harness connector (see photo above).
NOTE 1: The distributor must remain connected to its 4-wire electrical connector for this test to function. You'll need to use a back probe or a wire piercing probe to connect the LED light to the GRN/YEL 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. Don't use the starter motor to test for the 180° REF signal. You can accomplish this by turning the crankshaft pulley with a 1/2" ratchet and the appropriate socket.
IMPORTANT: As a safety precaution, remove the fuel pump fuse before starting this test.
OK, these are the test steps:
- 1
Reconnect the distributor to its engine wiring harness connector.
- 2
Remove the fuel pump fuse.
- 3
Locate the GRN/YEL wire of the 4-wire distributor connector.
- 4
Connect the red lead of the LED light to the GRN/YEL wire with the appropriate tool.
IMPORTANT: The distributor must remain connected to its electrical connector. - 5
Connect the black lead of the LED light to the battery negative (-) terminal.
- 6
Turn the key ON but don't crank the engine.
The LED light may turn ON or may stay OFF at this point. Don't worry about this and continue to the next step. - 7
Slowly turn the engine by hand using the appropriate tools on the crankshaft pulley.
- 8
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 180° REF signal is present.
The next step is to test the 1° POS signal. For this test go to: TEST 4: Verifying The 1° POS Signal.
CASE 2: The LED light DID NOT flash ON and OFF as you turned the crankshaft pulley. This test result tells you that the crank angle sensor is not producing the 180° REF signal.
You can conclude that the crank angle sensor is bad if you have confirmed that:
- The ignition coil does not spark.
- The ignition coil is not receiving an activation signal.
- The power transistor is not receiving an activation signal.
- The crank angle sensor is getting 10 to 12 Volts.
- The crank angle sensor has Ground.
- The crank angle sensor is not creating a 180° REF signal.
