TEST 8: Verifying The Activation Signal For Cylinders 2 And 3
In this test step, you're going to verify that the individual ignition coil (within the coil pack) that fires spark to cylinders 2 and 3 is getting its activation signal from the fuel injection computer.
If you're testing the primary coil pack, you'll be testing the tan with orange stripe (TAN/ORG) wire of the primary ignition coil pack's electrical connector.
If you're testing the secondary coil pack, you'll be testing the tan with light blue stripe (TAN/LT BLU) wire of the secondary ignition coil pack's electrical connector.
NOTE: To check for the ignition coil's activation signal, you'll need to use an automotive LED light. You can see an example of this tool here (and how to make one): The LED Light Test Tool And How To Make One.
WIRING DIAGRAM: You can find the ignition system wiring diagram here: Ignition System Circuit Diagram (1998-2001 2.5L Ford Ranger).
Alright, let's get testing:
With an appropriate tool, connect the black lead of the LED light to the 2/3 activation signal wire.
If you're testing the primary ignition coil pack, this wire is the TAN/ORG wire.
If you're testing the secondary ignition coil pack, this is the TAN/LT BLU wire.
Connect the red lead of the LED light to the battery positive (+) terminal.
Have your helper crank and start the engine.
The LED light will flash ON and OFF, the whole time the engine is cranking and running if the activation signal is present.
Let's find out what your test result means:
CASE 1: The LED light flashed ON and OFF. With this test result you can conclude that the fuel injection computer is providing the activation signal that the ignition coil needs to start firing spark to cylinders 2 and 3 and the circuit is OK.
This test result confirms that the ignition coil pack is defective (and needs to be replaced) only if you have confirmed that coil towers for cylinders 2 and 3 are not firing spark.
CASE 2: The LED light DID NOT flash ON and OFF. This test result tells you that the ignition coil that fires spark to cylinders #2 and #3 is not getting its activation signal.
This usually means that the signal wire has an open-circuit problem between the connector or the computer or the computer is fried (altho' this is a very rare condition).
With this result you have eliminated the coil pack as the source of the misfire condition.
More 2.5L Ford Ranger Tutorials
You can find a complete list of tutorials here: Ford 2.5L Index Of Articles.
Here's a sample of the tutorials you'll find there:
- Ignition System Circuit Diagram (1998-2001 2.5L Ford Ranger).
- Oxygen Sensor Circuit Diagram (1998-2001 2.5L Ford Ranger).
- How To Test The Front O2 Sensor Heater (1998-2001 2.5L Ford Ranger).
- Rear O2 Sensor Heater Test (1998-2001 2.5L Ford Ranger).
If this info really saved the day, buy me a beer!