1. Verify Power and Ground:
* Battery Voltage: Check the battery voltage with a multimeter. It should be at least 12.6 volts when the engine is off and slightly higher when running. A low battery can cause intermittent or no spark.
* Ignition Switch: Ensure the ignition switch is supplying power to the ignition system. Use the multimeter to check for power at the appropriate ignition system wires when the key is in the "ON" position (but not cranking). The wiring diagram for your specific Ranger is crucial here to know which wires to check.
* Grounds: Corrosion on ground connections can disrupt the electrical flow. Check the grounds connecting the engine to the chassis, and the ground connections near the ignition module and coil. Clean and tighten them.
2. Crankshaft Position Sensor (CKP Sensor):
* This sensor tells the ignition module when to fire the spark. A faulty CKP sensor is a common cause of no spark.
* Location: Find its location (usually on the engine block near the crankshaft pulley).
* Testing: You'll need a multimeter or a diagnostic tool to test the sensor's output signal. A wiring diagram will show you how to do this. Often a simple visual inspection for damage is worthwhile first.
3. Camshaft Position Sensor (CMP Sensor) (if equipped): Some 2.3L engines may have a CMP sensor. This sensor provides the engine's rotational information to the computer. A fault here can affect spark timing or cause no spark in certain situations. The same testing methodology applies as with the CKP sensor.
4. Ignition Control Module (ICM):
* Even though you replaced it, it's worth double-checking:
* Installation: Ensure it's correctly seated and all connections are secure.
* Compatibility: Verify that the replacement ICM is the exact correct part number for your specific engine. There's a chance of a faulty replacement.
5. Pick-up Coil (in the distributor, if applicable):
* Your 1993 Ranger might have a distributor (some didn't). If it does, the pick-up coil inside the distributor generates the signal for the ignition module. If the distributor itself is faulty that would also cause a no-spark issue. The pick-up coil can be tested with a multimeter.
6. Wiring Harness:
* Check for broken, frayed, or corroded wires in the ignition system wiring harness. Pay close attention to the wires connecting the CKP sensor, CMP sensor (if applicable), ignition module, and coil.
7. PCM (Powertrain Control Module):
* In some cases, a faulty PCM can prevent the ignition system from functioning correctly. This is less likely, but it's possible. Diagnostic tools are usually necessary to test the PCM effectively.
Tools Needed:
* Multimeter
* Wiring diagram for your 1993 Ford Ranger 2.3L engine (this is absolutely essential)
* Socket wrench set
* Screwdrivers
* Wire brush or sandpaper for cleaning ground connections
Important Note: A wiring diagram specific to your 1993 Ford Ranger 2.3L is absolutely essential for proper testing. This diagram will show you the correct wire colors, connector locations, and test points for all the components mentioned above. You can usually find these diagrams online (some websites specialize in automotive repair manuals) or at a parts store.
If you've checked all of this and still have no spark, it's best to consult a qualified mechanic who has experience with these vehicles. They will have the tools and expertise to diagnose the problem more thoroughly.
