Here's a breakdown of how to test the key components:
1. Check for Spark: This is the most crucial test. You'll need a spark tester or a gap-bridging tool (easily made with a spare spark plug wire and a suitable non-conductive spacer like a piece of rubber tubing).
* Method: Remove a spark plug (usually easiest from the #1 cylinder). Attach the spark tester to the spark plug wire. Ground the spark tester metal clip to the engine block. Have someone crank the engine while you observe the spark tester. A strong, blue spark indicates a good ignition system. A weak or absent spark points to problems further down the line.
2. If No Spark: If you didn't get a spark, systematically check these components:
* Crank Sensor (Crankshaft Position Sensor): This sensor tells the PCM (Powertrain Control Module) when to fire the spark plugs. Testing requires a multimeter and accessing the sensor's connector. You'll need a wiring diagram to identify the correct wires and check for continuity and resistance according to the specifications in a Ford repair manual or online resource specific to your Ranger's engine (2.5L, 3.0L, or 4.0L). A faulty crank sensor often leads to a no-start condition.
* Cam Sensor (Camshaft Position Sensor): Similar to the crank sensor, it tells the PCM the position of the camshaft. Again, testing requires a multimeter and a wiring diagram. Check for continuity and resistance values.
* Ignition Coil: This boosts the low voltage from the ignition system to the high voltage needed for sparking. You can visually inspect the coil for cracks or damage. More accurate testing involves using a multimeter to check its resistance (refer to the specifications in a repair manual). You can also try swapping the coil with one from a known good vehicle (if you have access to one) to isolate it as the problem.
* Ignition Control Module (ICM) or PCM (Powertrain Control Module): These control the ignition system. These are more difficult to test yourself and often require professional diagnostic tools to accurately diagnose issues. If all other components check out, these should be suspected.
* Ignition Switch: A faulty ignition switch might not be sending power to the ignition system. This is less common but possible.
* Wiring: Check all the wiring harnesses connected to the above components for any broken, frayed, or corroded wires. A visual inspection and continuity testing with a multimeter is necessary.
3. If Weak Spark: A weak spark can be caused by:
* Worn spark plugs: Replace them.
* Worn or damaged spark plug wires: Inspect for cracks, damage, or poor connections.
* Low battery voltage: Check your battery voltage.
Important Notes:
* Repair Manual: A repair manual specific to your 2000 Ford Ranger (including the engine type) is invaluable. It contains wiring diagrams, component locations, and testing specifications.
* Multimeter: A multimeter is essential for testing the electrical components.
* Safety: Remember to disconnect the negative battery terminal before working on the ignition system.
* Professional Diagnosis: If you are not comfortable working on your vehicle's electrical system, take it to a qualified mechanic for diagnosis and repair.
Testing the ignition system requires systematic troubleshooting. Start with the spark test, then work your way through the components one by one. Always consult a repair manual for your specific vehicle and engine.
