Ford Ranger Maintaince And Repair Manual page 189

3. Crank the engine and check for spark.
4. Turn the ignition switch OFF.
5. If a spark did occur, measure the resistance of the ignition coil wire, replace it if the resistance is
greater than 7000 ohms per foot. If the readings are within specification, replace the ignition coil.
6. If no spark occurs, the problem is not the coil.
Ignition Coil Supply Voltage
1. Remove the/coil connector.
2. Attach the negative (−) lead from a Volt/ohmmeter to the distributor base.
3. Measure the battery voltage.
4. Turn the ignition switch to the RUNposition.
5. Measure the voltage at the positive (+) terminal of the ignition coil. If the reading is at least 90% of
battery voltage, check the ignition coil connector for dirt, corrosion and damage. Check the ignition
coil terminals for dirt, corrosion and damage; if no problem is found, replace the ignition coil. If the
reading is less than 90% of battery voltage, check the wiring between the ignition coil and ignition
switch, or for a worn or damaged ignition switch.
178
HOW TO USE THIS BOOK
Secondary coil wire test 7 chart
Click to enlarge
TESTING