When your Dodge Caravan is having trouble starting, you can test and replace the spark plugs and ignition coil on a distributor system. If your Caravan is a newer model with a distributorless system, you can use a test light and scan tool to check the various components; however, an expert will need to perform the repairs.
- Skill level:
- Moderately Challenging
Other People Are Reading
Things you need
- Non-conductive ignition pliers
- Digital Volt/Ohmmeter
- Test light
- DRB scan tool
Examine the spark plugs outside the engine, one at a time. Check for cracks in their insulation around the tips and below the center electrodes. Replace any defective plugs.
Disengage each spark plug wire while the engine idles. The engine's performance should drop when a plug is removed. Something is wrong with the plug or wire if performance doesn't change.
Ground one plug's outer electrode to the engine block while inside its spark plug boot. Crank the engine and look for a strong blue spark across the electrodes. Repeat for the other plugs.
Remove the distributor cap and check the rotor if no spark was found. Make sure the rotor is turning while the engine cranks; replace it if it doesn't.
Disconnect the ignition coil wire from the distributor cap and hold the wire's end a quarter inch away from a good ground point. Check for a spark there while an assistant cranks the engine. Replace the wire if there's no spark.
Move the wire away from the ground point slowly. Look for arching at the coil tower. Replace the coil if this happens.
Distributor System Testing
Wait for the Caravan's engine to cool, unplug the electrical connector from the ignition coil pack, and connect an ohmmeter between the center pin and the pin to its left or right.
Check the coil's primary resistance. It should 0.45 to 0.65 ohms at 70 to 80 degrees F. Repeat this procedure for the pin on the other side (right or left).
Disconnect the spark plug wires from the coil's secondary towers. Measure the secondary resistance between the towers of each individual pack. It should be 10,900 to 14,700 ohms.
Detach the ignition coil harness connector and connect a test light device to the electrical connector's B+ terminal and ground. Turn the ignition switch to the "On" position. If the test light momentarily flashes, it's properly connected.
Crank the engine. If the light flashes momentarily, test the crankshaft position sensor with a DRB scan tool. If there's no flash, proceed to Step 6.
Unplug the crankshaft position sensor connector and re-crank the engine. Replace the crankshaft sensor if the light briefly flashed on the second crank. Scan for the camshaft position sensor if the light never flashed.
Distributorless System Testing
Tips and warnings
- Use non-conductive ignition pliers to hold anything like the ignition coil wire.
- Measure the battery voltage with a digital volt/ohmmeter before anything else. The voltage between the negative and positive battery terminals should be at least 12.66 volts.