TEST 6: Testing The Ignition Coil's Activation Signal
The ignition coil gets an activation signal from your 5.2L V8 Dodge Dakota's fuel injection computer.
The ignition coil terminal that receives this activation signal is the one labeled with the (-) symbol. A black with gray stripe (BLK/GRY) wire connects to the (-) terminal.
To test the presence of this signal (while we crank the engine), we're gonna' use a 12 Volt automotive test light.
Let's get started:
Connect the alligator clip of the 12 Volt test light to the battery positive (+) terminal.
Touch the ignition coil's terminal with the (-) symbol with the tip of your 12 Volt test light's metal probe.
The wire that connects to the (-) terminal of the ignition coil should remain connected to the terminal.
Have an assistant crank the engine while you maintain the 12 Volt test light's probe touching the (-) terminal.
The 12 Volt test light should blink on and off the whole time the engine is being cranked.
NOTE: Don't worry about what the 12 Volt test light does before or after your helper starts cranking the engine. The only results you're interested in interpreting are the results obtained with the engine cranking.
Let's examine your test result:
CASE 1: The 12 Volt test light flashed ON and OFF. This is the correct test result.
You can conclude that your 5.2L V8 Dodge Dakota's ignition coil is bad only if you have:
- Confirmed the lack of spark at all eight spark plug wires (TEST 1).
- Confirmed that ignition coil's high tension wire does not spark (TEST 3).
- Confirmed that the ignition coil's tower does not spark (TEST 4).
- Confirmed that the ignition coil is getting 10 to 12 Volts (TEST 5).
- Confirmed that the ignition coil is getting an activation signal (TEST 6).
Here's why: If the ignition coil is getting 10 to 12 Volts (TEST 5) and it's getting an activation signal (TEST 6) then it has to spark. Since your test result confirms that it does not spark, you can conclude that the ignition coil is defective.
To solve the no-start problem on your 5.2L V8 Dodge Dakota, replace the ignition coil.
CASE 2: The 12 Volt test light DID NOT flash ON and OFF. This tells you that the ignition coil is not getting an activation signal and without it the ignition coil will not spark.
Re-check all of your connections and repeat the test. If the 12 Volt test light does not flash on and off then the most likely cause of this missing signal is a bad distributor pickup coil.
The following tutorial will help you test the distributor pickup coil on the 1990-1991 5.2L V8 Dodge Dakota:
Other Causes Of A Misfire
Quite a few things can cause a misfire problem that are not ignition system failure related. So if you tested the ignition system, with the help of this tutorial, and found no problems, then the following suggestions may help:
- Check the spark plugs.
- Check that none have broken porcelain insulators. Especially if you've recently done a tune-up and dropped one on the floor.
- You power washed the engine (this is something that you should probably avoid doing in any electronic fuel injected vehicle).
- Check for carbon tracks on the spark plugs.
- Check to see if carbon tracks have formed on the spark plug's porcelain insulator. The photo above shows what a carbon track looks like on the inside of the spark plug wire boot and on the ceramic insulator of the spark plug.
- Check engine compression.
- One of the most overlooked diagnostic tests to find the root cause of misfire is the compression test.
- You can find the engine compression test explained here: How To Test Engine Compression (Chrysler 3.9L, 5.2L, 5.9L) (at: troubleshootmyvehicle.com).
Where To Buy The Ignition Coil And Save
The ignition coil for the 1990-1991 5.2L V8 Dodge Dakota is not an expensive part. The following links will help you to comparison shop and hopefully save you a few bucks on its purchase:
NOTE: The ignition coil fits the following vehicles: 1990 and 1991 5.2L V8 Dodge Dakota.
Where To Buy The Distributor Cap, Distributor Rotor, Spark Plug Wires And Save
The following links will help you to comparison shop and hopefully save you a few bucks on its purchase:
NOTE: The distributor cap, the distributor rotor, and the spark plug wires fit the following vehicles: 1990-1991 5.2L V8 Dodge Dakota.
More 5.2L Dodge Dakota Tutorials
You can find a complete list of 5.2L Dodge Dakota tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The TPS Sensor (1990-1991 5.2L V8 Dodge Dakota).
- How To Test The MAP Sensor (1990-1991 5.2L V8 Dodge Dakota).
- How To Test The Crankshaft Position Sensor (1997-1999 V8 Dakota, Durango).
- How To Test The Throttle Position Sensor (1997-1999 V8 Dakota, Durango).
If this info really saved the day, buy me a beer!