This tutorial will help you test the distributor pickup coil in the 1990 and 1991 5.2L V8 Dodge Dakota.
The pickup coil is the defacto crankshaft position sensor of this ignition system. When it fails, your 5.2L V8 Dodge Dakota is not gonna' start.
You'll be able to diagnose it as good or bad in three tests. And these tests are done with a multimeter.
Contents of this tutorial:
- Symptoms Of A Bad Distributor Pickup Coil.
- Circuit Descriptions Of The Distributor Pickup Coil.
- TEST 1: Testing The Pickup Coil's Signal.
- TEST 2: Making Sure The Pickup Coil Has Power.
- TEST 3: Making Sure The Pickup Coil Has Ground.
- Where To Buy The Distributor Pickup Coil.
- More 5.2L Dodge Dakota Tutorials.
You can find this tutorial in Spanish here: Cómo Probar La Bobina Captadora Del Distribuidor (1990-1991 5.2L V8 Dodge Dakota) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles: 5.2L V8 Dodge Dakota: 1990, 1991.
Symptoms Of A Bad Distributor Pickup Coil
The distributor pickup coil is the 'beating heart' of your 5.2L V8 Dodge Dakota's ignition system. When it fails, the engine is not gonna' start.
And it's not gonna' start due to a lack of spark and fuel injection. This is due to the fact that the fuel injection computer uses the distributor pickup coil as a crankshaft and camshaft position sensor.
In most cases, when the distributor pickup coil fails, you're gonna' see the following trouble code stored in the computer's memory:
- Code 11: No Distributor Reference Signal Detected.
Circuit Descriptions Of The Distributor Pickup Coil
The distributor pickup coil has 3 wires coming out of its electrical connector. One wire supplies power. One wire supplies Ground. And the other wire carries the pickup coil's signal to the fuel injection computer.
In the table below you'll find a short description of each of the 3 wires:
|1990-1991 Distributor Pickup Coil Connector|
|1||Orange (ORG)||Power (9 Volts DC)|
|2||Black with light blue stripe (BLK/LT BLU)||Sensor Ground|
|3||Gray with black stripe (GRY/BLK)||Pickup Coil Signal|
The pickup coil is a Hall-Effect sensor. As such it gets power (in the form of 9 Volts) and Ground from your Dodge Dakota's fuel injection computer.
In a nutshell, when the engine starts to rotate, the pickup coil starts to create an ON/OFF voltage signal. ON is when the voltage signal is at 5 Volts DC. OFF is when the voltage signal is 0 Volts DC.
The cool thing is that we can easily 'see' this ON/OFF voltage signal by connecting a multimeter to the pickup coil's signal wire.
When a pickup coil fails, it'll usually stay stuck producing 5 Volts DC. To be a bit more specific: It'll will not create an ON/OFF (5 Volts/0 Volts) signal as the engine turns.
TEST 1: Testing The Pickup Coil's Signal
OK, to get started with the distributor pickup coil's diagnostic, we're gonna' start off by checking to see if it's creating the ON/OFF voltage signal.
We're gonna' connect a multimeter to the gray with black stripe (GRY/BLK) wire of the distributor's electrical connector.
The key to successfully testing the distributor pickup coil is to turn the engine manually. In other words: Don't use the starter motor to crank the engine.
Use a 1/2 ratchet wrench and the appropriate socket on the crankshaft pulley to turn the engine by hand. Otherwise you're not gonna' see the ON/OFF voltage signal.
IMPORTANT: The distributor pickup coil must be connected to its engine harness connector for this test to work. You'll need to connect your multimeter test lead to a back probe or a wire piercing probe to read the pickup coil's signal. You can see an example of a wire piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01).
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing.
These are the test steps:
Place your multimeter in Volts DC mode.
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
NOTE: Don't remove the distributor cap from the distributor.
With the red multimeter test lead, probe the grey with black stripe (GRY/BLK) wire of the connector.
NOTE: The distributor pickup coil must remain connected to its engine wiring harness connector to be able to read its signal.
Connect the black multimeter test lead directly on the battery negative (-) terminal.
Turn the engine hand using a 1/2 wrench and socket on the crankshaft pulley once the multimeter test lead connections are set up.
Your multimeter should see the voltage switch between 5 Volts and 0 Volts DC as the engine is turning.
Let's analyze your test result:
CASE 1: The multimeter read the indicated ON/OFF DC voltage. This is the correct test result and it tells you that the distributor pickup coil is functioning correctly (yup, not defective).
Since the distributor pickup coil IS NOT defective, something else is causing your 5.2L V8 Dakota to not start.
CASE 2: The multimeter DID NOT read the indicated ON/OFF DC voltage. This test result usually means that the distributor pickup coil is defective.
Before you replace it, make sure it's getting power and Ground. For the next test go to: TEST 2: Making Sure The Pickup Coil Has Power.