TEST 3: Checking The Distributor Cap For Spark
The spark tests in TEST 1 showed that some spark plugs aren't sparking. This usually happens for one of two reasons:
- Bad spark plug wire: The wire is old or damaged and can't deliver spark to the spark plug anymore.
- Bad distributor cap: The metal terminal inside the distributor cap tower is covered in carbon tracks or corrosion, stopping it from sending spark to the spark plug wire.
To figure out what's causing the issue, we'll run a quick spark test on the distributor cap tower(s) connected to the non-sparking spark plug wire(s). If more than one wire isn't sparking, we'll test them one by one.
Here's what we're looking for:
- If the distributor cap tower sparks: The spark plug wire is bad.
- If there's no spark: The distributor cap tower itself is bad.
Alright, let's get started:
- 1
Make sure all spark plug wires are connected to their spark plugs (if any were unplugged).
- 2
Unplug the spark plug wire that didn't spark from its distributor cap tower.
NOTE: If multiple wires aren't sparking, test them one at a time. For now, disconnect just one. In Step 8, we'll move on to the next. - 3
Insert the spark tester into the distributor cap tower.
- 4
Use a battery jump-start cable to Ground the spark tester to the battery's negative (-) terminal.
NOTE: The jump-start cable also helps keep the spark tester in place inside the distributor tower. - 5
Have someone crank the engine.
CAUTION: The engine might start during this test. Stay alert and take all safety precautions. - 6
You'll see one of two results: Spark or no spark.
- 7
Remove the spark tester and reconnect the spark plug wire.
- 8
Repeat the test for any other distributor cap towers connected to non-sparking spark plug wires from TEST 1.
Now, let's break down what your test result means:
CASE 1: The spark tester sparked inside the distributor cap tower. That's exactly what we want to see.
This confirms the distributor cap tower is working fine, and the non-sparking spark plug wire is bad. Replace all spark plug wires as a set.
CASE 2: The spark tester DID NOT spark inside the distributor cap tower. That means the distributor cap is bad.
Replace both the distributor cap and rotor, then rerun TEST 1 to check the non-sparking spark plug wires again.
TEST 4: Making Sure The Ignition Coil Is Getting Power
By now, you've confirmed that:
- None of the four spark plug wires sparked (TEST 1).
- The ignition coil doesn't spark (TEST 2).
Now, let's see if the ignition coil's getting 10-12 Volts DC when you turn the key to ON.
To check that, we're gonna test the voltage right at the ignition coil's (+) terminal (see the image above).
Alright, here's what you gotta do:
- 1
Turn the key to ON, but don't start the engine.
- 2
Take off the distributor cap if it isn't already off.
- 3
Set your multimeter to Volts DC mode.
- 4
Hook up the black multimeter lead to the battery's negative (-) terminal.
- 5
Touch the red multimeter lead to the ignition coil's (+) terminal.
- 6
The multimeter should read between 10 and 12 Volts DC.
Now, let's figure out what your test result means:
CASE 1: The multimeter reads 10 to 12 Volts DC. That's exactly what we want to see.
Next, we gotta check if the ignition coil's getting its activation signal. Head over to: TEST 5: Making Sure The Ignition Coil Is Getting Its Activation Signal.
CASE 2: The multimeter DIDN'T read 10 to 12 Volts DC. That usually means the ignition switch isn't sending power to the ignition coil.
Troubleshooting this lack of voltage isn't covered in this guide, but you'll need to track down the problem. Once the ignition coil gets power again, it should start sparking.
TEST 5: Making Sure The Ignition Coil Is Getting Its Activation Signal
Alright, your tests have confirmed so far that:
- None of the four spark plug wires are sparking (TEST 1).
- No spark's coming from the ignition coil tower (TEST 2).
- The ignition coil's getting 10 to 12 Volts (TEST 4).
Now for the last test —let's see if the igniter's sending an activation signal to the coil.
To check this, we're gonna use a 12-volt automotive test light to probe the (-) terminal on the ignition coil (see image above).
Don't have a 12-volt test light? Here's the one I recommend: Lisle 28400 Heavy Duty 12 Volt Test Light (at: amazon.com).
IMPORTANT: The igniter's gotta stay connected to its electrical connector for this test to work.
Alright, let's do this:
- 1
Clip the 12V test light's alligator clip to the battery's positive (+) terminal.
- 2
Touch the test light's metal probe to the ignition coil terminal marked (-).
NOTE: Keep the probe on the terminal while doing the next step. - 3
Have a helper crank the engine while you watch the 12V test light.
- 4
The 12V test light should blink ON and OFF continuously as the engine cranks.
Let's figure out what your test result means:
CASE 1: The 12V test light blinked ON and OFF. That's the right result, which means the igniter's working and sending the activation signal to the ignition coil.
If you've confirmed all of these:
- None of the four spark plug wires are sparking (TEST 1).
- The ignition coil's tower isn't sparking (TEST 2).
- The ignition coil's getting 10-12 Volts (TEST 4).
- The ignition coil's receiving the activation signal (this test).
Then the ignition coil's bad and needs replacing.
CASE 2: The 12V test light DIDN'T blink ON and OFF. That means the ignition coil isn't sparking 'cause it's not getting an activation signal from the igniter.
The igniter's job is to generate and send that signal. Your next step is to test the igniter.
More 1.6L Toyota Corolla Tutorials
You can find a complete list of 1.6L Toyota Corolla tutorials and wiring diagrams in this index:
Here's a sample of the tutorials you'll find there:
- How To Test The Fuel Pump (1989-1993 1.6L Toyota Corolla).
- How To Test The Throttle Position Sensor (1989-1997 1.6L Toyota Corolla).
- How To Test Engine Compression (1989-1997 1.6L Toyota Corolla).
- How To Test A Blown Head Gasket (1989-1997 1.6L Toyota Corolla).
If this info saved the day, buy me a beer!
