TEST 3: Checking The Distributor Cap For Spark
TEST 1's spark tests showed that some spark plugs aren't firing. That usually happens for one of two reasons:
- Bad spark plug wire: If the wire's old or damaged, it won't send spark to the spark plug anymore.
- Bad distributor cap: Carbon tracks or corrosion on the metal terminal inside the distributor cap tower block the spark from reaching the spark plug wire.
To figure out what's wrong, you're gonna run a quick spark test on the distributor cap tower(s) linked to the non-sparking spark plug wire(s). If more than one wire's dead, test them one at a time.
Here's what to watch for:
- If the distributor cap tower sparks: The spark plug wire's bad.
- If there's no spark: The distributor cap tower itself is bad.
Let's jump in:
- 1
Check that all spark plug wires are plugged into their spark plugs (if any were disconnected).
- 2
Unplug the spark plug wire that didn't spark from its distributor cap tower.
NOTE: If more than one wire isn't sparking, test them one at a time. For now, remove just one. In Step 8, you'll move on to the next. - 3
Stick 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 holds 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 follow all safety precautions. - 6
You'll see one of two things: Spark or no spark.
- 7
Take out the spark tester and plug the spark plug wire back in.
- 8
Run the test again for any other distributor cap towers linked to non-sparking spark plug wires from TEST 1.
Let's break down what your test result means:
CASE 1: The spark tester sparked. That's exactly what you wanna see.
This proves the distributor cap tower's fine, but the spark plug wire isn't. Replace all spark plug wires as a new set.
CASE 2: The spark tester DIDN'T spark. That tells you the distributor cap's bad.
Replace both the distributor cap and rotor, then run TEST 1 again to check the non-sparking spark plug wires.
TEST 4: Making Sure The Ignition Coil Is Getting Power
At this point in your diagnostic, you've confirmed:
- None of the four spark plug wires sparked (TEST 1).
- The ignition coil didn't spark (TEST 2).
The next thing we need to find out is if the ignition coil's getting 10-12 Volts DC (when you turn the key to ON position).
To do that, you're gonna check 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 crank the engine.
- 2
Remove the distributor cap if it's still on.
- 3
Place your multimeter in Volts DC mode.
- 4
Clip the black multimeter lead to the battery's negative (-) terminal.
- 5
Press the red multimeter lead against the ignition coil's (+) terminal.
- 6
The multimeter should show between 10 and 12 Volts DC.
Now, let's break down what your test result means:
CASE 1: The multimeter shows 10 to 12 Volts DC. That's exactly what you wanna see.
Next, you 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 show 10 to 12 Volts DC. That usually means the ignition switch isn't sending power to the ignition coil.
This guide doesn't cover troubleshooting that issue, but you'll need to track down what's keeping power from reaching the ignition coil. Once the ignition coil gets voltage again, it should start sparking.
TEST 5: Making Sure The Ignition Coil Is Getting Its Activation Signal
Alright, so far your tests have confirmed:
- TEST 1: None of the four spark plug wires spark.
- TEST 2: The ignition coil tower isn't sparking.
- TEST 4: The ignition coil's getting 10 to 12 Volts.
Now for the final test —let's find out if the igniter's sending an activation signal to the coil.
To check, you're gonna use a 12-volt automotive test light to probe the (-) terminal on the ignition coil (check the image above).
Don't have a 12-volt test light? Here's the one I use and recommend: Lisle 28400 Heavy Duty 12 Volt Test Light (at: amazon.com).
IMPORTANT: For this test to work, the igniter's gotta stay plugged into its electrical connector.
Alright, let's get to it:
- 1
Hook the 12V test light's alligator clip to the battery's positive (+) terminal.
- 2
Press the test light's metal probe against the ignition coil terminal marked (-).
NOTE: Keep the probe on the terminal while doing the next step. - 3
Have someone crank the engine while you watch the 12V test light.
- 4
The 12V test light should blink ON and OFF over and over as the engine cranks.
Let's break down what your test result means:
CASE 1: The 12V test light blinked ON and OFF. That's exactly what should happen, which means the igniter's working and sending the activation signal to the ignition coil.
If you've confirmed all of these:
- TEST 1: None of the four spark plug wires spark.
- TEST 2: The ignition coil's tower isn't sparking.
- TEST 4: The ignition coil's getting 10-12 Volts.
- This test: The ignition coil's receiving the activation signal.
Then the ignition coil's bad and needs to be replaced.
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 move? 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!
