TEST 1: Testing For Spark At All 4 Cylinders
The very first thing we're gonna' do is make sure that spark is missing from all 4 cylinders. If spark is present in all four cylinders (even if your Tercel doesn't start), then you can rule out the igniter as bad.
To get an accurate result, I recommend that you use a dedicated spark tester for this test. If you can, I suggest using an HEI spark tester. You can find out more about it (and where to buy it here: HEI Spark Tester (at: easyautodiagnostics.com).
Alright, let's get started:
- 1
Connect your spark tester to spark plug wire for cylinder #1. Ground the spark tester using a battery jump start cable to the battery negative (-) post.
- 2
Have a helper crank the engine while observe the spark tester from a safe distance.
- 3
The spark tester should spark when the engine is cranking.
- 4
Repeat the above 3 steps on the remaining cylinders.
Let's take a look at what your test results mean:
CASE 1: All 4 cylinders have spark. This test result tells you that the igniter is activating the ignition coils and that it's not defective.
CASE 2: No spark on all 4 cylinders. The next step is to make sure that the igniter (and the ignition coils) are getting battery power. For this test go to: TEST 2: Making Sure The igniter Is Getting Power.
CASE 3: No spark on cylinders 1 and 4. This test result usually tells you that the ignition coil that feeds cylinders 1 and 4 is defective.
CASE 4: No spark on cylinders 2 and 3. This test result usually tells you that the ignition coil that feeds cylinders 2 and 3 is defective.
TEST 2: Making Sure The Igniter Is Getting Power
Now that you have confirmed that all 4 cylinders don't have spark, the next step is to make sure that the igniter and ignition coils are getting battery power when the ignition key is turned on.
Since the same circuit feeds the ignition coils and igniter with battery power, we need only test the black with orange stripe (BLK/ORG) of the igniter harness connector for 12 Volts DC.
The BLK/ORG wire connects to terminal #7 of the igniter's electrical connector (see illustration above).
Let's get started:
- 1
Disconnect the igniter from its 8-wire electrical connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Connect the red multimeter test lead to the BLK/ORG wire of the igniter's electrical connector.
This is the wire that connects to terminal number 7 in the illustration above (of the igniter's harness connector). - 4
Connect the black multimeter test lead to the battery negative (-) terminal.
- 5
Have your helper turn the key to the ON position.
- 6
Your multimeter should read 10 to 12 Volts DC if the igniter and ignition coils are getting battery power.
Let's take a look at what your test results mean:
CASE 1: The igniter is getting 10 to 12 Volts DC. This is the correct and expected test result. The next step is to make sure the igniter is getting Ground. For this step, go to: TEST 3: Making Sure The Igniter Is Getting Ground.
CASE 2: The igniter IS NOT getting battery power. This tells you that the igniter is not working due to a lack of battery power.
Your next step is to find out why this battery power is missing and restore it. Once battery power is restored, the igniter should function again.