Testing the internal coil winding of the fuel injectors on your 1.5L Toyota Tercel can be done with a multimeter. So, if the fuel injector is fried and has stopped injecting fuel, this resistance test will help you pin-point the problem.
In this tutorial I'll show you how to do this fuel injector resistance test and I'll also explain a simple diagnostic strategy to help you pin-point the problem causing a 'dead' cylinder.
Contents of this tutorial at a quick glance:
- Symptoms Of A Bad Fuel Injector.
- Checking The Injector's Internal Resistance.
- How To Find The Bad Or Clogged Fuel Injector.
- Fuel Injector Wiring Diagram.
Symptoms Of A Bad Fuel Injector
You'll see one of several of the following symptoms when on or more fuel injectors are causing a problem:
- Rough idle.
- Misfire when accelerating the vehicle down the road.
- One or more of the following trouble codes:
- P0300 Random Misfire.
- P0301 Cylinder #1 Misfire.
- P0302 Cylinder #2 Misfire.
- P0303 Cylinder #3 Misfire.
- P0304 Cylinder #4 Misfire.
When a fuel injector stops injecting fuel, it'll cause its cylinder to go 'dead'.
Checking The Injector's Internal Resistance
We're gonna' test the internal resistance of the fuel injector with a multimeter in Ohms mode.
These are the test steps:
Disconnect the fuel injectors from their harness connectors.
Set your multimeter to Ohms (Ω) mode and:
Measure the resistance of the fuel injector across its two male spade terminals with the multimeter test leads (see the illustration above).
Write down the resistance value that your multimeter records for the specific fuel injector you're testing. The illustration above will help you identify the cylinder # the fuel injector belongs to.
Repeat steps 1 through 3 on the remaining fuel injectors.
NOTE: The 1.5L Toyota resistance specification is: 13.4 to 14.2 Ohms.
Let's find out what your specific multimeter test results mean:
CASE 1: The fuel injector resistance of all 4 was within specification (or similar). This confirms that the fuel injectors are OK. Specifically, that none are shorted or open internally.
Here's why: If any one of the fuel injectors were shorted or open internally, the fuel injector would have registered a radically different resistance value on your multimeter. Since the resistance values for a 4 were uniform... this test result tells you that they are not defective.
CASE 2: One of the fuel injectors registered a completely different resistance value. This indicates that the fuel injector is BAD. Replace the fuel injector.