How to Test a BAD Fuel Injector (1.3L Suzuki Swift)

In this tutorial I'll show you how to test for a bad fuel injector on your 1.3L equipped Suzuki Swift (or Chevy Metro).

You don't need any expensive diagnostic equipment... since all you'll need to follow this tutorial is a simple multimeter.

Here are the contents of this article at a quick glance:

  1. Symptoms of Bad Fuel Injector.
  2. Checking the Injector's Internal Resistance.
  3. How to Find the BAD or Clogged Fuel Injector.
  4. Where to Buy the Fuel Injector and Save.
  5. More 1.3L Suzuki Tutorials

Symptoms of Bad Fuel Injector

The most obvious symptom a bad fuel injector will cause on your 1.3L Swift (Metro) is a rough idle. Of course a bad fuel injector isn't limited to causing just a rough idle though!

Here are a few more symptoms you may see when the fuel injector isn't spraying fuel into its respective cylinder:

  1. Rough idle.
  2. Lack of power.
  3. Hesitation when you accelerate your 1.3L Swift (Metro) down the road.
  4. Since the 1.3L Swift (Metro) is OBD II equipped, you'll see a misfire diagnostic trouble code (DTC):
    1. P0300: Random Cylinder Misfire.
    2. P0301: Cylinder #1 Misfire.
    3. P0302: Cylinder #2 Misfire.
    4. P0303: Cylinder #3 Misfire.
    5. P0304: Cylinder #4 Misfire.

Before we jump into the testing section of this tutorial... let me tell you that fuel injectors can fail in one of several ways. Here are some of the most basic types of fuel injector failures:

  1. The fuel injector's internal winding shorts or becomes ‘open’. This causes the fuel injector to stop injecting fuel.
  2. The fuel injector becomes clogged and doesn't spray correctly or not enough fuel.
  3. It comes on and does not turn off (due to electrical issues). In other words: it does not pulse on and off but stays on all of the time spraying a tremendous amount of fuel as soon as you turn the ignition key to the ON position.

The focus of this tutorial is to see if the fuel injector's internal coil has failed (and thus causing the fuel injector to stop injecting fuel)... but testing for a clogged injector isn't that much more complicated and I'll show you how in the next page.

Checking the Injector's Internal Resistance

How to Test a BAD Fuel Injector (1.3L Suzuki Swift)

At the heart of every fuel injector, on your 1.3L Swift (Metro), is a coil winding. In a nutshell: this coil, when energized with 12 volts and ground, opens the fuel injector's pintle. Once open the fuel starts to spray out.

When ground is removed from the injector's coil winding... the pintle closes and fuel stops coming out. Eventually the coil winding will simply short out. When this happens, its resistance will change.

You and I can measure every fuel injector's coil's resistance with a multimeter (in Ohms mode) and find out if it's within specification (or not). This is exactly what we'll do to find out if the fuel injector is fried (or not).

NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying a Digital Multimeter for Automotive Diagnostic Testing.

Alright, here are the steps:

  1. 1

    Disconnect the fuel injectors from their harness connectors.

    NOTE: To identify which cylinder the fuel injector belongs to, see the above illustration.

  2. 2

    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 in the image viewer).

  3. 3

    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.

  4. 4

    Repeat steps 1 through 3 on the remaining fuel injectors.

    NOTE: The Suzuki 1.3L Swift fuel injector factory manual resistance specification is approximately: 12 to 13 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.