How To Test a Mazda 626 Fuel Injector

How To Test a Mazda 626 Fuel Injector


When your Mazda 626 is idling rough or has a misfire condition, this may be a sign of injector failure. Your 626 Fuel Injector may be clogged or have failed completely. When this occurs it’s going to create a “dead” cylinder as the injector isn’t working correctly. Today I’ll be showing you how to test your 626 Fuel Injector using a digital multimeter.

Our test vehicle today is a 1999 Mazda 626 or MX6 with a 2.0 liter engine in it. The 2.0 liter 4 cylinder version of this engine is far easier to work on and reach the injectors, compared to the V6 models. Because the Mazda 626 Fuel Injector is easy to get to, testing this in your 626 is easy to do.

How To Test a Mazda 626 Fuel Injector 2

Symptoms of a failed 626 Fuel Injector

When your Mazda fuel injector has an issue, it’s going to create quite a few problems with your 626. The most obvious issue is a misfire, or a OBDII trouble code for Mazda misfire in your 2.0 liter engine. Here are some other issues that can arise from a bad fuel injector.

  • Poor idle
  • Hesitation
  • Bad acceleration
  • Misfire

When you have any of these symptoms, you can use a digital multimeter to see if your 626 Fuel Injector is still good. We’ll be starting our tutorial by showing you how to measure the internal resistance of your 626 Fuel Injector.

Testing your Mazda 626 Fuel Injector

There’s a few different ways that your Mazda injector can fail on you. One is that the injector can become clogged from poor fuel or lack of fuel filter efficiency. The other is that the internals of your 626 fuel injector have failed.

1999 Mazda 626 fuel injector

Using your digital multimeter you will need to unplug your fuel injectors to test the internal resistance. Once you have the 626 Fuel Injector unplugged, you will be measuring by placing both of your multimeter leads to either of the injector pins.

Again although our test car is a 1999 Mazda 626, this test can be done for any 1993-1999 626 as well as the MX6 with a 2.0L engine. Turn your digital multimeter to Ohms mode, and once you have both leads on the pins you can read the internal resistance.

The internal resistance for your 626 Fuel Injector should be between 12 to 16 Ohms (Ω). If your injectors don’t respond with this resistance value, it’s time to replace your fuel injector to fix your 626. Shop our online store for a replacement fuel injector or head over to your local auto parts store to shop for a new injector. Replace your Mazda 626 injector to restore your idle and engine operation.

Have any questions about our 626 Fuel Injector How To DIY tutorial? Leave us a message below and let us know!