How To Test The Fuel Injectors (2002-2005 GM 2.2L Ecotec)

How To Find The Bad Or Clogged Fuel Injector

A lot of folks find troubleshooting a bad fuel injector intimidating on the 2002-2005 2.2L Ecotec engines. I can tell you from personal experience that if you have a specific diagnostic test strategy, then finding the bad fuel injector (or exonerating them) becomes easy.

In this section I'll present to you my fuel injector diagnostic strategy. The following set of tests have always helped to nail down the exact cause of the misfire (whether caused by a bad fuel injector or not). I'm confident that they'll help you too:

1. Find the ‘dead’ cylinder first.
   • This is the most important first step. You can do this by connecting a scan tool (or code reader) and identifying the specific misfire code that's registered in your car's PCM's memory.
2. After identifying the ‘dead’ cylinder, make sure it's getting spark.
   1. It's important that you check the tower (of the ignition coil pack assembly) for spark with a dedicated spark tester.
   2. It's important that you check that the spark plug boot and spark plug are NOT soaked (or swimming) in engine oil.
   3. You should also remove the spark plugs and check them for cracks or carbon tracks (this is SO important).
      • Here's a real life case study on carbon tracks and how they can cause a Misfire: Carbon Tracks Are A Common Cause Of Ignition Misfires (at: easyautodiagnostics.com).
3. If the ‘dead’ cylinder has spark, the next step is to make sure it has good compression.
   1. After making sure that the ‘dead’ cylinder's plug wire is delivering spark, you need to check for low engine compression.
   2. This is one of the most overlooked tests when diagnosing a misfire or rough idle condition. You can find the test here:
      • How To Do An Engine Compression Test (GM 2.0L, 2.2L, 2.5L).
4. If the ‘dead’ cylinder has spark and good compression, the next step is a fuel injector Noid light test.
   • If every test above checks out OK, then the next step is to make sure that the fuel injector is being activated.
   • The following Noid light article/tutorial may help you: How To Use A Noid Light And Where To Buy It (I know that this is not the most in-depth article on the subject, but it should give you an idea of what is involved).
5. If the ‘dead’ cylinder has spark, good compression, and is being activated; the next step is swap the fuel injector.
   1. If I've found out that I have a specific ‘dead’ cylinder and:
      1. The ignition system is not at fault.
      2. That cylinder's compression value is good (compared to the rest of the cylinders).
      3. The fuel injector resistance is good and is being activated by the fuel injection computer and
      4. I think the fuel injector is clogged, I then swap out that fuel injector with its neighbor.
      If the misfire now follows that swap then I now know that fuel injector is clogged (or bad) and needs to be cleaned or replaced.

As you can see, finding the cause of the misfire boils down to a process of elimination. As you start off by identifying the ‘dead’ cylinder, the next steps are too make sure that its getting spark, good compression, etcetera.

Where To Buy The Fuel Injector And Save

In need of a new fuel injector? Check out the following links and comparison shop the fuel injector on your 2.2L Ecotec equipped GM vehicle:

Not sure if the above fuel injectors fit your particular 2.2L Ecotec equipped GM vehicle? Don't worry, once you arrive on the site, they'll make sure it fits! If it doesn't, they'll find you the right one.