How To Test The Fuel Injectors (1992-1995 1.5L Honda Civic)

How To Find The Bad Or Clogged Fuel Injector

Finding the exact cause behind your 1.5L Honda Civic's misfire (rough idle) isn't hard. But, if you're not sure if a bad or clogged fuel injector is behind the problem, the following testing suggestions will help you.

The troubleshooting strategy below, has helped to accurately diagnose a failed/clogged fuel injector about 95% of the time and this has meant saving time, frustration, and more importantly: money.

You can find even more info in the following article: How To Test A Misfire Condition (1.5L Honda Civic).

OK, below are the diagnostic steps I take when trying to diagnose a bad fuel injector:

1. Find the ‘dead’ cylinder first.
   • This is the most important first step. It involves doing a cylinder balance test first. If you've never done a cylinder balance test before, you it explained here: How To Do A Cylinder Balance Test (1992-1995 1.5L Honda Civic)
2. Check that all spark plug wires are delivering spark.
   1. It's important to make sure that each cylinder is getting spark with a dedicated spark tester.
      • You can find a step-by-step guide here: How To Test The Igniter, Ignition Coil Accord, Civic, CRV, and Odyssey (at: easyautodiagnostics.com).
   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. Check engine compression.
   1. After making sure that all 4 spark plug wires are 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 Test Engine Compression (1.5L Honda Civic).
4. Noid light test.
   • If every test above checks out OK, then the next step is to do a fuel injector Noid light test.
   • The Noid light test will help you 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 (at: easyautodiagnostics.com).
5. Swap the fuel injector with its neighbor on the fuel injector rail.
   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...
      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, I now know that fuel injector is clogged (or bad) and needs to be cleaned or replaced.

Finding the bad/clogged fuel injector can be a challenge on your 1.5L Honda Civic but it's doable. What will help you save a lot of time, money and frustration is to first find the ‘dead’ cylinder. Following the above diagnostic strategy has saved my lunch quite a few times and I think it'll help you too!

More 1.5L Honda Civic Tutorials

You can find a complete list of 1.5L Honda Civic tutorials in this index:

• Honda 1.5L Index of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The MAP Sensor (1.5L Honda Civic).
• How To Test The Throttle Position Sensor (1992-1995 1.5L Honda Civic).
• How To Test Engine Compression (Honda 1.5L).
• How To Test The Fuel Pump In 2 Tests (1.5L Honda Civic).
• How To Test The Igniter, Ignition Coil Accord, Civic, CRV, and Odyssey (at easyautodiagnostics.com).