How To Test The Fuel Injectors (2001-2005 1.7L Honda Civic)

How To Find The Bad Or Clogged Fuel Injector

Finding the bad or clogged fuel injector on your 1.7L Honda Civic may seem hard but it isn't.

In this section, I'll share with you a simple diagnostic strategy I've use for many years to find the fuel injector that's either clogged or fried (internally).

This are the fuel injector diagnostic test steps:

1. Find the ‘dead’ cylinder first.
   • This can easily be done by checking for misfire trouble codes with a scan tool (or code reader).
   • You won't always have a specific bad fuel injector code, but you'll definitely have a misfire code.
   • If no codes are present, then the next best thing to do is a cylinder balance test.
   • A cylinder balance test is one of the most effective ways to find a dead cylinder. The following tutorial will help you do a cylinder balance test:
     • How To Do A Cylinder Balance Test (2001-2005 1.7L Honda).
2. Check the ignition system for spark.
   • After finding the ‘dead’ cylinder, it's important to make sure that each ignition coil is sparking (delivering spark to the spark plug).
   • The following tutorial will help you test the ignition coils:
     • How To Test The Ignition Coils (2001-2005 1.7L Honda).
   • It's important that you check that the spark plug boot and spark plug are NOT soaked (or swimming) in engine oil.
   • 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.
   • After making sure that the ignition coils and spark plugs are OK, you need to check for low engine compression.
   • 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 The Engine Compression (1.7L 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 (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. Swap the fuel injector with its neighbor on the fuel injector rail.
   • I'll swap out that fuel injector with its neighbor if:
     • I have confirmed the ignition system is not at fault.
     • I have confirmed the cylinder's compression value is good (compared to the rest of the cylinders).
     • I have confirmed the fuel injector resistance is good.
     • I think the fuel injector is clogged.
     If the misfire now follows that swap, I now know that fuel injector is clogged (or bad) and needs to be cleaned or replaced.

The above testing strategy may seem like overkill or too difficult but it isn't. Most of the above tests can be done pretty fast and are not hard to do.

I can tell you from experience that the way to save yourself the frustration of replacing good parts, your vehicle doesn't need and that don't solve the problem, is testing everything. Thankfully, there's a test for just about anything on your Honda Civic!

More 1.7L Honda Civic Tutorials

You can find a complete list of Honda Civic 1.7L tutorials in this index: 1.7L Honda Civic Index Of Articles.

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

• How To Test The Alternator (2001-2005 1.7L Honda Civic).
• How To Test The Ignition Coils (2001-2005 1.7L Honda).
• How To Do A Cylinder Balance Test (2001-2005 1.7L Honda).
• How To Test The TP Sensor (2001-2005 1.7L Honda Civic).
• How To Test Trouble Code P0141 (2001-2005 Honda 1.7L).
• How To Test Trouble Code P0135 (2001-2003 Honda 1.7L).