How Can I Test The Misfire?
One of the things that I've always loved about Hondas is the fact that they are pretty easy cars to work on and diagnosing a misfire on them is no different.
In this section, I'll show you a specific diagnostic strategy that'll help you find the component that's causing the problem.
STEP 1: Identify the dead cylinder. This is the most important first test that will save you a lot of time and frustration down the road by narrowing down and focusing your misfire diagnostic.
Since the Civics covered by this tutorial are OBD II equipped, identifying the dead (misfiring) cylinder usually means connecting a scan tool and checking for misfire codes (P0301, P0302, P0303, or P0304). Then by matching the misfire code to its engine cylinder using an illustration of the engine cylinders.
Unfortunately, your Civic's PCM won't always set a misfire code, even though the engine is suffering a bona-fide misfire. When this happens, there's no need to panic because there's a solution to this. The solution is to do a manual cylinder balance test.
You can find a step-by-step tutorial on how to do a manual cylinder balance test here:
STEP 2: Test the ignition system. Once you know which of the four cylinders of your Honda Civic's engine is the one that's dead then the next step is to make sure that cylinder is getting spark.
This is what I recommend:
- Check that the ignition coil (that belongs to the dead cylinder) is sparking with a spark tester.
- Testing for spark with a spark tester is the most important first test since you'll know right away if the misfire is due to a lack of spark.
- Check to see if the spark plug boots and spark plugs are swimming in engine oil from a leaking valve cover gasket (this is a very common problem with all Hondas!).
- If you got spark from your spark tester (from the cylinder the misfire code is accusing of misfiring), the next step is to remove the spark plug or spark plugs (of the affected cylinders) and check them for wear and tear, carbon tracks, anti-freeze, etc.
- If you get no spark, then the next step is to check for spark directly on the ignition coil pack tower.
- You can find all of these ignition system tests here:
STEP 3: Test the fuel injectors. If everything checks out with the ignition system then your next step is to eliminate the fuel injectors as the cause of the misfire.
This is what I recommend you do:
- Resistance test each of the 4 fuel injectors.
- Do a noid light test of each one to make sure the PCM is pulsing them (activating them).
- You can find the fuel injector tests here:
STEP 4: Test the compression of each engine cylinder. Other tests that should be done, if the ignition system and fuel injectors check out OK are:
- Engine compression test.
- Checking for vacuum leaks.
- You can find the engine compression test here:
The above list of steps may seem/sound like troubleshooting a misfire is a complicated thing but it really isn't. Depending on your level of ‘wrenching’ experience, this is something that you can accomplish without taking it to the shop.
What Tools Do I Need To Test The Misfire Code(s)?
Finding the exact cause of the misfire codes or misfire condition is possible with the proper tools. Without them, you won't be able to diagnose/troubleshoot those issues on your Honda Civic.
Depending on what the root cause of the misfire is, you may need several tools. Most of these you can buy online, none of these will break the bank and I'll make some recommendations on them. Here's a guide to some of the basic tools that can be and are used:
- Ignition System Tests:
- Spark Tester.
- Test Light.
- Fuel System Tests:
- Noid Light.
- Fuel Pressure Gauge.
- Engine Mechanical Tests:
- Compression tester.
Now of course, you'll also need basic hand tools like: screw-drivers, ratchet wrenches, sockets, etc. You'll also need a generic scan tool to retrieve the diagnostic trouble codes (DTC's) from the computer's memory.
Keep in mind that using the right tool for the job will save you time, frustration, and /or keep you from damaging the component that you're testing.
More 1.7L Honda Civic Tutorials
You can find a complete list of 1.7L Honda Civic troubleshooting tutorials here: Honda 1.7L Index Of Articles.
Here's a sample of the tutorials you'll find in the index:
- How To Test The Fuel Injectors (2001-2005 1.7L Honda Civic).
- Under-Dash Fuse/Relay Box (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 Honda 1.7L).
- How To Test Trouble Code P0135 (2001-2003 Honda 1.7L).
If this info saved the day, buy me a beer!