What Tests Can I Perform To Find The Cause Of The Misfire Condition?
Even though several different things can cause a misfire condition and resulting misfire diagnostic trouble codes (DTC), you can pinpoint the exact cause of the misfire condition.
To be able to do that, you need the right diagnostic strategy. Such a strategy will provide you with logical starting point for troubleshooting a misfire condition.
This misfire diagnostic strategy starts by reading the Diagnostic Trouble Codes (DTC), stored in your Honda's PCM's memory, with your scan tool. This misfire code will identify which cylinder is the one misfiring.
STEP 1: So then, the first order of business is to identify the dead cylinder. As mentioned above, this is usually accomplished by reading the misfire codes. Then by matching the misfire code to its engine cylinder using an illustration of the engine cylinders.
The following are my recommendations as to what to start testing after identifying the ‘dead’. Although you don't have to follow the list in that particular order (steps 2 thru' 4).
STEP 2: Test the ignition system first. Since the majority of misfires are caused by a failed component in the ignition system, you should:
- Perform a spark test (using a dedicated spark tester) on the COP ignition coil of the cylinder that the misfire code is accusing of being dead.
- 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 Coil-On-Plug (COP) ignition coil boots and spark plugs are swimming in engine oil from a leaking valve cover gasket.
- 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.
- You can find the COP ignition coil tests here:
STEP 3: Test the fuel injectors. If testing the ignition system tells you that the problem is somewhere else, then the next step is to check the fuel injectors.
You'll need to:
- 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 2.4L Honda Accord or Element.
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.
- Multimeter.
- Test Light.
- Fuel System Tests:
- Noid Light.
- Fuel Pressure Gauge.
- Multimeter.
- 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.
In Conclusion
Testing a misfire or a rough idle condition on your Honda 2.4L equipped vehicle can seem hard but if you follow the above troubleshooting steps, you'll be able to avoid replacing parts that are good.
Take advantage of the other tutorials in the Honda 2.4L section, since I've written all of them from practical every day experience and tailored for the home mechanic (the typical DIY'er - Do It Yourself'er).
If this info helped please spread the word!
If this info saved the day, buy me a beer!
