STEP 1: Find The Dead Cylinder First
The very first step is to identify the ‘dead’ cylinder by checking for trouble codes with a scan tool or code reader.
Once the dead cylinder is found, then we can focus on finding out what it's missing (spark, fuel, or compression).
The way to find out which is the misfiring trouble code is by connecting a scan tool or trouble code reader to your 2.4 Honda CR-V.
Once you have the misfire trouble code you can identify which cylinder is the one the computer is accusing of misfiring.
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
Once you've extracted the specific cylinder misfire trouble code, the next step is to make sure that the dead (misfiring) cylinder is getting spark.
STEP 2: Making Sure The Dead Cylinder Is Getting Spark
Once the dead cylinder is identified, the next step is to make sure that it's getting spark.
The ignition system components that could cause the dead cylinder to misfire (if defective) are:
- A defective distributor cap.
- A defective spark plug wire.
- A broken spark plug.
- A spark plug whose air gap is not within specification.
- Ignition coil boot and spark plug swimming in engine oil.
In a nutshell, what you'll be doing is:
- Checking that the dead cylinder's spark plug wire is sparking.
- Checking that the dead cylinder's spark plug's air gap is OK.
- Making sure that the dead cylinder's spark plug wire's boot and spark plug are not swimming in engine oil.
To get the most accurate test result from your spark test, it's important that you use a dedicated spark tester.
This tutorial will help with testing the spark plug wire and the distributor cap: Distributor Cap And Spark Plug Wires Misfire Tests (2.0L Honda CR-V).
NOTE: One of the most common problems I've encountered with the Honda 2.0L engine (that cause a misfire) is the spark plug tubes filled with engine oil. This is due to the fact that the spark plug tube seals have hardened and are letting engine oil leak into the spark plug tubes. This causes the spark plug and spark plug wire boot to get soaked in engine oil. The end result of this will be a misfire condition.
If the dead cylinder is getting spark, its spark plug wire and its spark plug are OK; then the next step is to check that the dead cylinder has good compression.
STEP 3: Testing The Compression Of The Dead Cylinder
Now that you've eliminated the ignition system (as the cause of your 2.0L Honda CR-V's misfire), the next step is to make sure that the dead cylinder has good compression.
What we want to find out is if the dead cylinder's compression value is within 15% of the highest compression value of the other 3 cylinders.
In a nutshell, what you'll be doing is:
- Checking the compression of all 4 cylinders.
- Multiply the highest compression number (you got from your test) by 0.15.
- Subtract the product (of your multiplication problem) from the highest compression number.
- The difference (from your subtraction problem) is the lowest compression number (value) the dead cylinder can have. Any number (value) lower than this and the cylinder will misfire due to low compression.
To make more sense of the explanation above, let's say that I got the following compression values:
- Cyl. #1 = 175 PSI
- Cyl. #2 = 160 PSI
- Cyl. #3 = 170 PSI
- Cyl. #4 = 130 PSI.
My next step would be to multiply the highest compression number by 0.15: 175 X 0.15 = 26.25. I'll round off 26.25 to 26.
Now, I'm gonna' subtract 26 from the highest compression number: 175 - 26 = 144. This tells me that the lowest possible compression value the dead cylinder can have is 144 PSI. Anything lower and it'll misfire.
Since cylinder #4 has 130 PSI compression, I can now confidently conclude that its low compression is behind the misfire trouble code and problem making the engine misfire.
The following tutorial explains the compression test in more detail here: How To Test Engine Compression (1997-2001 2.0L Honda).
Now, if the dead cylinder's compression checks out fine, then the next step is to check the internal resistance of its fuel injector. Go to: STEP 4: Testing The Dead Cylinder's Fuel Injector.