Testing the engine compression on the 1991-2001 2.0L equipped CR-V is pretty easy and what makes is so is the fact that removing the spark plugs is easier than on most cars and SUV's out there.
In this tutorial, I'm going to explain how to do the compression test and more importantly, how to interpret your test results to find out if the compression of each cylinder is within specification.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar La Compresión Del Motor (1997-2001 2.0L Honda CR-V) (at: autotecnico-online.com).
CYLINDER MISFIRE DIAGNOSTICS:
ENGINE NO-START DIAGNOSTICS:
Symptoms Of Low Or No Cylinder Compression
The majority of engine compression problems fall within two specific categories. The first one is low compression in one or two cylinders causing a misfire condition. The second one is zero or low compression in all cylinders causing the engine to not start.
Here are some of the symptoms you may see when your Honda CR-V has engine compression problems:
- Engine cranks but does not start (0 compression in all cylinders).
- Blue smoke coming out of the tailpipe.
- Rough idle (engine misfires).
- Misfire trouble codes (P0300, P0301, P0302, or P0304) lighting up the check engine light on your CR-V's instrument cluster.
- Bad gas mileage.
- Engine 'misses' at idle but 'miss' disappears as you accelerate the vehicle.
- Check engine light is illuminated with a MAP sensor trouble code (even tho' the MAP sensor is good).
With this info under our belts, let's head down to the next subheading and get testing.
Which Compression Tester Should I Buy?
There are lot of engine compression testers to choose from and many places to buy them. I'm gonna' make some recommendations to you:
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TEST 1: Dry Compression Test
To test the compression of your Honda CR-V engine, you're going to need to remove the spark plugs.
It's extremely important that you do not remove the spark plugs with a hot engine. So if the engine has been running for any amount of time, you need to let the engine cool down completely.
Removing the spark plugs from a hot engine can damage the spark plug threads in the spark plug holes in the cylinder head which is made of aluminum.
OK, these are the test steps:
- 1
Disable the ignition system by disconnecting the distributor from its electrical connectors. This will prevent the ignition coil from sparking during the test.
- 2
Remove the spark plugs from a slightly warmed up engine (if it starts and runs). Remember, the engine can not be hot!
When removing the spark plugs, be careful not to drop any of them on the floor, or you run the risk of having the spark plugs porcelain insulator crack and then you'll have a misfire on your hands.
If the engine does not start, don't worry about it being warmed up. - 3
Thread the engine compression gauge into the spark plug hole for the number 1 engine cylinder. Hand tighten the compression gauge only! Do not use any type of tool to get it tight.
- 4
Have your helper crank the engine till the needle on the compression gauge stops climbing.
Now, record on paper the value at which the needle stopped and the number of the engine cylinder on a piece of paper. Release the pressure on the gauge and repeat this step one more time.
Repeat this test step on the remaining 3 cylinders.
Let's take a look at what your test results mean:
CASE 1: You got 0 compression on all 4 cylinders. This test result is usually due to one of the following conditions:
- Timing belt problem.
- Blown head gasket.
- Blown engine.
Any compression value below 100 PSI (even if it doesn't go down to 0 PSI) means internal mechanical engine trouble.
CASE 2: You got uneven compression values between engine cylinders. To a certain extent, uneven compression values might be normal if the engine has a lot of miles.
The next step now is to find out if your compression test results are within normal operating parameters. For this info go to: Interpreting The Compression Test Results.
Interpreting The Compression Test Results
Okay, in this section, we're gonna' interpret your Honda CR-V's compression test results and find out if the lowest compression value is within normal parameters.
Let me start off by telling you that it's normal for the compression values to vary between each other somewhat. What isn't normal is if the values vary too much.
The rule of thumb is that the lowest compression value can not vary more than 15% of the highest value (that you wrote down in TEST 1). If any value is lower by more than 15%, then that engine cylinder is going to misfire. This misfire will cause your 2.0L Honda CR-V's engine to idle rough.
How do you figure this out? You can find out by using my online low compression calculator here: Online Low Engine Compression Calculator or by calculating this 15% difference manually.
To understand how to figure out this 15% thing manually, let's say that my 2.0L Honda CR-V produced the following compression test results:
- Cylinder #1 175 PSI.
- Cylinder #2 165 PSI.
- Cylinder #3 160 PSI.
- Cylinder #4 120 PSI.
The next step is to do the following math:
- Multiply .15 (15%) by the highest value: 175 x 0.15. This gives us 26.25, but we'll round it out to 26.
- Next, we subtract 26 from 175: 175 - 26 = 144.
- So now we know that the lowest possible compression value is: 144 PSI.
This means that cylinder #4, which has a compression value of 120 PSI, is the one causing the misfire because it's below the 144 PSI minimum.
Once we've found the 'dead' cylinder, the next step is to find out what's causing the low compression value. For this step, go to: TEST 2: Wet Compression Test.
TEST 2: Wet Compression Test
In this test section, we're now gonna' find out what is causing the low compression value that you got from the compression test (in TEST 1).
To give you some more details, what usually ends up causing a low (or zero) compression value in any given engine cylinder are worn/damaged piston rings or cylinder head valves.
Thankfully, you and I can find out which of the two it is by doing a 'wet' compression test (instead of tearing into the engine to find out). And that's what we're going to do in this section.
OK, this is what you'll need to do:
- 1
Add a tablespoon (or two) of engine oil in the cylinder you need to retest. I suggest using a small and long funnel so that the oil will reach the inside of the cylinder.
- 2
Once you've added the oil, install the compression gauge, and as before just hand tighten it.
- 3
Now, have your helper crank the engine till the needle stops climbing on the compression gauge.
- 4
You'll see one of two results:
1.) The needle will climb higher than the previous compression number you recorded for this specific cylinder.
2.) The needle will not move at all or stay at the same number you recorded earlier.
What ever value your compression tester reads, write it down again. - 5
If you have another cylinder that needs to be tested, repeat steps 1 thru' 4 on it now.
Let's take a look at what your compression test results mean:
CASE 1: The compression value shot up for the low compression cylinder. This test result lets you know that extremely worn piston rings are the ones causing the low compression value in that specific cylinder.
The reason the compression value shot up is due to the fact that the motor oil you just added helped the piston rings to create a tighter seal. This type of test result only happens when the problem is due to worn piston rings.
CASE 2: Your compression value DID NOT shoot up (stayed the same). This test result lets you know that that cylinder's cylinder head valves are worn/damaged and are the ones causing the low compression value in that specific cylinder.
More 2.0L Honda CR-V Tutorials
You can find a complete list of tutorials here: Honda 2.0L Index Of Articles.
Here's a sample of the tutorials you'll find there:
- How To Test The Ignition Coil (1999-2001 2.0L Honda CR-V).
- How To Test The Ignition Coil (1997-1998 2.0L Honda CR-V).
- How To Test The Ignition Control Module (1999-2001 2.0L Honda CR-V).
- How To Test The TPS (1997-2001 2.0L Honda CR-V).
- How To Test The MAP Sensor (1997-2001 2.0L Honda CR-V).
On YouTube, check out my following videos:
- How To Test The Ignition Coil (1999-2001 2.0L Honda CR-V) (at YouTube).
- How To Test The Ignition Control Module (1999, 2000, 2001 2.0L Honda CR-V) (at YouTube).
- How To Test The Fuel Pump (1997-2001 2.0L Honda CR-V) (at: YouTube).
If this info saved the day, buy me a beer!
