How To Test Engine Compression (1992-1997 2.2L Accord, Odyssey, Prelude)

In this tutorial, I'm going to explain how to test the engine compression on the Honda 2.2L 4 cylinder engine.

I'm also going to explain how to interpret your test results to find out if an engine compression problem is causing your Honda to not start or if it's causing the engine to misfire.

All the test steps are explained in detail.

You can find this tutorial in Spanish here: Cómo Probar La Compresión Del Motor (1992-1997 2.2L Accord, Odyssey, Prelude) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 2.2L Honda Accord: 1992, 1993, 1994, 1995, 1996, 1997.
• 2.2L Honda Odyssey: 1995, 1996, 1997.
• 2.2L Honda Prelude: 1992, 1993, 1994, 1995, 1996, 1997.

Symptoms Of Low Or No Engine Compression

For the most part, engine compression problems will cause one of two types of problems.

Either the engine will not start or the engine will start but it will run with a misfire.

The most common issue that you'll see with engine compression problems is that the engine will run with a misfire.

If your Honda is OBD II equipped and the engine compression problem is causing a misfire, then you're going to see the check engine light lit up by one or more of the following trouble codes:

• P0300 Random Cylinder Misfire.
• P0301 Cylinder #1 Misfire.
• P0302 Cylinder #2 Misfire.
• P0303 Cylinder #3 Misfire.
• P0304 Cylinder #4 Misfire.

Generally, when an engine compression problem causes a rough idle, you're only going to feel the problem when you come to a stop light. But as soon as you accelerate the engine, the engine feels fine.

You're also gonna' see:

• Bad gas mileage. This is caused by the simple fact that the engine is now running on less than all 4 cylinders.
• Engine pollutes more. This is also caused by the simple fact that the engine is now running on less than its full complement of cylinders. The live cylinders have to compensate for the 'dead' ones.

If your 2.2L Honda Accord (Odyssey or Prelude) is NOT OBD II equipped, you won't have any codes lighting up the check engine light, but you'll definitely feel a rough idle condition.

OK, having covered the most common scenarios of low compression and no compression, let's get testing to see if this is the case on your 2.2L Honda Accord (Odyssey or Prelude).

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:

TEST 1: Dry Engine Compression Test

The thing that makes testing the compression on the 2.2L 4-cylinder Honda engine is the fact that the spark plugs are very accessible, which makes removing them a piece of cake.

You're going to need and engine compression tester to check the engine's compression.

If you don't have one, you can run down to your local auto parts store and either borrow or buy one from them.

If you'd like to save a few bucks on the purchase of a good quality engine compression tester, take a look at my recommendations here: Which Compression Tester Should I Buy?

NOTE: It's important that you test the compression of all four cylinders.

IMPORTANT: You'll be working around a cranking engine, so you have to be careful and stay alert at all times. Think safety all of the time!

These are the test steps:

1. 1

   Disconnect the distributor from its electrical connectors. This will prevent the ignition coil from firing off spark to the spark plug wires during the test.
   
   NOTE: Disconnecting the distributor's electrical connectors is important, since it'll prevent damage to the ignition coil.

2. 3

   Remove all 4 spark plugs.
   
   As you're taking them out, be careful and don't drop any of them on the floor, or you could cause the spark plug's ceramic insulator to break, and this will cause a misfire!

3. 4

   Thread the engine compression gauge into the spark plug hole for the number 1 engine cylinder.
   
   NOTE: Hand tighten the compression gauge only! Do not use any type of tool to get it tight.

4. 5

   When everything is set up, have your helper to crank the engine. Your job is to keep your eye on the compression tester's gauge.

5. 6

   Once the needle on the gauge stops climbing, have your helper stop cranking the engine.

6. 7

   Write down the compression value on a piece of paper. Include the number of the cylinder this reading belongs to.

7. 8

   Repeat steps 4-7 on the other 3 cylinders.

Let's take a look at what your test results mean:

CASE 1: No compression in 2 or more cylinders. This test result tells you that the engine has serious internal problems.

The most common issues would be: Broken timing chain. Or a blown head gasket. Or the engine threw a rod.

CASE 2: Low compression in one or more cylinders. To a certain point, it's normal for the compression to vary a little between cylinders (as the engine accumulates thousands of miles).

But if these values vary too much, then you're gonna' have a bonafide misfire on your hands.

The next step is to do some math to find out if this low compression value is within a normal parameter or not. Go to: Interpreting Your Compression Test Results.

Interpreting Your Compression Test Results

If you're reading this section, more than likely the engine compression results you got from TEST 1 indicate that one or more cylinders have a lower compression value than the others.

Depending on the value of that low engine compression result you got, you may have nothing to worry about or it could be the source of the misfire that you're trying to troubleshoot.

It's not unusual for the cylinders to wear out unevenly, especially on high-mileage engines or engines that didn't get a lot of maintenance.

So in this section, I'm going to explain how you can find out if that low engine compression value is causing a problem or not.

OK, you can do this one of two ways: You can calculate this 15% difference with pen and paper or you can use my low compression calculator. You can find the low compression calculator here: Online Low Engine Compression Calculator.

If you want to manually calculate the 15% difference, here's what you'll need to do:

• STEP 1: Multiply the highest compression value by 0.15 (this is the decimal value of 15%).
• STEP 2: Round the result to the nearest one (for example: 25.6 would become 26).
• STEP 3: Subtract the result (the number that was rounded) from the highest compression value.
• ANSWER: The result of this subtraction is the lowest possible compression value any cylinder can have.

Now, let me give you a more specific example: Let's say that a 2.2L Honda Accord I'm working on produced the following compression readings:

Cylinder	Pressure
#1	165 PSI
#2	95 PSI
#3	155 PSI
#4	175 PSI

My next step is to do the following calculation:

• STEP 1:  175 x 0.15 = 26.25.
• STEP 2:  26.25 = 26 (rounded to nearest one).
• STEP 3:  175 - 26 = 149.
• ANSWER:  149 PSI. Any cylinder with this compression (or lower) value will misfire.

Since cylinder #2 is only producing 95 PSI, I can now conclude that it's 'dead' and causing a misfire.

To find out if the lowest compression value you got from your engine compression test is within a good range, you'll need to do the same calculation. Of course, you'll need to use the highest compression value you got and not the one in the example.

Once you'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 Engine Compression Test.

TEST 2: Wet Engine Compression Test

If you do have one or more cylinders with low or no engine compression, the next step is to find out what is causing that compression value.

Usually, one of two things will cause that low or no compression value you got in TEST 1.

Either the piston rings are severely worn/damaged or the cylinder head valves are worn/damaged in the dead cylinder.

We can easily find out without having to disassemble the engine with a wet engine compression test.

The wet engine compression test simply involves adding about 1-2 tablespoons of engine oil to the dead cylinder and then retesting it's compression.

If the compression value increases, then you can conclude that the piston rings, of the dead cylinder, are the ones behind its low compression value.

If the value does not increase, then you can correctly conclude that the low or no compression value is due to that cylinder having worn/damaged cylinder head valves.

OK, let's start:

1. 1

   Add a small amount of engine oil to the cylinder that reported low compression or no compression in the 'Dry' compression test.
   
   The amount should be about 1 to 2 tablespoons of oil.

2. 2

   Install the compression tester onto the cylinder.
   
   Do not use any type of tool to tightened the compression tester. Hand tight is fine.

3. 3

   When all is set up, have your helper crank the engine while you observe the gauge.

4. 4

   Once the needle on the gauge stops climbing, have your helper stop cranking the engine.

5. 5

   You'll get one of two results:
   
   1.) The compression value will go up (from the one you recorded before).
   
   2.) The compression value will stay the same.

6. 6

   Repeat steps 1-4 on any other cylinder with a low compression test result.

Let's examine your test results:

CASE 1: The compression value shot up. This tells you that that cylinder's piston compression rings are worn out and are behind the low compression test result you got in TEST 1.

CASE 2: The compression value stayed the same. This confirms that that cylinder's valves are behind the low to 0 PSI compression result you obtained in TEST 1.

More 2.2L Honda Accord, Odyssey And Prelude Tutorials

You can find a complete list of 2.2L Honda Accord and Odyssey tutorials in this index:

• Honda 2.2L Index Of Articles.

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

• How To Test The MAP Sensor (1994-1997 2.2L Accord, Odyssey, Prelude).
• How To Test The Head Gasket (1992-1997 2.2L Accord, Odyssey, Prelude).
• P0420 -What Does It Mean? (1995-1997 2.2L Honda Accord And Odyssey).
• How Often Should I Replace The Spark Plugs? (2.2L Honda Accord).