What makes testing the compression of the 1.7L Honda Civic engine easy is the spark plugs are very accessible (since you'll need to remove them for the test).
In this tutorial, I'll explain how to test the engine compression and, more importantly, how to interpret its test results.
With your test results, you'll quickly find out if a compression problem is causing an engine no-start problem or an engine misfire problem.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 1.7L Honda Civic DX: 2001, 2002, 2003, 2004, 2005.
- 1.7L Honda Civic EX: 2001, 2002, 2003, 2004, 2005.
- 1.7L Honda Civic GX: 2001, 2002, 2003, 2004, 2005.
- 1.7L Honda Civic HX: 2001, 2002, 2003, 2004, 2005.
- 1.7L Honda Civic LX: 2001, 2002, 2003, 2004, 2005.
Symptoms Of Low Or No Engine Compression
Engine compression problems usually cause one of two issues:
- An engine no-start problem.
- The engine starts but runs with a misfire or a rough idle condition.
If the engine does start, you'll see one or more of the following symptoms:
- Bad gas mileage.
- A heavier exhaust smell coming out of its tailpipe.
- Engine is not as peppy as it was once.
- Rough idle that goes away as soon as you accelerate the engine.
- One or more of the following misfire trouble codes:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
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 two recommendations:
1) Which one to buy: The engine compression tester that I have always used is the Actron CP7827 Compression Tester Kit. My only complaint about this engine compression tester is that it does not come with a case to store it in.
Engine Compression Gauge Testers
2) Where to buy: You can buy an engine compression tester just about anywhere, but you'll end up paying more for it (especially at your local auto parts store). The above links will help you comparison shop. I think you'll agree it's the better way to save money on the compression tester!
TEST 1: 'Dry' Engine Compression Test
You'll need to remove the spark plugs to test the engine's compression. When removing them, check for the following:
- Spark plug tube full of engine oil.
- Spark plug and spark plug boot soaked in engine oil.
- Any apparent damage or wear on the spark plug boot and spark plug.
If you find engine oil in the spark plug tube, replace the valve cover gasket and spark plug tube seals. You'll also need to replace any component that is oil-soaked.
If you don't have an engine compression tester, you can run down to your local auto parts store and either buy one or borrow one from them.
You can also buy one online. You can check out my recommendations here: Which Compression Tester Should I Buy?
IMPORTANT: Do not remove the spark plugs if the engine is hot. If the engine has been running for any amount of time, let it cool down completely before removing the spark plugs.
CAUTION: Take all necessary safety precautions. The engine has to be cranked to perform the engine compression test. Be careful and think safety all the time!
Okay, these are the test steps:
Disable the fuel system by removing the fuel pump relay.
This will prevent fuel from being injected into the cylinders as you crank the engine.
Remove the COP ignition coils.
Remove the 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!
Thread the engine compression gauge into the spark plug hole for the number 1 engine cylinder (this is the spark plug hole closest to the drive belt).
IMPORTANT: Hand tighten the compression gauge only! Do not use any type of tool to get it tight.
When the tester is set up, ask your helper to crank the engine. Your job is to keep your eye on the compression tester's gauge.
Once the needle on the gauge stops climbing, have your helper stop cranking the engine.
Write down the compression value on a piece of paper.
Include the number of the cylinder this reading belongs to.
Repeat steps 4 thru' 7 on the remaining cylinders.
Let's take a look at what your test results mean:
CASE 1: Low or no compression in 2 or all cylinders. This test result indicates a serious internal problem.
The most common issues would be:
- Blown head gasket.
- Broken timing belt.
- Engine threw a rod.
CASE 2: Low compression in one or more cylinders. Up 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.