Testing the engine compression on your 1.6L Honda Civic (Civic Del Sol) is a pretty easy and simple affair, since the spark plugs are right on top of the engine. This tutorial will walk you through the entire process in a step-by-step fashion and will also help you interpret your test results.
Contents of this tutorial:
Symptoms Of Low Or No Engine Compression
An engine compression test will help you troubleshoot the root cause of:
- A misfire condition (engine miss, rough idle condition).
- Usually caused by very low compression in one cylinder.
- Or caused by uneven engine compression that varies more than 15% across all 4 cylinders.
- A 'cranks but does not start' condition.
- Usually caused by no compression on 2 or all 4 cylinders.
I'll go into some detail about these two in the next couple of paragraphs.
Having low or no engine compression in one cylinder on your 1.6L Honda Civic will cause your engine to miss at idle and you'll definitely feel there's something wrong when you accelerate the vehicle.
When this happens (low or no compression on just one cylinder) and your Honda vehicle is OBD II equipped (1996+), you'll see one of the following misfire diagnostic trouble codes:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
If your Honda Civic (Civic Del Sol) 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.
The next common scenario is having low or no engine compression on two ADJACENT engine cylinders and your Honda won't start. It'll crank but not start. This usually indicates that the head gasket has burned between the two cylinders.
If a blown head gasket is a concern, take a look at this tutorial: How To Test For A Blown Head Gasket (1995-2000 1.6L Honda Civic).
When you have a situation where you have no compression on ALL four cylinders, you'll see:
- The engine cranks very fast and this fast cranking speed is very noticeable.
- The ignition system is sparking all 4 spark plugs, so you know it's not an ignition system problem/issue.
- The fuel injectors spray fuel.
- You can confirm this with a Noid light test.
- Also, you can confirm this, although indirectly, by removing the spark plugs and checking to see if they are fuel soaked (fuel fouled).
- Fuel pump is working and providing pressure.
- The most common causes of this scenario, are:
- A blown head gasket.
- A broken timing belt.
- The engine thru' a rod.
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 1.6L Honda Civic.
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 these recommendations to you:
Disclosure: As an Amazon Associate, I earn from qualifying purchases. If my tutorials help you, using these links is an easy way to support the site at no extra cost to you. Thank you!
TEST 1: 'Dry' Engine Compression Test
If you don't have an engine compression test, you can buy one from your local auto-parts store or, if you have an AutoZone or O'Reilly Auto Parts store nearby, you can rent one from them (they'll rent it for free, after you leave them a cash deposit for the tool, which you'll get back once you return it).
If you need help deciding where to buy one or which one to buy, take a look at my recommendations: Which Compression Tester Should I Buy?
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!
IMPORTANT: Do not remove the spark plugs if the engine is hot! If the engine has been running for any length of time, then let it cool down completely before removing the spark plugs.
This is what you'll need to do:
- 1
Disable the fuel system. You can do this by disconnecting all of the fuel injectors.
This will prevent fuel from being injected into the engine as you crank the engine. - 2
Disable the ignition system. You can do this by disconnecting the distributor from its electrical connectors.
This will prevent spark from being created and sent to the spark plug wires while cranking the engine. This will also prevent damage to the ignition coil. - 3
Disconnect all of the spark plug wires from the spark plugs.
- 4
Remove all four 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! - 5
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).
NOTE: Hand tighten the compression gauge only! Do not use any type of tool to get it tight. - 6
When you're ready, have a helper crank up your Honda as you observe the needle on the compression tester's gauge.
- 7
Once the needle on the gauge stops climbing, have him or her stop cranking the engine.
- 8
Record this compression reading on a piece of paper. Include the number of the cylinder this reading belongs to.
- 9
Repeat steps 5 thru' 8 on the other 3 cylinders.
Let's interpret the results of your compression test:
CASE 1: Low or no compression in 2 or all 4 cylinders. This test result indicates a serious internal problem.
The most common issues would be:
- Blown head gasket. For further testing, go to: How To Test For A Blown Head Gasket (1995-2000 1.6L Honda Civic).
- Broken timing belt. For further testing, go to: How To Test For A Broken Timing Belt (1995-2000 1.6L Honda Civic).
- 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 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
A low compression value in one or more cylinders can cause a misfire problem or a rough idle problem -depending on how low the value is.
To be a bit more specific, a low compression value doesn't necessarily mean that that cylinder is causing a problem.
It's when the low compression value is lower than 15% of the highest one, that that cylinder will cause a misfire problem or a rough idle problem.
The cool thing is that we can easily find out if the low compression values are causing an engine performance problem or not.
To find out, we need to figure out if the low compression values are lower than 15% of the highest compression value you got.
You can do this (figuring out the 15%) in 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 (at: easyautodiagnostics.com).
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 I got 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
In this test step you're gonna' add about two tablespoons of oil to the engine cylinder that showed a low compression reading in the 'dry' compression test.
The engine oil that you're gonna' add to the cylinder will help determine if the low cylinder pressure or pressures you recorded in the 'dry' compression test are caused by worn piston rings or worn cylinder head valves.
Depending on whether the compression pressure rises (on your compression tester) or not, you'll be able to say that the problem lies in the piston's rings or in the cylinder head valves.
OK, this is what you need to do:
- 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
Install the compression tester onto the cylinder.
Do not use any type of tool to tightened the compression tester. Hand tight is fine. - 3
When all is set up, have your helper crank the engine.
- 4
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.
CASE 1: The compression value shot up. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your 1.6L Honda Civic.
CASE 2: The compression value stayed the same. This confirms that the problem is in the cylinder head valves.
More 1.6L Honda Civic Tutorials
You can find all of the 1.6L Honda articles here: 1.6L Honda Civic Index Of Articles.
Here's a sample of the tutorials you'll find in the index:
- How To Test For A Blown Head Gasket (1995-2000 1.6L Honda Civic).
- How To Test The Alternator (1996-2000 1.6L Honda Civic).
- Testing Shift Control Solenoid Valves A and B (1996-2000 1.6L Honda Civic).
- How To Troubleshoot A No Start (1995-2000 1.6L Honda Civic).
- How To Test The Igniter, Ignition Coil Accord, Civic, CRV, and Odyssey (at: easyautodiagnostics.com).
If this info saved the day, buy me a beer!
