How To Test Engine Compression (2001-2004 2.0L Ford Escape)

The one thing that makes testing engine compression a piece of cake on the 2.0L Ford Escape is that the spark plugs are easy to get to and remove.

In this tutorial, I'm going to show you how to do the compression test and, more importantly, how to interpret your results.

I'll also explain how to do a wet compression test, so if you've got a cylinder with low or zero PSI, you can pinpoint what's causing it.

You can find this tutorial in Spanish here: Cómo Probar La Compresión Del Motor (2.0L Ford) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 2.0L Ford Escape: 2001, 2002, 2003, 2004.
• 2.0L Mazda Tribute: 2001, 2002, 2003, 2004.

2.0L FORD FOCUS COMPRESSION TEST: For the 2.0L SOHC/DOHC Ford Focus, go to this tutorial:

• How To Test Engine Compression (2000-2010 2.0L Ford Focus) (at: troubleshootmyvehicle.com).

2.0L FORD ESCORT COMPRESSION TEST: For the 2.0L SOHC/DOHC Ford Escort, go to:

• How To Test Engine Compression (1997-2003 2.0L Ford Escort, Mercury Tracer).

Symptoms Of Low Or No Cylinder Compression

Engine compression problems fall into 2 basic categories:

• Low engine compression in one or two cylinders.
• No compression in all cylinders.

Now, if your Ford Escape 2.0L engine has a cylinder compression issue, here are some of the engine performance problems you may see.

• Engine cranks but doesn't start.
• Blue smoke coming out of the tailpipe.
• Rough idle (engine misfires).
• Cylinder misfire setting one or more of the following codes:
  • P0300: Random Cylinder Misfire.
  • P0301: Cylinder #1 Misfire.
  • P0302: Cylinder #2 Misfire.
  • P0303: Cylinder #3 Misfire.
  • P0304: Cylinder #4 Misfire.
• Bad gas mileage.
• Engine 'misses' at idle but 'miss' disappears as you accelerate.
• Check engine light is illuminated with a MAP sensor trouble code (even tho' the MAP sensor is good).

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 Compression Test

One of the things that you need to watch out for as you're disconnecting the spark plug wires from the spark plugs and removing the spark plugs is to see if the spark plug wire boots and spark plugs are soaked or swimming in oil.

If you do find this issue, you've got a valve cover gasket and its spark plug tube seals leaking oil into the spark plug tube wells, and this is something that you'll need to fix.

This particular type of problem is common on the 2.0L DOHC engine and if left unresolved, it can cause a cylinder misfire issue, if it isn't causing one already.

CAUTION: Take all necessary safety precautions as you work around a cranking engine. Keep hands and any loose clothing away from moving parts. Be careful and think safety all of the time.

IMPORTANT: Your 2.0L Ford Escape's cylinder head is made of aluminum, so don't remove the spark plugs with a hot engine. Removing the spark plugs from a hot engine can/will damage the spark plug hole threads in the aluminum cylinder head.

OK, to get started this is what you'll need to do:

1. 1

   Disable the ignition system by disconnecting the ignition coil from its electrical connector.
   
   NOTE: This will prevent the ignition coil from sparking during the test.

2. 2

   Disable the fuel system by disconnecting the fuel injectors.
   
   Disabling the fuel system will prevent fuel from being injected into each cylinder when the test is performed.

3. 3

   Remove the spark plugs 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.

4. 4

   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.

5. 5

   Have your helper crank the engine till the needle on the compression gauge stops climbing.

6. 6

   Record on paper the value at which the needle stopped and the number of the engine cylinder on a piece of paper.

7. 7

   Release the pressure on the gauge and repeat steps 5 and 6 one more time.

8. 8

   Check the compression of the remaining cylinders.

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

CASE 1: You got 0 PSI on all 4 cylinders. This test result lets you know that the engine has suffered one of the following conditions:

• A broken timing belt.
• A blown head gasket.
• A blown engine.

Any compression value below 100 PSI (even if it does not 0 PSI) means internal mechanical engine trouble.

CASE 2: The compression values from each cylinder are slightly different from one another. Up to a certain point this could be normal.

If the compression value variation is within a certain range, then the engine won't suffer any performance problems. What will cause a problem is if the values vary too much. The cool thing is that we can find out if the variations in the values, you wrote down, indicate a problem (with that cylinder) or not. Go to: Interpreting The Results Of The Engine Compression Test.

CASE 3: All 4 cylinders have similar compression values. This test result tells you the internal condition of the engine is solid.

When the compression numbers are close to each other, you can be confident the pistons, piston rings, cylinder walls, and valves are all sealing like they should. In other words, the internals of the engine are in tip-top shape.

If you're troubleshooting a no-start or a performance problem (like a cylinder misfire), then engine compression isn't what's causing it. You'll need to keep looking at other systems (ignition, fuel, sensors, etc.) to find the root cause of the issue.

Interpreting The Results Of The Engine Compression Test

A little variation between cylinder compression readings is normal and usually won't affect the way the engine runs.

But once one or more cylinders fall below 15% of the highest reading, that's when drivability problems like rough idle or misfires start to show up.

So how do you know if the numbers from your test cross that line? The easiest way is to plug them into my online calculator here: Online Low Engine Compression Calculator. Or, if you want to work it out yourself, here's the math:

• STEP 1: Take the highest compression reading and multiply it by 0.15 (15% in decimal form).
• STEP 2: Round the result to the nearest whole number (for example: 25.6 becomes 26).
• STEP 3: Subtract that number from your highest compression reading.
• ANSWER: The final number is the lowest compression value a cylinder can have before it's considered out of spec.

Here's an example to show you exactly how this works using real compression readings:

Cylinder	Pressure
#1	175 PSI
#2	170 PSI
#3	165 PSI
#4	120 PSI

The next step is to do the math:

• STEP 1: 175 x 0.15 = 26.25.
• STEP 2: 26.25 = 26.
• STEP 2: 175 - 26= 149.
• ANSWER: 149 PSI is the lowest possible compression value.

Based on the calculation, we can now conclude that cylinder #4, producing only 120 PSI, is the weak link in the chain and the one causing the misfire.

In your compression test results, to see if the lowest number you got is OK, you'll do the same calculation —only this time using the highest reading from your own test instead of the sample values I used.

The next step is figuring out why that cylinder's compression is low (or zero). Head over to: TEST 2: Wet Compression Test

TEST 2: Wet Compression Test

That low compression reading you got in TEST 1 usually comes down to one of two things:

• Worn piston rings.
• Bad cylinder head valves.

The good news is, you don't have to tear the engine apart to confirm which one it is. All you need to do is add a small amount of motor oil to the low compression cylinder and repeat the compression test (this is called a wet compression test).

What you're looking for after adding the oil and running the test again is:

• The compression value shoots up: That means the low reading in TEST 1 is caused by worn piston rings.
• The compression doesn't change: That tells you the problem is due to severely worn or damaged intake/exhaust valves in that cylinder.

OK, this is what you'll need to do:

1. 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. 2

   Once you've added the oil, install the compression gauge, and as before just hand tighten it.

3. 3

   Now, have your helper crank the engine till the needle stops climbing on the compression gauge.

4. 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.
   
   Whatever value your compression tester reads, write it down again.

5. 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 cylinder's compression increased after adding oil. This confirms that the low compression reading you got in the dry test is being caused by worn piston rings.

The reason the compression number climbs is simple: the motor oil you added temporarily helped the piston rings seal tighter against the cylinder wall. This type of test result only shows up when the problem is internal wear on the rings themselves.

CASE 2: The cylinder's compression stayed the same after adding oil. When the reading doesn't improve, even with oil added, you can conclude that the low or 0 PSI compression result in that cylinder is due to intake/exhaust valve damage.

More 2.0L Ford Escape Diagnostic Tutorials

You can find a complete list of 2.0L Ford Escape (Mazda Tribute) tutorials in this index:

• 2.0L Ford Escape Index Of Articles.

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

• How To Test The Throttle Position Sensor (2001-2004 2.0L Ford Escape).
• How To Test The Fuel Injectors (2001-2004 2.0L Ford Escape).
• Oxygen Sensor Heater Test -P0135 (2001-2004 2.0L Ford Escape).
• How To Test The Starter Motor (2001-2004 2.0L Ford Escape).