How to Check Compression on a First Generation Mitsubishi Eclipse
Gather the tools required to complete the compression test., Once all tools are gathered, find a place in which you would be performing the compression test, driveway, garage, etc., Once vehicle has reached operational temperature shut the engine...
Step-by-Step Guide
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Step 1: Gather the tools required to complete the compression test.
You will need a ratchet, spark plug socket, and a compression tester which you can easily rent from any auto parts store.
You will also need some sort of repair manual, Haynes, Etc. -
Step 2: Once all tools are gathered
As well as the vehicle in which you would be doing the test on.
Once you obtain the place and all the tools, and the vehicle, let the vehicle get up to operational temperature.
NOTE:
You do not want to do a compression test on a cold engine, metal expands when hot and allows everything to fully operate.
This way all the parts expand on heat and keep a better compression. , Once the hood of the car is open locate the spark plugs.
There will be four of them since this is a 4 cylinder motor, and all four of them will be sitting on top of the vale cover ,, NOTE- Doing this will eliminate shock when doing test! , Make sure the gauge can rest somewhere safe where it will not fall while you are cranking the car. , Make sure you have a (WOT) " throttle should be wide open".
You should be able to count how many times the motor tries to turn over.
This is known as compression strokes.
Once you let it turn over, turn the key off and check the gauge. ,, The readings should be no more or less than 20% of the others.
The readings should be anywhere from 155+ across the board, depending on mileage. ,, This will show exactly where leaking is occurring and how bad it is. , Double check everything is plugged back in before you attempt to start the vehicle! -
Step 3: find a place in which you would be performing the compression test
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Step 4: driveway
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Step 5: garage
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Step 6: Once vehicle has reached operational temperature shut the engine off
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Step 7: and open up the hood of the car
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Step 8: Use caution as to motor will be warm and certain components could burn skin on contact
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Step 9: Such as exhaust manifold.
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Step 10: Remove all of the spark plugs from the engine
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Step 11: Disconnect the primary wires from the distributor and make sure the main harness coming from the distributor is disconnected from the motor.
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Step 12: Install the compression gauge in the number one spark plug hole.
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Step 13: Crank the engine over at least six compression strokes.
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Step 14: Record what the gauge reads and proceed this for each cylinder head/ spark plug hole.
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Step 15: Once finished with all four readings compare the readouts with each cylinder.
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Step 16: If the compression is high
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Step 17: the combustion chambers are probably built up with carbon deposits
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Step 18: if the case
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Step 19: then the cylinder head needs to be removed and de-carbonized
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Step 20: If the compression is lower
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Step 21: or varies greatly between cylinders
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Step 22: perform a leak down test
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Step 23: or have a shop perform one.
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Step 24: Once test is finished
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Step 25: make sure you screw all four spark plugs back in
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Step 26: and hook up the distributor harness back to the engine.
Detailed Guide
You will need a ratchet, spark plug socket, and a compression tester which you can easily rent from any auto parts store.
You will also need some sort of repair manual, Haynes, Etc.
As well as the vehicle in which you would be doing the test on.
Once you obtain the place and all the tools, and the vehicle, let the vehicle get up to operational temperature.
NOTE:
You do not want to do a compression test on a cold engine, metal expands when hot and allows everything to fully operate.
This way all the parts expand on heat and keep a better compression. , Once the hood of the car is open locate the spark plugs.
There will be four of them since this is a 4 cylinder motor, and all four of them will be sitting on top of the vale cover ,, NOTE- Doing this will eliminate shock when doing test! , Make sure the gauge can rest somewhere safe where it will not fall while you are cranking the car. , Make sure you have a (WOT) " throttle should be wide open".
You should be able to count how many times the motor tries to turn over.
This is known as compression strokes.
Once you let it turn over, turn the key off and check the gauge. ,, The readings should be no more or less than 20% of the others.
The readings should be anywhere from 155+ across the board, depending on mileage. ,, This will show exactly where leaking is occurring and how bad it is. , Double check everything is plugged back in before you attempt to start the vehicle!
About the Author
Victoria Vasquez
Creates helpful guides on DIY projects to inspire and educate readers.
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