How do I do a compression test?

Remove the spark plug, screw in a compression gauge, crank the engine 5-7 times. Compare all cylinders — they should be within 10% of each other.

What is normal compression?

Most gasoline engines should read 125-180 PSI per cylinder. Below 100 PSI indicates a problem.

High Severity

Engine System

Cylinder 2 is not contributing adequate power.

Common Fix

Repair cylinder 2 issue

Estimated Cost (DIY)

$40 - $500

Bad injectorlikely

Low compressionpossible

Ignition faultpossible

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How do I do a compression test?: Remove the spark plug, screw in a compression gauge, crank the engine 5-7 times. Compare all cylinders — they should be within 10% of each other.
What is normal compression?: Most gasoline engines should read 125-180 PSI per cylinder. Below 100 PSI indicates a problem.

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