I need to find out the health of my BMW engine as a diagnosis step. I am going to show you with full DIY steps on how to perform a compression test on your engine. The vehicle being used is my BMW Z3 with the M54 6 Cylinder engine that has a failed head gasket. There are specific steps to successfully perform a compression test. I will make it easy for you to be able to test your engine by following my method as shown in my video. I will also include descriptions of specifications for a compression test and general guidelines you can follow.
Compression testing can help you identify a specific cylinder or cylinders to focus on during your engine diagnosis.
I also include ways to help determine the reason why your compression test may be low and how to test your engine piston rings with a simple method.
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An engine makes power by compressing vaporized fuel and igniting it in a compressed state. The engine's compression can be measured using a compression gauge installed in the spark plug hole.
When piston rings wear out the compression required to efficiently burn the air to fuel mixture is reduced. After performing basic diagnosis it is important to perform a compression test. A compression test is designed to check the condition of the valve train and piston rings. Valves need to seal and close properly and the piston rings need to seal the bottom crankcase.
When would you need to perform a compression test:
Smoke from exhaust
Poor acceleration / vehicle sluggish
Misfire issues
Poor fuel economy
Adding more oil than normal Oil consumption
Or to get the general health of your engine
How to correctly perform a compression test:
If possible warm up your engine. Disable fuel and ignition. Remove and inspect spark plugs. Install compression gauge. Crank the engine over 3-5 times or seconds. Be consistent for each cylinder. Record your readings. Add oil to cylinder to check sealing of rings or for washed out cylinder walls.
Chapters:
00:00 Intro What Is A Compression Test
00:54 Ignition Coil Removal Plus Pro Tip
02:11 Disable Fuel System Steps
03:24 Spark Plug Removal Plus Pro Tip
04:49 Recommend Using a Battery Charger And Cover Any Possible Power Sources
05:06 Compression Testing Specifications Explained
05:39 Matching Up The Correct Compression Tester Fitting And Installing In Cyl. 1
06:46 Compression Testing Cylinders 1 through 6 With Pro Tips
09:49 REASONS TO PERFORM A COMPRESSION TEST
10:24 Evaluating The Compression Test Results
11:01 How To Test The Piston Rings Or Cylinder Wash Out
12:46 What Other Test Should You Perform -- Cylinder Leakage Test
14:33 Conclusion and Time To Walk Zion
