1st Gen Compression Checking Your Rotary Engine

How to Compression Check Your Rotary Engine​


Time Investment: ~30 minutes
Difficulty: Low

Tools Used:
Compression Tester
13/16 Spark Plug Socket
Ratchet
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Information:
  • For this guide it is implied that you have a Rotary specific compression tester.
  • You can perform the compression test warm or cold, but for accurate results it's recommended to be warm.
  • You can use a normal piston compression tester, but must remove the Schrader valve (requires two people or a remote starter).
  • If using the piston compression tester method, each needle pulse (bounce) will be that faces PSI.

Steps:
1. Start the car and let it warm up to operating temperature (~185f) before shutting it off.
2. Disable the vehicles ignition and fuel system
  • Remove the EGI (Electronic Gasoline Injection) fuse (pictured below is the FC location).
    • Remove the Fuel Pump fuse for Carbureted FBs and start the vehicle so it will suck in the remaining fuel in the bowl before dying.
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  • For the FB chassis, remove the coil wires from the distributor
  • For the FC Chassis, unplug the CAS (Crank Angle Sensor)
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  • For the FD Chassis, unplug the ignition coil connector located on the backside of the power steering pump.
3. Remove both trailing spark plugs from the engine
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4. Input the compression tester sensor into the front spark plug hole
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5. Connect the sensor to the compression tester and turn the tester on
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6. With the gas pedal fully depressed, begin cranking the engine until the compression tester displays readings
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7. Repeat for rear rotor housing
 
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