1990 Infiniti M30FACTORY OEM SERVICE PROCEDURE

Engine Compression

Check engine compression with engine at normal operating temperature at specified cranking speed with all spark plugs removed and throttle wide open. Release fuel pressure. To release fuel pressure, remove fuel pump fuse (located in fuse block) and start engine until it stalls. Crank engine 2-3 times to release residual pressure. Disconnect distributor harness connector.

Crank engine at least 6 revolutions to determine engine compression. Compression reading should be as specified. See ENGINE COMPRESSION table.

M30 ENGINE COMPRESSION

Standard psi (kg/cm2 ) Minimum psi (kg/cm2 ) RPM
173 (12.2) 128 (9.0) 300
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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