Mechanical Inspection: Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.

WARNING: DO NOT use ignition switch during compression tests on fuel injected vehicles. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking, which can create a fire hazard or contaminate the engine's oiling system.

COMPRESSION SPECIFICATIONS

Application

Minimum psi (kg/cm² ) @ RPM

Standard psi (kg/cm² ) @ RPM

B2500

N/A

⁽¹⁾

B3000 & B4000

N/A

⁽¹⁾

Millenia ⁽²⁾

2.3L

121 (8.5) @ 250

164 (11.5) @ 250

2.5L

132 (9.3) @ 300

189 (13.3) @ 300

MPV

121 (8.5) @ 300

164 (11.5) @ 300

Protege ⁽²⁾

1.5L

146 (10.3) @ 300

195 (13.7) @ 300

1.8L

139 (9.8) @ 300

185 (13.0) @ 300

626 ⁽²⁾

2.0L

119 (8.4) @ 300

171 (12.0) @ 300

2.5L

141 (9.9) @ 250

203 (14.3) @ 250

⁽¹⁾	Lowest compression reading should not be less than 75 percent of highest compression reading.

⁽²⁾	Difference between cylinders should not be more than 28 psi (2.0 kg/cm² ).