FixVault

Engine Compression

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1998 Mazda Protege, 1998 Mazda Millenia, 1998 Mazda MPV, 1998 Mazda B4000, and 1998 Mazda B3000. However, it is still accessible from the selected car via links, so may be relevant.

Warm engine to normal operating temperature. Remove all spark plugs. Disconnect ignition coil primary wire connector. Hold throttle plate fully open. Crank engine and note compression pressure.

COMPRESSION RATIO

Application Specification
B2500 9.2:1
B3000 9.0:1
B4000 9.0:1
Millenia
2.3L 10.0:1
2.5L 9.2:1
MPV 8.5:1
Protege
1.5L 9.4:1
1.8L 9.0:1
626
2.0L 9.0:1
2.5L 9.5:1
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 ).