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Home >> Isuzu >> 1990 >> Impulse Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments - EFI >> Engine Compression

Engine Compression

Check engine compression with engine at normal operating temperature. Disconnect fuel pump relay from fuse/relay box. See FUEL PUMP RELAY LOCATION  table. Remove all spark plugs, hold throttle lever wide open, and operate engine at cranking speed (300 RPM). Crank engine a minimum of 4 compression strokes.

FUEL PUMP RELAY LOCATION

Model Location
Amigo & Pickup On Right Fender Panel, Near Battery
Impulse On Left Fender Panel, Behind Battery
Trooper On Left Firewall, Near Brake Master Cylinder
COMPRESSION SPECIFICATIONS

Application Specification
Compression Ratio
Amigo & Pickup
2.3L & 2.6L 8.3:1
Impulse 1.6L 9.8:1
Trooper
2.6L 8.3:1
2.8L 9.8:1
Compression Pressure
Amigo & Pickup
2.3L & 2.6L (1) 142-171 psi (10-12 kg/cm2 )
Impulse 1.6L (2) 185 psi (13 kg/cm2 )
Trooper
2.6L (1) 155-157 psi (10.8-11 kg/cm2 )
2.8L (3) 100 psi (7.0 kg/cm2 )

(1) Minimum pressure is 114 psi (8 kg/cm2 ).
(2) Minimum pressure is 128 psi (9 kg/cm2 ).
(3) Minimum pressure should be at least 70 percent of highest cylinder.