Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1998 Isuzu Trooper S, AutomaticFACTORY OEM SERVICE PROCEDURE
Fuel Pump Pressure Test
NOTE:
Begin basic fuel system diagnosis with testing fuel pressure.
- Turn ignition off. Ensure A/C is off (if equipped). Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE . Attach Fuel Pressure Gauge Set (J-34730-1 ) to fuel rail or fuel supply line. See Fig 1 . Turn ignition on. Allow fuel pump to run for about 2 seconds. Check fuel pressure. See FUEL PUMP PERFORMANCE .
- With engine at normal operating temperature, turn ignition on and let fuel pressure build to maximum pressure. Start engine and observe pressure. See FUEL PUMP PERFORMANCE . If pressure drop is as specified, system is operating properly. If pressure does not drop as specified, see appropriate FUEL SYSTEM DIAGNOSIS procedure. Locate and repair leak or restriction in fuel system.
FUEL PUMP PERFORMANCE
| Application | Specification | |
|---|---|---|
| Amigo, Rodeo, Passport, Trooper & SLX | ||
| Operating Pressure | 42-55 psi (3.0-3.9 kg/cm2 ) | |
| Pressure Drop | 3-15 psi (0.2-1.1 kg/cm2 ) | |
| Hombre | ||
| Operating Pressure | 41-47 psi (2.9-3.3 kg/cm2 ) | |
| Pressure Drop | 3-10 psi (0.2-0.7 kg/cm2 ) | |
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:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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