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.

1991 Isuzu Impulse RSFACTORY OEM SERVICE PROCEDURE

Fuel Pump (Fuel Injected)

FUEL PUMP PERFORMANCE

Application

Unregulated Pressure psi (kg/cm² )

Regulated Pressure psi (kg/cm² )

Impulse

Non-Turbo

⁽¹⁾ 35-38 (2.4-2.7)

⁽²⁾ 25-30 (1.7-2.1)

Turbo

⁽¹⁾ 39-47

⁽²⁾ Slight Drop

Stylus

35-38 (2.4-2.7)

25-30 (1.7-2.1)

⁽¹⁾	With ignition on and vacuum hose disconnected from pressure regulator.

⁽²⁾	With engine at idle or with 12-14 in. Hg vacuum manually applied to pressure regulator.

Factory Service Tools

Use the Manual With the Right Hardware

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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.