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.
1988 Chevrolet Hi-Cube 5.7 M, 475/M40FACTORY OEM SERVICE PROCEDURE
Opening Pressure Test
- Open tester shutoff valve 1/4 turn. Slowly depress tester lever and observe gauge. Note pressure at which needle of pressure gauge stops. Some injectors may pop while other injectors may drip (this is not a leak).
- Opening fuel pressure should not fall less than the lowest limit of 1500 psi (105 kg/cm2 ). Replace any injector which does not meet lowest acceptable pressure. Release tester pressure.
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.
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