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.
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HOMESERVICE MANUALSPONTIAC1987FIERO BASE, STANDARD, MG3REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSIS2.8L PFI TESTS W/CODESDIAGNOSTIC CHARTSCHART A7 - FUEL SYSTEM DIAGNOSISTEST STEPS FOR CHART 2 OF 2
1987 Pontiac Fiero Base, Standard, MG3
Test Steps For Chart 2 Of 2
1987 Pontiac Fiero Base, Standard, MG3SECTION Test Steps For Chart 2 Of 2
- If fuel pressure is less than 40 psi (2.8 kg/cm2
) check the following:
- System has regulated pressure but pressure is less than 40 psi (2.8 kg/cm2 ). Amount of fuel to injectors okay, but pressure is too low. Fuel system will run lean and may set Code 44. Also, vehicle is hard starting cold with overall poor performance.
- Restricted fuel flow that causes pressure drop. Normally a vehicle with a fuel pressure of less than 24 psi (1.6 kg/cm2 ) at idle will not be driveable, however, if the pressure drop occurs only while driving, the engine will normally surge then stop as pressure begins to drop rapidly.
- Restricting the fuel return line allows the fuel pump to develop its maximum pressure (dead head pressure). When battery voltage is applied to the pump test terminal or fuel pump relay, pressure should be greater than 60 psi (4.1 kg/cm2 ).
- This test determines if the high fuel pressure is due to a restricted fuel return line or a pressure regulator problem.
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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.