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.
Chart A7 (2 Of 2) - Fuel System Diagnosis (5.0/5.7L)
1987 Pontiac 6000 SafariSECTION Chart A7 (2 Of 2) - Fuel System Diagnosis (5.0/5.7L)
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- If fuel system has pressure, but less than 41 psi (2.8 kg/cm2
), perform the following tests:
- Regulated pressure, but less than 41 psi (2.8 kg/cm2 ). Amount of fuel to injectors is okay but pressure is too low. System will be lean running and may set Code 44. Can also be hard starting cold and poor overall performance.
- Restricted flow causing pressure drop. Normally, a vehicle with a fuel pressure of less than 24 psi (1.7 kg/cm2 ) at idle will not be driveable. If the pressure drop occurs only while driving, the engine will surge and then stop as pressure drops rapidly.
- Restricting the fuel return line allows the fuel pump to develop its maximum pressure. When battery voltage is applied to the ALCL pump terminal "G", pressure should be approximately 60 psi (4.2 kg/cm2 ).
- This test determines if the high fuel pressure is due to a restricted fuel return line or a pressure regulator problem.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.