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 Geo Tracker LSi, AutomaticFACTORY OEM SERVICE PROCEDURE
Chart A-7, Fuel System Pressure Test: Notes
Fuel pump delivers fuel to fuel rail and fuel injectors, where fuel pressure is maintained by pressure regulator.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Release fuel pressure before disconnecting fuel lines. Operate fuel pump by installing fused jumper wire between Black/White and Pink/Black wire terminals on fuel pump relay and turning ignition on. Fuel pump relay is mounted on ECM, located under left side of instrument panel, near kick panel.
- Restricted fuel flow can cause fuel pressure to decrease, resulting in driveability problem.
- Restricting fuel return hose allows fuel pump to obtain maximum fuel pressure. With ignition on, fuel pressure should be greater than 56.9 psi (4.0 kg/cm2 ).
- This determines if high fuel pressure is caused by fuel hose restriction or defective pressure regulator.
- This checks for a leaking 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.