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.
5 - Fuel System LEAKDOWN Test
TOOLS REQUIRED: SA9127E Gage Bar Set
The fuel system leakdown test will determine if the fuel system is able to hold fuel pressure when the fuel pump is not operating. The system must hold pressure to assure that the fuel supply circuit (fuel lines, filter/regulator, and fuel rail) is full of fuel. When the fuel supply is completely charged, fuel will be available at the injectors as soon as the ignition is turned on.
- Remove air induction tube.
- Relieve fuel system pressure. Refer to RELIEVING FUEL PRESSURE .
- Connect Gage Bar Set SA9127E to fuel pressure port.NOTE: Battery must be at a minimum of 12 volts when performing any fuel system test. Charge battery before proceeding if below 12 volts.
- Energize fuel pump. Refer to ENERGIZING THE FUEL PUMP for a minimum of 10 seconds.
- Shut fuel pump OFF and wait 5 minutes.
- Record fuel pressure and subtract from pressure recorded in step 1.
- Compare pressure loss (decay) to published specification.
- Refer to FUEL SYSTEM DIAGNOSIS - FUEL SUPPLY CHART and use test result to make appropriate decision.
NO RELATED
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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.