5b - Fuel System Leakdown Test (Fuel Pump)

CAUTION:
^ Do not allow smoking or the use of open flames in the area where work on the fuel system is taking place. Anytime work is being done on the fuel system, disconnect the negative battery cable, except for those tests where battery voltage is required.
^ Whenever fuel line fittings are loosened or removed, wrap a shop cloth around the fitting and have an approved container available to collect any fuel.




1. Relieve fuel system pressure. (Refer to "Relieving Fuel Pressure" procedure.) Service and Repair
2. Disconnect fuel feed and return line at fuel rail.




3. Connect fuel flow/pressure adapter (SA9127E-7) inlet to fuel feed line and fuel flow/pressure adapter outlet to fuel return line.
a. Close valve on outlet side of tool.
b. Connect pressure gauge to fuel flow/pressure adapter.

IMPORTANT: Battery must be at a minimum of 12 volts when performing any fuel system tests. Charge battery before proceeding if below 12 volts.

4. Energize fuel pump for a minimum of 10 seconds. (Refer to "Energizing the Fuel Pump" procedure.) Component Tests and General Diagnostics
a. Record fuel pressure.
b. Shut fuel pump Off.
c. Wait five minutes.




5. Record fuel pressure and subtract from pressure recorded in Step 4. (Repeat this procedure a minimum of two times.)
6. Compare pressure loss (decay) to published specification.
7. Refer to "Fuel System Diagnostic Chart" and use test result to make appropriate decision.