5A - Fuel System LEAKDOWN Test

TOOLS REQUIRED

SA9127E Gauge Bar Set

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.

CAUTION: 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.

Fig 1: Connecting Fuel Flow/Pressure Adapter

Courtesy of GENERAL MOTORS CORP.

Relieve fuel system pressure. Refer to FUEL SYSTEM PRESSURE RELIEF .
Connect Gauge Bar Set SA9127E to fuel pressure test port.
IMPORTANT: Battery must be at a minimum of 12 volts when performing any fuel system tests. Charge battery before proceeding if below 12 volts.
Energize fuel pump for a minimum of 10 seconds. (Refer to ENERGIZING THE FUEL PUMP .)
1. Record fuel pressure.
2. Shut fuel pump Off.
3. Wait five minutes.
Record fuel pressure and subtract from pressure recorded in Step 3 . (Repeat this procedure a minimum of two times.)
Compare pressure loss (decay) to specification.

Fig 2: Fuel System Leakdown Test Specification
Courtesy of GENERAL MOTORS CORP.
Refer to FUEL SYSTEM DIAGNOSIS - FUEL SUPPLY CHART and use test result to make appropriate decision.