Fuel Pressure: Notes

Begin basic fuel system diagnosis by determining fuel system pressure.

1. Remove air intake duct to gain access to fuel lines near throttle body. Connect Pressure Gauge (13-3-060) and "T" Fitting (13-3-064) in fuel lines in front of fuel pressure regulator. See Fig 1 . Block (plug) fuel return line with Fuel Hose Clamp (13-3-010).
2. Remove fuel pump relay. See DME & FUEL PUMP RELAY LOCATION table. Using Fuel Pump Relay Bridging Caliper (61-3-050) or jumper wire, connect (bridge) terminals No. 87 and 30 at fuel pump relay socket. See Fig 1 . This will turn fuel pump on.
3. Check fuel pump delivery pressure. To check fuel pump delivery rate, disconnect fuel return line. Install extension hose and hold end of hose in Graduated Glass Container (13-3-020). See Fig 1 . Check fuel pump delivery rate. See FUEL PUMP PERFORMANCE table.

Fig 1: Checking Fuel Pump Pressure & Delivery Rate - 1 Of 4 (325i Shown)

Fig 2: Checking Fuel Pump Pressure & Delivery Rate - 2 Of 4 (525i Shown)

Fig 3: Checking Fuel Pump Pressure & Delivery Rate - 3 Of 4 (325i Shown)

Fig 4: Checking Fuel Pump Pressure & Delivery Rate - 4 Of 4 (325i Shown)