Fuel Pressure: Notes
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 1998 BMW Z3, 1998 BMW M3, 1998 BMW M Roadster, 1998 BMW 740iL, and 1998 BMW 740i. However, it is still accessible from the selected car via links, so may be relevant.
Begin basic fuel system diagnosis by determining fuel system pressure.
- Remove engine cover to gain access to fuel lines. Connect Pressure Gauge (133060) and "T" Fitting (133064) in fuel lines in front of fuel pressure regulator. Block (plug) fuel return line with Fuel Hose Clamp (133010).
- Remove fuel pump relay. See DME & FUEL PUMP RELAY LOCATION table. Using Fuel Pump Relay Bridging Caliper (613050) or jumper wire, connect terminals No. 87 and 30 at fuel pump relay socket. See Figure . This will turn fuel pump on.
- Disconnect fuel return line. Install extension hose and hold end of hose in Graduated Glass Container (133020). Check fuel pump delivery rate. See FUEL PUMP PERFORMANCE
table.FUEL PUMP PERFORMANCE
Application Pressure psi (kg/cm2 ) Min. Vol. In 30 Sec. Pts. (L) 4-Cylinder 43 (3) 1.85 (0.9) 6-Cylinder & V8 50 (3.5) 1.85 (0.9)