Fuel Pressure: Notes

Basic fuel system diagnosis should begin with determining fuel system pressure.

1. On 318, 325 and 525 Series, remove air intake duct to gain access to fuel lines near throttle body. On all models, 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.

Fig 1: Checking Fuel Pump Pressure & Delivery Rate