Fuel Pressure: Notes

1992 BMW 318isSECTION Notes

Begin basic fuel system diagnosis by determining fuel system pressure.

  1. On 318 Series, 325 Series and 525i, 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. See FUEL PUMP PERFORMANCE table.
FUEL PUMP PERFORMANCE

Application Pressure psi (kg/cm2 ) Min. Vol. in 30 sec. Pts. (L)
All Models 43 (3) 1.85 (0.9)
Fig 1: Checking Fuel Pump Pressure & Delivery Rate
G91A16485
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.