Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSBMW2003Z4 3.0 3, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMENGINE CONTROLS - BASIC DIAGNOSTIC PROCEDURESFUEL SYSTEMFUEL VOLUME & PRESSURENOTES
2003 BMW Z4 3.0 3, Automatic
Fuel Volume & Pressure: Notes
2003 BMW Z4 3.0 3, AutomaticSECTION Notes
NOTE:
The following procedure is for 6-cylinder engines, and may apply to other engines.
Begin basic fuel system diagnosis by determining fuel system pressure.
- Remove engine cover to gain access to fuel lines. Prepare Pressure Testing Kit (135220) which consists of Check Valve (135221) and Adapter (135222). Remove dust cap from measuring valve on fuel rail. Connect check valve and gauge to fuel rail. 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) 6-Cylinder & V8 50 (3.5) 1.85 (0.9) V12 (1) (1) (1) Information is not available.
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:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.