REPLACING FUEL PUMP Checking Fuel Pump of Stopped Engine: Disconnect plugs at air flow sensor. Connect wire 36 with 39 in plug. Turn on ignition. |  |
From 1980 Models: Pull off plug (1) on double relay. Connect term. 8 (88d) in pump relay socket with B +. Fuel pump runs. A soft click indicates that pump relay is good. A soft buzz indicates the fuel pump is running. If no fuel is delivered in spite of this, pressure relief or check valve in fuel pump is defective. |  |
A) BMW 630 i: Disconnect wire plugs. Important: Don´t pull on wires. Installation: Tab of plug in groove. Detach and plug (clamp or similar item) suction hose. Detach hose at expansion tank. Remove delivery pump with expansion tank. |  |
Detach delivery pump at expansion tank. Important: Never open delivery pump. |  |
B) BMW 633 i: Disconnect ground wire at battery. Unscrew wires on fuel pump. Detach hose on fuel filter. Unscrew nut (25). Installation: Use a new squeeze hose clamp. Conn. + = M 4 nut and green/violet wire Conn. - = M 5 nut and brown wire |  |
Detach hose on fuel pump. Important: Pinch fuel line shut with Special Tool 13 3 010. Unscrew nuts (26 and 27). Remove holder with fuel pump, fuel filter and expansion tank. |  |
Unscrew screw (28). Detach hose (29) on expansion tank. Remove fuel pump. Installation: Use a new squeeze hose clamp. |  |
Vehicles after change point in 1982 REMOVING AND INSTALLING FUEL PUMP Push back protective caps (1). Unscrew nuts (2 and 3) and take off wires. |  |
Pinch suction hose (1) and pressure hose (2) with Special Tool 13 3 010. Loosen hose clamps (3) and pull off hoses. Note: Do not use squeeze-hose clamps on pressure hose. |  |
Unscrew bolt (1) and nuts (2). Take off fuel pump with filter. |  |
Unscrew bolt (1) and take off clamp. |  |
Loosen hose clamp (1) on fuel filter and pull off fuel hose. Remove rubber ring (2). Installation: Check direction of flow - IN and OUT are marked on filter. Do not use a squeeze-hose clamp. |  |
Loosen hose clamp (1) on fuel pump and pull off fuel hose. Pull off rubber ring (3). 2 = Code number*  * See Specifications
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