Fuel Pump, Pressure Regulator and Relay

L-JETRONIC: TEST CHART

FUEL PUMP, PRESSURE REGULATOR AND RELAY

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Operate:

Turn ignition on and deflect air flow meter flap by hand to nergize relays and operate fuel pump. Connect pressure gauge KDEP 1034 as described in the Component Test Instructions.

Measure:

Pressure in fuel line and function of pressure regulator.

Value:

2.2-2.6 bar.

Deviation:

No pressure buildup (pump does not start):
Pull plug from pump and measure voltage at plug contacts. If reading is 12 Volts, pump is defective. If reading is 0 Volts, check pump fuse in B+ line to relay terminal 88y. If relay is operating, then check cable from relay terminal 88d to pump. If cable is OK, relay is defective.

Pressure above or below specification:
Check fuel filter and return lines for free passage. If all fuel lines are OK, pressure regulator is defective.

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Operate:

Ignition with fuel hose removed from cold start valve and placed in a graduate. Deflect air flow meter flap by hand to operate fuel pump.

Measure:

Delivery quantity of fuel pump.

Value:

1.5-2.0 liters per minute.

Deviation:

If fuel filter and lines are free and correct delivery quantity cannot be reached, fuel pump is defective.