Vw bus fuel pump relay

110

01:29:19

Pump automatic shutoff when the engine is not turning. Signal should cime from coil- 

published 4 years ago

Frequency

4 years ago

Remember the coil puts out between 3,000 -18,000 volts.

Frequency

4 years ago

On those old engines you also need the fuel pump running in order to get enough fuel to the carburetor or carburetors to start it so the fuel pump will need to be on before you're even receiving a constant coil signal.

solex

4 years ago

The signal comes from the coil- (terminal 1 on primary side of the coil) which puts out around 30-50 Volts (have yet check it on the oscilloscope as my bus is in storage ). I'm working on a prime circuit to turn on the pump for 5-10 seconds when the ignition key is first. A 300k resistor between Vcc and pin 2 of the 555 and a 18u Capacitor between pin2 and ground should provide a 5 seconds initial high output on pin 3...

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