Fuel pump wiring question.

[RomanV]

Okay.

I want to rig up my fuel pump to run continuously, to check it.

There are 5 wires attached....

1 large earth,
1 large blue wire,

1 small earth,
2 smaller wires.

I would imagine that the large earth and large blue wire are the power source for the pump, and the small earth and small wires are what control it, via a relay or something.

If I Earth the large earth, and apply 12 volts to the large blue wire, it makes whirring noises, like the pump is running. Yet no fuel comes out of the fuel line, which i have disconnected, and placed over a bucket. (In the hope that it would pump petrol out)

Now... Are the three smaller wires necessary for the operation of the pump? Does it not pump until it gets a signal from the smaller wires, or something similar?

Is my pump past its used by date?

Any help appreciated.

[RomanV]

Okay, I just found out.

The three smaller wires are for the fuel level gauge.

I could perhaps have the polarity, the wrong way around, and I'm pumping backwards.

[RomanV]

It seems that my '12v' was dodgy... getting it from another source, and it pumps away fine.

However I blew a fuse when I reversed the polarity. *doh*

[gasman]

playing with intank fuel pumps are always fun when your trying to work out why your car wont start and the wiring is dodge as hell.