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g6civcx · 06-08-2006, 05:13 AM

Most of the fuel pump schematic is described in here: http://www.zilvia.net/f/showthread.p...uel+pump+relay

In electronic circuits, the relay is a device that allows a small current to control a much larger current. Take our cars for example. The ECU is a very sensitive device that uses very low current. The fuel pump on the other hand draws a lot more current.

So in order for the ECU to control fuel pump current, you need a relay. Otherwise, the ECU has to deal with the task of handling a very large current and supplying that current to the fuel pump. You don't want that large a current flowing through the ECU because it can damage the circuit board.

So the relay's job is whenever the ECU draws current, the relay sends battery power to the fuel pump. This keeps the high current off the ECU wiring and isolates the high current.

06-08-2006, 05:13 AM	#17
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5)	Most of the fuel pump schematic is described in here: http://www.zilvia.net/f/showthread.p...uel+pump+relay In electronic circuits, the relay is a device that allows a small current to control a much larger current. Take our cars for example. The ECU is a very sensitive device that uses very low current. The fuel pump on the other hand draws a lot more current. So in order for the ECU to control fuel pump current, you need a relay. Otherwise, the ECU has to deal with the task of handling a very large current and supplying that current to the fuel pump. You don't want that large a current flowing through the ECU because it can damage the circuit board. So the relay's job is whenever the ECU draws current, the relay sends battery power to the fuel pump. This keeps the high current off the ECU wiring and isolates the high current. Last edited by g6civcx; 06-08-2006 at 10:40 AM..