Wiring lift pump

[reecegze]

Hey guys how should i wire in the lift pump for my surge tank ?? should i run power straight to a relay from the battery ? and then use the existing fuel pump power as a switch to power the lifter pump ?? or is there another way you guys do it ?? i don't really wanna use power from the main efi pump .

[Jonny Rochester]

That sounds ok. Each fuel pump should have its own relay. Battery power should go to both relays. EFI fuel pump wire should be the signal to turn the relays on.

I think on a standard Toyota car, the fuel pump relay is called "circuit opening relay" and is in the dash somewhere.

[slide86]

on a 4ag ecu, its a green and red wire that pulls the relay on when the engine starts

[reecegze]

same on a 4agze loom ?

[Nikkojoe]

Yes same as gze (and most of toyotas)

As slide86 said, there is a green/red wire coming off the body harness connector of the ecu. This is the Circuit Opening Relay (COR) wire.

The COR wire earths when the engine/ecu is running. The factory COR relay has 2 inputs to latch the relay. These are both the COR wire and the start signal wire (the black white wire that goes to starter motor). The start signal wire makes the COR relay latch as the engine is cranking only, so there is fuel pumping to get the car started.

So basically you need 2 relays (if you don't have a factory COR relay)

-One has start signal as a trigger on one side, and a normal earth on the other.
-The other has ignition on one side of the relay, and earths via the COR wire to the ecu.

Both will get power from battery, and both outputs of the relays will go to fuel pump.

If you don't understand how it should be done, there is a wiring diagram of the relay on club4ag of a 4age (just look for COR). I will make a diagram later :)

[reecegze]

mmm i might need that diagram... So could i just run a wire straight from the battery to a relay for constant power. ?then use the efi pump power to switch to lifter pump ? would that work and earth ? i get what your trying to saying just hard for me to understand it.

[Nikkojoe]

Here is a diagram i made. Run both pumps off this wire, but make sure your wire can handle the current...

OR

If you are already running an COR relay, use the wire that goes to the original fuel pump as a trigger to a new seperate relay :) The new relay can be powered off the battery (add a fuse aswell).
[attachment=24912:Wiring_diagram.JPG]

[reecegze]

I would assume that i have an COR already as i got the car with an external vl pump, so i gotta use power that goes into the COR and then run it to a relay using the existing power of the fuel pump as a switch ? That make sense ? if that makes sense do i just splice into the power before it goes to the COR ?

[Nikkojoe]

You have to check if you got a COR. It will be with the ecu. Easier way is to see what happens when you turn the key. Doesn't matter if you have an external fuel pump or whatever, its a TOYOTA ecu specific external relay (one which has 2 inputs).

When you turn the key to ON/ignition, does the fuel pump sound or does it only turn on if the car is running/cranking? If it turns on before even starting the car, then you are not running a COR.

As for the new relay trigger, take it as the ouput of the COR (ie splice into the wire that goes into fuel pump as I said above).