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-   -   How to: wire your stock pump for return fuel, the easy way (http://www.focusfanatics.com/forum/showthread.php?t=315794)

disciplerocks 05-04-2013 06:12 PM

How to: wire your stock pump for return fuel, the easy way
 
I thought I'd share a bit of info that I came across while doing my motor swap. Everywhere I looked for wiring just said to run new wires back to the pump. This is what I found.

http://i19.photobucket.com/albums/b1...psf7c590a4.jpg

Take this wire here, the second black wire on the plug, and run it straight to a ground. Its the pumps ground wire and that is what the system uses to kill the pump. Therefore you get to keep the switched power, fuse, and relay. The green/orange is the power wire.

This pic is from an 04 tank. Wiring colors may be different for other years, but should be the same in position on the plug. If you are unsure, pull the pump and follow the wiring.

And if you are not using the stock pumps or tank, you can still use the power wire and keep the stock fuse and relay.

mikebontoft 05-04-2013 08:10 PM

Nice work. It's not even something I thought about yet. I guess the fuel pumps on these are PWM based on the input from the fuel rail pressure sensor? Instead of allowing the computer to control ground, you're just running the pump continuously with key-on. Nice.

1turbofocus 05-04-2013 08:30 PM

This isnt a good idea , if you noticed the wires were twisted together this means they go direct to the ECU if you have a voltage spike you will kill the fuel pump driver and ECU , THIS IS A VERY BAD IDEA

You also run the fuel pump at 100 + % all the time even at idle which is going to cause issues at the Injectors as there going to be running at a lower more unregulated pulse width and a lot more , I wouldnt do this , I tried it back in 2000 and found all kinds of issues that you are not even thinking about

Tom

mikebontoft 05-04-2013 10:31 PM

yes 100% duty. Fortunately for us, Focus computers need not apply.

What other focus applications would use a return fuel system though?

focusmaniaczx3 05-05-2013 04:16 AM

What about doing this trick with a surge tank?

Turbo Turtle 05-05-2013 07:15 AM

a surge tank is no different than running a separate fuel cell. it is just a small one that is fed by the stock fuel system

disciplerocks 05-05-2013 02:05 PM

Quote:

Originally Posted by mikebontoft (Post 4713496)
yes 100% duty. Fortunately for us, Focus computers need not apply.

This.

And how would you wire a return system with the Focus ECU? I am interested to know. If you are keeping the stock power supply, then how would that not prevent a spike?

ZXthrizzle05 05-05-2013 02:29 PM

tom uses a fuel cell.

disciplerocks 05-05-2013 04:39 PM

That doesn't explain anything

Paladin 05-05-2013 07:20 PM

this is on your v8 car i take it?


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