Well if you want to run just the external off of the low voltage system, then you'll wire it up just like in the wiring diagram, You will just have to make sure you splice into the factory white wire that went to your intank pump but run it to the external pump.

 

Will that affect the power the intank pump gets currently? Or is this just a signal wire?
It seems like you cut into the white wire and you also splice into it further down the wire. Will I be able to see the area to be cut and spliced both in the little lid you take off to get to the fuel pump? Or will the cut be closer to the firewall?

 

you'll want to cut the wire coming from the relay under the hood... and as per the diagram on the previous page you would run it to the wire in the pump hanger window... then that circuit instead of running to your oem pump would be redirected to your surge tank pump. this would enable dual voltage to that pump... one more additional splice would be tapped from that wire to power a relay as per the usual hardwire diagrams to power the oem pump with full battery voltage. i hope that helps... if not well **** idk

 

Where did you hear that?? I would expect quite the opposite.

 

Thanks that help clears things up a little bit. However I am curious if after cutting the wire at the firewall, it looks like i need to run a wire from the cut on the relay side to my new relay pin 85 correct?
Also by hanger window that means where I tap in will hopefully not require taking the fuel pump out of the tank as that would require running a wire into the gas tank and sealing issues... So hoping to clarify that I can just tap ontop of the hanger without taking the hanger up and out of the gas tank? Thanks!

 

No you will not pull the hanger from the tank. You already have your intank pump rewired with a relay?

 

Are both relays underhood on black plate with 2 resistors? One resistor is for injectors. Are both relays for fuel system? One relay has black plug and one has a grey plug.

 

Not sure... I bought the car and it seems to have an upgraded fuel pump but no idea how the wiring was done. I didn't see any relay when I popped the screws that hold the access panel to the top of the tank/pump. I am also waiting on an adapter for my fuel pressure sensor before i actually try this mod out just to be safe

Are there certain areas people like to put relays for aftermarket fuel pumps? Just trying to figure out where to look.

 

A great indicator of after market wiring is the random 16ish gauge wire ran directly to the battery. Also you have to splice into the pump wiring in that window so you would at least see some fishy wiring.

The 2 relays on the fire wall are for the pump if i remember. The little block on the left is theinjector resistor pack that you mod going to high z injectors. And the one on the right is the dual voltage resistor for the fuel pump. Idd place to mount them considering everything else inmy opinion.
I dont have pics of how i did it when i went back to dual voltage. But i just followed the diagram on the previous page and it worked... My car is dis assembled and i'm mid wiring tuck ad te moment so it will be a minute before i can put up pics. I might mod my friends car so i can show everyone

 

Thanks for being so helpful Joseph. I dont see anything wired directly to the battery aside from my surge tank, yet i've already done 500rwhp dynojet with my meth system... Guess i'll have to pop that lid to see if i do infact have aftermarket pump wiring.
Do most guys that run aftermarket pumps also use a relay or do they just run thicker gauge wire to the battery and rely on the factory relay?

 

I would guess that MOST people just use the factory wiring with an aftermarket pump. But still alot of people will rewire the pump for a constant 14v with a relay and thicker gauge wire.

It can work fine either way but sometimes when rewiring the pump to constant 14v will cause the pump to Overrun the stock fuel pressure regulator at idle (higher fuel pressure than normal) and to remedy you can replace the fpr with an adjustable unit or drill out the siphon in the fuel housing.

 

Even a Walbro 255 with a full voltage rewire will overrun the factory return system at idle/cruise. Most people just don't realize it or figure that running crappy at idle/cruise is the price to pay for power.

 

MrFred any word on the low/ high wire kit yet?

 

So would it be safe to say that if I can't find any wiring directly to the battery, and I cut the
white wire to run to my surge tank relay, that my intank pump wont run right?

Looks like I will have to wire both pumps to use the high/low circuit (unless my current intank works this way already)? If so how is this done? Is the white wire the (nautural open) low voltage wire or is it the high voltage for (NC)? Am I understanding wrong since there is no pin 87a utilization in that diagram?

Could I do this with just one relay for the surge tank or will I also need a second for my intank?


I would go drive the car and check with a volt meter but it's in peices atm......
One of the things I love about my car with S1's is that it sounds like a corolla at idle and light throttle, no backfires no pops no burbles no smell, no cat. I think this largely has to do with the high Z ID injectors (i could be wrong)

 

Well, I'm not sure if you would want to run the high/low circuit on both pumps at the same time as the factory resistor was probably not designed for twice the amperage of both pumps, this could lead in the resistor burning out prematurely.
Probably your best bet is to either run the walbro on a rewire so that it is wired full time high. And then use the factory low circuit with the rewired high circuit on the previous page for your inline pump.
Either that or run a hobbs switch to the inline pump.