So just doing an upgraded ground at the pump, meaning splicing an 8 Gauge ground wire to chassis at the pump, gave me about .75V more on both High and Low. The solid white wire that feeds Relay 3 to Pump should be able to handle a little more voltage/current. That's why I was thinking of my plan the way I was suggesting.

 

For an Evo 8 the wire comes out of relay 2 as Brown, then it goes into connector C-123, it then comes out as red/white into relay 3. It comes out of Relay 3 as red back into C-123, then out again as white which it stays through C-113 and D-33 all the way to the pump.

 

https://www.roadraceengineering.com/...elpumpinfo.htm

 

anyone ever try this on cz4a platform?

 

Using a Hobbs switch, you would wire it exactly the same.

 

I am terrible with electrical stuff and I need pictures to be able to understand what to do ....

from this pump hardwire write up: http://lancerregister.com/showthread.php?t=459924

Instead of the fuse coming from the battery (picture below) I use the pressure switch and instead of where it says cut the power wire going to pump I will splice it and connect to it. Other than that I can just follow the write up?

Thanks

 

Sort of, you have 30 and 87 reversed. 86 and 87 get spliced into the stock fuel pump power wire. 30 gets power from hobbs switch, which gets power from the battery. I would put the fuse in between the battery and hobbs switch.

 

I'll add a few more details.

- The diagram indicates taking 12 V power from a fuel pump relay to go to terminal 86. Taking power from a "fuel pump relay" is a bit of a vague statement because there are three relays associated with fuel pump operation, and they all have different conditions when they are active. I would take it from "ON" ignition power or from "ACC" power from the fuse panel under the dash. It would also be fine to take directly from the battery. Battery would be easy because the automotive relay and Hobbs switch are easiest to install in the engine compartment.

- The Hobbs switch should be connected to terminal 85. Terminal 86 should go to ground. This is the switching signal circuit. Its necessary to use terminal 85 for the positive terminal because some relays may have a flyback diode, and if 85 and 86 are reversed, then it creates a short circuit.

- I want to clarify that "splice" into the fuel pump power wire coming off terminal 87 means to merge this additional power wire with the OEM fuel pump power wire. Do not cut the OEM fuel pump power wire. This new power source does not replace. Instead, it augments. Perform this merge in the factory wire harness at the point where the OEM harness connects to the fuel pump carrier (the white thing that holds the fuel pump). If you use a crimp splice, be sure that its up to the job of carrying up to 20 A of power. Otherwise, do a solder splice.

 

You can use a keyed source, or the stock fuel pump wire for the coil of the relay.


I also have it set up to where the hobbs switch controls the relay ground. My battery is in the trunk, so that means I only have one wire going to the front of the car.

 

I was about to do this rewire with the Hobbs switch, then just bought a Link ECU. I then realised the ECU could trigger the relay for full voltage instead of the Hobbs switch based on parameters I set.

 

Yup, standalones are nice lol.


I actually have my car wired so that the stock hi voltage relay triggers the "supplemental" power relay. It ended up being way more complicated than the hobbs switch.

 

Yea, its not even installed yet and I'm finding all sorts of cool things I can do with it. The Link plug in for the Evo 4-8 are discounted until the end of the month.

 

I've just been looking at cable to do this, and the best I've found is to actually buy an amp wiring kit, which has the right lengths of cable in them and are cheaper than just buying the cable on its own. They have 8 gauge cable in them though, but I would guess that would be fine.

 

You just buy STM's rewire kit, and use it appropriately for this set up.

 

I've got an STM kit coming.

I've been looking at my ecu wiring for fitting my Link ecu and I see pin 39 is for Fuel pump speed, which seems to be the same as the Evo 8. Does anyone know how this pin works and why we couldn't use it for triggering full power to the pump?