Quick question about wiring my Weldon pump to XFI

[d0n_3d]

I have a FAST XFI. On the harness there is a fuel pump wire that is supposed to be connected to the "negative" side of a relay used to energize the pump. My question is...where do I wire the other side of the relay? Do I go to IGN in the fuse box or do I just ground it? I already have the two power wires of the relay hooked up. Thanks.

Addition: Basically I want to know is the FAST fuel pump wire supplying the 12v to the relay or do I get the 12V from the fusebox/wire harness in trunk?

 

[dizzlesturbo6]

the f.a.s.t. box will supply the ground to the relay and the ignition(12v key on) can be sourced from either the trunk(old fuel pump hot) or the fuse panel. are you running a fuel pump controller?

 

[d0n_3d]

no pump controller needed on a 2015A pump

so the FAST wire supplies the ground for the relay...so I need to get a 12v source wire from either the fuse box or someone said I could tap off the tan/white wire in the trunk for a 12v source which I'll probably just do that...ok thanks

 

[d0n_3d]

OK I got everything wired up and I went to go try and see if the pump would activate and I'm not getting it to come on. I tested the tan/white wire in the trunk which is supplying my relay with 12v and its only showing me .40 V with the key on. I checked all my fuses and they are good. I'm getting 12v on my power wire going from the battery to the relay but nothing anywhere else. Here's how I have the relay wired:

1. battery to relay with 30 amp inline fuse
2. relay to positive on fuel pump
3. negative on pump to ground
4. FP pin A wire from FAST harness to kill switch, and then to negative side of relay
5. tapped into tan/white wire in trunk and wired to positive 12v switch side of relay

Did I miss something here? I have the default program loaded on the FAST ECU right now and the fuel pump prime time is 4 seconds. It's doing nothing and the red light on the pump itself isn't lit.

 

[Chevota]

http://fuelairspark.com/Instructions/XFI_Schematic_Option_Harness.pdf

Scott Wile

 

[dizzlesturbo6]

i think the problem with using the tan/white wire is that it is controlled through the stock ecm. you no longer have the stock computer so that wire is dead no?

try a 12v trigger out of the fuse box(or use a power probe if you have one) to the side you have the tan/white wire hooked up to and try and have a friend do the key on. you should then get your 4 second prime.

 

[d0n_3d]

http://fuelairspark.com/Instructions/XFI_Schematic_Option_Harness.pdf

Scott Wile

Thanks I got it wired this way. I'm just trying to figure out why I am not getting 12v at the tan/white wire in the trunk. I'm not even getting 12V at the fuse box where this wire plugs into (brown solid copper wire).

 

[d0n_3d]

i think the problem with using the tan/white wire is that it is controlled through the stock ecm. you no longert have the stock computer so that wire is dead no?

try a 12v trigger out of the fuse box to the side you have the tan/white wire hooked up to and try and have a friend do the key on. you should then get your 4 second prime.

that's probably it...the stock ECM is gone. That's probably why I'm not getting 12v at the fuse box at that wire because it is tied into the ECM wiring. I'll get another 12v source and see what I get.

 

[dizzlesturbo6]

yessir. let me know tomorrow how it goes.

 

[Otto J]

that's probably it...the stock ECM is gone. That's probably why I'm not getting 12v at the fuse box at that wire because it is tied into the ECM wiring. I'll get another 12v source and see what I get.

The Tan/White wie gets its 12 volts from the factory f/p relay on the pass fender.
Are you using a jumper harness? or stand alone?
The Caspers jumper should trigger the stock f/p relay.
If this is how you ave it ground the relay to the chassis.
and your stck fuel pump t/w wire should turn your weldon pump relay.

If you testing the t/w wire,and it is hooked the way i explained,It
will only have power for the number of seconds your XFI is set to trigger
in the global parameters

 

[d0n_3d]

I got the pump to prime. It was the tan/white wire that was dead. The relay wasn't getting 12v like I thought. Thanks for the help guys. Now onto something more complicated, running new brake lines!

 

[dizzlesturbo6]

now hurry up. i want to hear that monster run.

 

[d0n_3d]

The Tan/White wie gets its 12 volts from the factory f/p relay on the pass fender.

Well you just nailed it right on the button. I don't have the factory fuel pump relay anymore. This is a complete overhaul project. New standalone FAST harness. There's pretty much nothing factory in the engine bay.