Wiring meth problem

[Andy]

So I have been trying to hook up my meth to control through the fps.  I have my relay wired to a snow performance pump, the relay is all hooked up right.  I know the fps ground is the wire to use and it has to go to 85 on the relay.  But for some reason I checked voltage in it and it reads 12v., with key on and off.  I checked all 4 wires coming from the fps plug and only the black wire has power.  All three other wires are grounded, I checked using a ohms meter....  Is there a short?  What is going on here I am trying to hook this up before Sat. I am going to be dynoing and tuning the car.  Thanks

[hakcenter]

you using a common fuel relay ?


I don't think you really need a relay... I'd just wire the ground to the pumps ground, unless its over 10amps ?

If you want to use the relay, 85 to fps ground, 86 constant power, I think you know how the switch above works lol no brainer there.


Just make sure your fps rules aren't being triggered in the current setup ? I'd make the trigger >5000rpm upload turn car off, turn key back on and check.

If your getting current through it still... you may have a short...

[John_H]

+1

no relay needed, tho I use one too.

its the red wire that is stupidly used for the ECU switched ground.

if thats not sending a ground(test it on its own with a test light, volt meter or even ohm meter)when your trigger conditions are met, there is a short, but thats really unlikely unless your car is a real mess.

[Andy]

The red wire is grounded all the time.  The black wire has constant 12v.   My relay is wired as you said, but the ground is always grounded and not a switched ground , therefore my pump is always active.  I tryed testing it to see if it would stop being grounded when I activated the FPs commands but it did nothing.  My harness is barley touched so I find it hard to belive it shorted.     But I guess its possible.  Anyway I wired in the supplied map sensor relay thingy snow performance provided with the kit and it comes on at 15 psi.  I have a 91 harness I am going to clean up and toss in this winter anyway so I will just leave it the way it is.   Thanks for the replys.

-Andy

[hakcenter]

The red wire is grounded all the time.  The black wire has constant 12v.   My relay is wired as you said, but the ground is always grounded and not a switched ground , therefore my pump is always active.  I tryed testing it to see if it would stop being grounded when I activated the FPs commands but it did nothing.  My harness is barley touched so I find it hard to belive it shorted.     But I guess its possible.  Anyway I wired in the supplied map sensor relay thingy snow performance provided with the kit and it comes on at 15 psi.  I have a 91 harness I am going to clean up and toss in this winter anyway so I will just leave it the way it is.   Thanks for the replys.

-Andy

Grounded all the time including when the key is off ?

Id chase that short.

[blktalon3]

So would it be: 85 to fps ground
                         87 to the pump
                         30 and 86 to fused 12v(batt)
Is this right?  I don't quite understand how relays work.
Thanks

you using a common fuel relay ?


I don't think you really need a relay... I'd just wire the ground to the pumps ground, unless its over 10amps ?

If you want to use the relay, 85 to fps ground, 86 constant power, I think you know how the switch above works lol no brainer there.


Just make sure your fps rules aren't being triggered in the current setup ? I'd make the trigger >5000rpm upload turn car off, turn key back on and check.

If your getting current through it still... you may have a short...

[hakcenter]

85 -> FPS ground
86 -> Battery (no fuse needed this relay uses zero power)

30 -> pump
87 -> Fused Battery

Pump ground to frame or any other adequate ground.

Old post! lol.

[blktalon3]

Sweet