imloggedin

how are you guys hooking up your fuel pumps with ms? i only saw like 1 thread on it in search, id like to run new wires but i dunno what relays everyones using and whatnot. i can use the test connector at first but like i said id like to run new wire soon after.

what are you guys doing?

quasar

keep in mind the wire comming from ms is the relay coil ground. Meaning you are going to have the 12V power comming to one side of the coil and the ground comming from the ms unit. I used an off the shelf standard brand name part number RY116. on the contact side you will have 12V power come in and 12V power go out to the pump, use chassis ground to the pump. Take the left hand carpet out and behind the speaker tower is a plug with 4 wires in it. The power sire comming from the pump motor in a S4 is black with white tracer. I think it changes from the plug to the cars harness. If need be take your pump out and just look.

imloggedin

where are u pulling the ignition switch 12v to the relay?

quasar

You can take it from the fuse box. What I did was the main power wire going to the larger fuses under the hood I jumped from that to about 4 inches away and got one of the pepboys 4 bank fuse blocks, this is my fuel pump relay, fan relay, injectors 1 and 2. You can use the same power going to the coil and the contact side. If the fuse blows you'll know for sure what is going on. I went to the junkyard for my electric fan and got a sweet deal on a fan from a late 90's ford taurus. Fits real nice but draws 105 amps to start and 40 amps to run, so my fan circuit is beefed up quite a bit. I dont share the same power source to the coil because of the load at start up. If you use an electric fan dont forget to use a diod in the circuit.

quasar

I'm not, it is powered up all the time. They recomend using a relay for this but I dont see a problem as long as you have the right fuse in line. I use 5 amp fuse. if the wire gets cut into the fuse will blow before my 12 gauge wire gets hot. 14 gauge is good for 15 amps, 12 gauge is good for 20 amps, 10 gauge is good for 30 amps. So that little fuse in my engine bay wil pop way befor I get in trouble, and the way i look at it if that pops your engine wont run much longer anyway, not like your going to be driving for a while with bad fuses.

But for the safest way go to your factory harness to the ecm and find a wire that turns on with the kay, use that for your relay.