TNT_Z28

ok, i need to know straight up if my fuel pump in the gas tank of my car needs a relay or not. ('87 carbed, 2 pumps factory, 1 in tank, 1 on the block.)

i removed a sh*t load of wires and 6 relays from my engine bay when i swapped carbs and distributers. one must have been the pump relay cuz when i checked it, it didnt run. i found the power wire going back to the pump in the tank, cut it, and connected it to the ignition port on the fusebox. that worked fine(fuel started flowing out of the line), but when i tryed putting a relay in between the fuse box and pump, i cant get it to work.

WTF? do i even need a relay? wouldnt it make sence to just wire it to the ignition so that when the car starts, so does the pump?

jonarotz

iTrader: (26)

Electric fuel pumps should always use a relay.

TNT_Z28

why? can you elaborate?

jonarotz

iTrader: (26)

Relays are designed to handle the high current draw. An electric fuel pump can pull quite a few amps and a relay is more capable at handling it then your ignition switch. While hooking it right to your ign. switch will work but over time your switch may fail due to the high amperage being pulled through it. I recommend installing the relay.
Half of the relay will have a low amp circuit, this is for activating the relay. The other half is the high amp side. If you need help hooking it up let me know.

TNT_Z28

i tried to hook it up and failed. ive got power going in from the ignition box, and a wire that powers the pump. there are two other blades on the relay, what to those go to?

jonarotz

iTrader: (26)

You need the following
- 12V ign power
- gnd
- batt. voltage
- pump
I am not sure what relay you are using but these are the 4 wire hookups you will need.

TNT_Z28

thanks. its just a simple relay i picked up from o'riellys. wheres a source for batt. voltage?

TNT_Z28

ok. what i did is this.

i cut the tan wire from the tank right by my clutch pedal. i then bought a simple relay from o'reillys. i mounted the relay right behind the lever that pops the hood open.

i ran a six inch wire from the ignition port in the fuse box to the relay. i connected the cut (tan) wire opposite of the ingition wire.

then i spliced into the power wire from the battery to the computer, (in my case it was an orange wire) using a Y connector. i ran a wire from there through the firewall and to a port on the relay.

then i connected a ground wire opposite of the battery power i just connected.

this seems to work fine. when i turn on the ignition, fuel starts to flow. i hope i did this right. im no expert when it comes to electronics but like i said this seems to work. ??????

travis401

iTrader: (1)

Sounds about right. A constant 12v from the battery, a ground, a 12v out to the pump, and a trigger wire from the ignition.