Topic: Wiring electric fuel pump

[hunmetal]

Hey guys, im switching to an electric fuel pump and ive got everything installed and hooked up except power to the pump.  What is the best place to draw power from? Does it really matter where you take it from? Im assuming under the dash after the fuse box, but I don't know how many amps my Purolator 3-5psi pump draws.  I was thinking of taking it off the cig lighter but I use that to charge my phone when im out listening to music on the trail.  Could the cig lighter handle running the fuel pump and being used as a power supply? Also ive head if u run an electric pump u should have a kill switch linked to the oil pressure in case of a rollover, where can I get one of those?  Thanks  in

[tyes]

there is a yellow plug that comes from your engine wiring harnes to your body harness. in the middle of that plug there is a big black wire. that black wire runs from your ignition switch. when you switch ignition to click 1, turn it on and its 12v you can tap that wire. I would suggest adding a relay while you at it...

[emsvitil]

Add a relay with a dedicated fuse before the relay.

Then any ignition sourced wire can trigger the relay.

[hunmetal [OP]]

Hmm... I looked for that yellow connector, are you talking about the big plug on the bottom side of the steering column?  That connector is black on my truck(85 standard cab long bed) and there is no black wire. So I guess my question is; where does the engine wiring harness connect to the body harness? Sry for the stupid questions ive never wired anything before. 

[Rocksurfer]

I wouldn't use just any old ignition sourced wire, some of those wires are emission control wires and tapping into one of those will trigger your check engine light. People make this mistake all the time usually when installing a stereo. Make sure you tap into a dedicated power source and not one for vehicle functions. Just because a wire has voltage doesn't mean it is usable for other purposes. If you are going to tap in to any old wire to trigger the relay you might as well tap into the lighter and I wouldn't suggest that either.

[hunmetal [OP]]

I went down to my local auto parts store (not a chain store) and they sold me a relay and told me how to install it, pretty easy.  But, im still trying to figure out where to draw the power from to actuate the relay.  I think rocksurfer's advice sounds good, I don't want to use some accessory to power the fuel pump and as soon as this truck is running im gonna have to wire in the stereo so I might as well learn to do it right. If Im using a relay with a fuse I should be able to draw power directly from the ignition switch right?  A buddy of mine told me that he just pulled the fuse for his dome light (which wasn't working) and stuck the +wire for his fuel pump into the socket and crammed the fuse back in and it works fine. Thats not really what I want to do though, I hate rigging up half assed redneck crap so im trying to do it right. Thanks for the advice so far and I would appreciate anymore anyone else has to offer.

[Snowtoy]

I would use a keyed source in the engine compartment, it will make it easier to get to if you have to. 

Use the keyed source to trigger the relay, and fuse both the trigger wire and the main power lead to the relay.  Fusing the trigger will protect whatever keyed source you use if you have issues with the relay, either when wiring it up or later. 

You should pick up a couple more relays as spares.

[Rocksurfer]

I agree with Snowtoy, what I do is tape two relays together, wire one and leave the second relay ready to be swapped without having to do anything but unplug one relay and plug into the next. This way you always know where the spare one is.

I've also done this with spare ignition computers/injector systems, I just tape them back to back and then reinstall them together. Of course I've never had to actually switch one out.

[tyes]

Hmm... I looked for that yellow connector, are you talking about the big plug on the bottom side of the steering column?  That connector is black on my truck(85 standard cab long bed) and there is no black wire. So I guess my question is; where does the engine wiring harness connect to the body harness? Sry for the stupid questions ive never wired anything before. 

sorry, should have mention the yellow connectors is by the ECU side not the driver side. Follow the ecu plugs up to the engine wiring harness, then you will see 2 yellow plugs. 1 of those plugs has big fat black wire. That is the wire that is hot when ignition is on. Above in that area you will find the COR right above which the blue wire is the fuel pump wire.. I think.. from there, tap and tap. and your done..

that black connector is your ignition plug and yes you can tap it from there too. i personally like it by the COR since you dont have to drag wire through everything. I have alarm, back up battery, kill switch, CB radio, ARB x2, Winch, KC lite, Reverse lite switch, interior light switches, and many more electrical items. I hate using the same source more than twice.. if you get the FSM and read the wiring diagrams you can find them easly throughout the entire truck. and again BTW, add a relay...

[hunmetal [OP]]

Great advice, thanks everybody.  I got everything I need, relay, inline fuses, and all the wiring.  Thanks for clarifying Tyes, I should mention this is for an electric fuel pump for a carb.  So I don't have an ECU, but today I'm going to look under the passenger side kick panel and see what is in the ECU's place. I like the idea of drawing it from under the hood, and I'm going to install two relays so the back up is right there, good idea.  I think ill take the power right from the ignition switch and run a wire (nicely tucked away under the dash) to the engine compartment and mount the relays there so they're easy to switch.  Thanks for all the advice.  I cant wait to get it running! this fuel pump was the last piece of the puzzle.