external fuel pump / wiring help

[FoxGT87]

k, i have never wired anything. it is not my forte.

my truck is an old school 5.0 with the V belts and not the serpentine system. it has a mechanical fuel pump. fuel pump is going bad, it will run then it will act stupid and loose pressure. i can not wait 2 weeks or what ever to get the same holley pump off of ebay again. so i bought an Airtex external/universal pump. i would like to put a toggle switch into my cab so that when my mech pump acts stupid i can toss some pull its way.

this is the question... how do i wire it up so that i can make this possible? im going to put the external after the mech before the carb. could i start my power source from my solenoid under the hood? how many relays? where do i put my relays at?

going to try to get this done tonight. any help is appretiated.

 

[HISSIN50]

You might have issues if you want to plumb it in-series in the fuel line. When the pump is not on, it would be an impediment to flow unless it has a bypass.

You might be able to plumb it in parallel with the mech pump.

What's the electrical draw of the pump (it might be listed on the box or in the instructions)? You probably do not need a relay but it is a good idea.

 

[FoxGT87]

how should i go about putting a bypass in? i got my all of my fuel lines going where i want them right now. and i found a place where i am going to go through the firewall for all of my wires. got to go get some 14 gauge wire, a relay, and a switch.

i was also thinking that the pump might screw up what is already there if it is after the mechanical pump. but this is what i was told to do... sigh. would the correct place for it be before the mechanical fuel pump?

 

[jrichker]

You will need to add a relay & switch for an external low pressure electric fuel pump. Do not try to wire the fuel pump without the relay. The 15-20 amps the pump pulls will overload the circuit. This will take power away from other items on the same circuit or cause the fuse or fuse link to blow.

 

[FoxGT87]

okay i got it all wired up... there is no relay yet (that diagram confused the hell out of me, and i read it after i finished.)

as of the test run i am not running the external all the time. it is running fine w/o the pump. but i definately will turn the thing on if it starts to run stupid on me. so until my friend can come down to st.pete again from lakeland (he is usually down on the weekends) a relay isnt going in.

i am happy with my first on own wiring experience it was fun. glad it wasnt on my stang >=D