TheSamba.com :: View topic - How to hook up an electric fuel pump with no problems

Sat Nov 24, 2007 9:41 am

My 66 came with an electric fuel pump already installed in it. Yesterday the hot wire got to hot and started to burn. Luckily, I am putting in a new interior & The battery was exposed, so I was able to pull off the pos. cable. The toggle switch, which was a 30 amp, shorted out. The hot wire was hooked up to the coil wire & previously had no problem. My question is, what is the correct way to hook up the electric fuel pump & what size wire should I use. I have a new 30 & 50 amp toggle switch & a new inline fuse.

Sat Nov 24, 2007 2:53 pm

The correct installation requires a relay and a fuse or circuit breaker. The lack of a fuse means that in the event of a short circuit, the wire becomes the fuse and commences to melting and/ or burning as you have experienced. The purpose of the relay is to keep the current needed to power the fuel pump fron flowing continuosly through the toggle switch, thereby melting and/ or burning the switch over time. I use a small general purpose relay commonly available at any Harley type motorcycle shop, it is sold as a starter relay and is around $10. You could run a 10 amp fuse in the circuit but I have successfully run a 7.5 amp fuse on my fuel pump for years without need for replacement. 14 gauge wire would be a good bet if it's a fairly long run, my wire length is short and have been running 16 gauge successfully for years, but bigger is always better in the wiring world.

Sat Nov 24, 2007 3:21 pm

How about this..use the ignition hot to power the relay. Attach your fuse to the B+ at the generator. That way you don't need no steenkin wiring or switch. When you turn on the ignition, there it is!

Sat Nov 24, 2007 5:33 pm

http://www.nls.net/mp/volks/schem/pump.gif This is how I understand it.
The purpose of the relay is a safety factor. Powering relay from idiot light circuit means in event of accident, engine will stop, removing power to the relay, cutting power to fuel pump. With pump powered by coil or ignition switch, pump will continue to work unless ignition is turned off. The momentary or pushbutton switch provides power to run pump to fill carb if vehicle has been sitting or stored for a long time and lost pressure. Purely optional, just will shorten time to start.

Sat Nov 24, 2007 5:49 pm

the best place for your fuel pump is closest to the tank.an electric pump should never be near the engine,in case of an accident.all you have to do is put an inline fuse to the ignition and run the wire to the fuel pump the inline wil prevent overload.you can also do it with a circuit breaker which is over kill but it will save you an fuses in case you happend to get another short.and remenber to always run all you electrical wires thru a grommet or else your asking for trouble.

Sat Nov 24, 2007 6:51 pm

Here's where I mounted mine.......It's wired to the panel with a fuse. It's the black thing that says FACET.

Sat Nov 24, 2007 8:07 pm

Another good thing to do is go to the junk yard and find an "emergency fuel cutoff switch" from any late model 1990's and up Mustang, Focus, Explorer.

They come in handy as they are designed to shut off in the event of a hard knock (accident/curb at 30MPH) or rollover. That one little device will end all worries of "What happens if?".

Most of the time you can find them in the truck/rear compartment area on the drivers side behind the side panel attached to a bracket on the body.

Runs about $5 to $10 bucks at the junkyard.

Cheap investment. I use that on all my cars that have modified fuel systems.

Sun Nov 25, 2007 12:20 am

eweave wrote: Another good thing to do is go to the junk yard and find an "emergency fuel cutoff switch" from any late model 1990's and up Mustang, Focus, Explorer.

They come in handy as they are designed to shut off in the event of a hard knock (accident/curb at 30MPH) or rollover. That one little device will end all worries of "What happens if?".

Most of the time you can find them in the truck/rear compartment area on the drivers side behind the side panel attached to a bracket on the body.

Runs about $5 to $10 bucks at the junkyard.

Cheap investment. I use that on all my cars that have modified fuel systems. If you've got a friend {or enemy} with a mid 90's Crown Vic you can give it a thump on the quarter above the left rear wheel and it'll trip this switch and the car won't start! It'll take a non car guy weeks to figure out! :lol:

Sun Nov 25, 2007 7:05 am

I've run nothing but stock fuel pumps since I inherited my first bug in 1969. If it ain't broke, don't fix it. The stocker unit pumps gas for my Solex 30 Pict in my 1970 with a 1600 and it feeds the dual 48 IDA's on my 2213 tire burner as well. I've never had any problems with fuel pressure that would require an electric pump.