Where is best source (12v) for fuel pump?

[BrianL1987]

What is best source for switched 12v for electric fuel pump? Mine was connected to coil but, robbed power at high rpm causing car to "cut-out". Now I have connected to battery with manual switch under dash (pain in but). I'm considering going back to mechanical pump. Is there a good power source for pump that is ignition switched?

[Zed Head]

The wiring diagram in the FSM shows that switched wiring should exist back by the gas tank for an electric fuel pump. Have you looked to see if it's still there? It shows a wire running to a 20 amp in-line fuse, located by the fuse box.

[BrianL1987]

I used that wire on 1st attempt but, it drew too much power from coil & caused car to "cut-out" at higher rpms. Are you able to see in manual which accessories are shared on that fuse (A/C?)?

[Zed Head]

I'm not sure why you think that wire is on the same circuit as the coil. The diagram shows it as its own switched ignition circuit, designed to run the fuel pump.

Also, I believe that if the pump is wired in parallel with the coil, which it would have to be unless you spliced in to the power wire to the coil and wired the pump in series (doubtful, you would have the pump - running to coil +, or coil - supplying power to pump + [your coil would see power all the time and would probably get hot, and your pump would not work well]), there should not be excess current draw to stop the coil from charging fully. It's not really clear what your "cutting out" problem is about. If you have a wire from coil + to the pump, that is a parallel circuit and shouldn't be a problem. Is that where your wire is currently (no pun intended), from coil +?

Here's a link to the FSM. Page 4 and 5 in Body Electrical show the wiring you're concerned with - http://www.xenons30.com/reference.html

[BrianL1987]

Thanks Zed, I think I can figure out now. The previous owner (I think ) tampered with some of wiring.

[jmortensen]

I ran my pump off of the wires by the tank. Pump ran slow and sped up as revs came up. This might be one of those things that would be better served by a relayed power source.

In fact, I just set my new pump and electrical system up with relayed power, or rather Dave Irwin did, as I can't wire a lamp successfully...

[esmit208]

Project 6/70 had the electric pump circuit but I don't remember seeing it on Project 3/72 when i pulled the harness out a few months ag. I will check it thoroughly during re-installation.

[jmortensen]

They all have it, I'm pretty sure. The wires are taped up in the harness near the fuel sender wires.

[Travel'n Man]

Jon -

Do you think 72 and before had the wiring bunded back there? I'm stepping up to electric fuel pump and regulator - any tips for install or brands?