HOW TO: run the fuel pump for carb conversions, the easy solution! Options

[SirAndy]

Back by popular demand, Sir Andy's "HOW TO" series presents:

HOW TO: Run the fuel pump for carb conversions

There are numerous tech. articles out there that cover this issue.
When you switch from the stock FI to carburetors, you have to install a low pressure carb fuel-pump.
But, since the FI fuel pump is controlled by the FI brain, removing the brain means the wires to the fuel pump won't give you 12V ...

There are a lot of "band-aid" solutions out there, some people remove the pump relay and add a jumper there, others even run the pump off the coil!
While all those solutions work (more or less) they all lack one thing, you're now running the pump without a relay! (and in case of the coil, without fuse as well)

The best (and also easiest!) solution is to trick the relayboard into believing that the FI-Brain is still connected ...

And it's as simple as connecting one wire from the 4-prong FI connector to ground.
You keep the stock fuel pump relay and fuse and you use the stock wires to power the new fuel pump.
Below you'll see 2 pictures showing how to attach the wire. on the pump side, simple make 2 more extension wires with "male" connectors on one end and plug them into the stock (roundish) plug for the stock fuel pump.
No need to hack into the original harness!!!

This install is clean and simple! (and cheap!)

In the pics below the thick red wired replaces the FI-Brain ...
(IMG:style_emoticons/default/smash.gif) Andy

(IMG:http://www.914world.com/bbs2/uploads/post-11-1109378319.jpg)

(IMG:http://www.914world.com/bbs2/uploads/post-11-1109378417.jpg)

[anderssj]

Another "twist" to this approach . . . .

Because the pump will run as long as the key is in the "on" position, I wired a fuel pump inertial switch (from a Ford (IMG:style_emoticons/default/dry.gif) ) into the wire running from the 4-prong FI connector to ground (the "red" wire in Andy's pictures). That way if the car is in an accident, the ground is "interrupted" and the fuel pump stops (NOTE: this is a little different from Ford's approach, which puts the switch on the hot side of the pump instead of the ground).

Here's a picture of the switch:



The switch costs 25-30 new at your FLAPS; I got a couple of used ones at the local pick-n-pull for a couple of bucks each.

These switches have been known to go bad once in a while, but mine has been good for a couple of years.

Here's a link to a site that provides some good info on the switch:

http://www.therangerstation.com/tech_libra...rtiaSwitch.html

Instructions for installing the Smart Racing Products (SRP) version of the switch are here:

http://www.smartracingproducts.com/pdfdocs...fuelshutoff.pdf

My switch is currently mounted near the ground post just forward of the relay board cover. I'm thinking of putting it in the + side like Ford did--and as recommended in the SRP instructions. Then I should be able to mount the switch somewhere in the passenger footwell.

Hope this helps!