double pump instructions


Feb 10, 2003
Hey guys any of you have instuctions on how to install double pump fuel pumps?Please include hobbs switch operation.Any online instructions?
Not exactly what you want but this info might help. Here is an old post of mine:

These directions are for older kits that came with twin AC pumps like mine did. It was bought in 1995 and included the hobbs switch and all hardware. If yours is a later model and has (2) Walbro 242 or 307 pumps then you won't need to change much of anything, maybe the wiring only, but I think that is the same too.

On mine one pump was failing so I went all out and did the (2) Walbro 340 pumps. I had to make a new bracket that would hold the pumps on the bottom since the bottom of the Walbro pumps are larger and not offset like the AC pumps. I used the original ATR lower bracket to patern a new one from a piece of stainless bracket material I had around the shop.

You will need a 3/4" hole saw for the holes that the pump inlets fit thru. The top billet coupler worked great with the new pumps after one simple modification. You will need to use a snap ring pliers to remove the snap rings securing the washers inside the coupler, get a drill bit slightly larger than the Walbro pump outlets and make the holes in the washers large enough for them to fit thru.

This is easier than it sounds, trust me. Don't ya just love when someone
says "trust me"?? :)

Anyways, they were a tight fit going into the tank but it worked well. One
other thing I had to do was take a ball peen hammer and gently enlarge the
tank opening where the 2 pumps are lowered into the tank. I dented the
opening just enough to make the pumps fit down thru and not enough to
disturb the o-ring seal area. You only need to slightly enlarge two spots directly across from each other in the position that the pumps go down thru. I used an insulating boot over one pump for noise reduction, and I had to use some WD-40 on it to get the rubber to pass thru the opening. They are working
great and I turn the #2 pump on at around 20-21# of boost otherwise the
motor goes way rich. Those pumps really push the fuel!

Good luck and e-mail if you have more questions.
Found this as well:

Heavy Duty Fuel Pump Relay Wiring Instructions



To supply additional voltage to the fuel pump to ensure full pressure and volume at Wide Open Throttle. The factory setup only supplies voltage to the fuel pump from the fuse panel; which varies from 11.0-12.0 volts. By feeding the fuel pump voltage from the alternator, the voltage is raised to 13+ volts.

Parts needed:

A 20 or 30 amp relay (4 or 5 prong; Radio Shack part #275-226 works great,) 15 feet 10 or 12 gauge wire, 2 feet 16 or 18 gauge wire, in-line fuse holder with 25 or 30 amp fuse, spade connectors, test light, solder & soldering iron. All connectors should be crimped and then soldered to eliminate the possibility of a bad connection. Total parts cost should be less than $20!

Trigger circuit -
Locate a spot for mounting the relay under the hood and connect prong 85 to a ground with about 1/2 the small wire. Use the other half of the wire to connect prong 86 to the Fuel Pump Primer wire behind the alternator (Black connector/Gray wire) using a male spade connector. You can now turn the ignition to ON and you'll hear the relay kick on.
Power circuit -
With ignition OFF, use about 1 foot of the large gauge wire to connect prong 30 to the hot post of the alternator (remove black cap, loosen nut, use an eyelet connector). Splice in the in-line fuse holder to this wire for safety purposes. The remaining prong on the relay is the "Power Out" that will feed alternator voltage to the pump(s).* Run the remaining heavy gauge wire from the appropriate "Power Out" prong on the relay under the firewall and through the fame rail to the gas tank connector under the rear bumper.

The 3 wires going to the sender/pump are Black-Ground, Pink-Fuel Level Sender, and Brown/White Stripe-Fuel Pump motor (on some cars this wire may be Gray.) Cut the Brown/White Stripe wire (after the 3-wire connector by bumper) and connect the large gauge wire from the relay to the section of the Brown/White Stripe wire going to the pump. If you have multiple pumps, you need to run the wire to both of them so that both pumps see the same voltage. Pump(s) will have a louder "whine" under all conditions. Re-check fuel pressure as the additional voltage may make a big difference to your setup.

* If you have a 5 prong relay the two remaining prongs should be labeled 87 and 87a. One is the "Power Out" when relay is energized, the other supplies power when the relay is not energized. Use a test light to determine.

Scott Simpson