This is Cowboy Bob's dual pump project. Although this is far from my original goal, I am happy with the result. The original plan was to have a fail safe circuit and 2 Walbro pumps. If one failed, the other would take over automatically. This proved to be too expensive for my budget and the electronics to accomplish this were a little more difficult than what I first thought. My original plan was to dump the in-tank pump but due to my project going over budget very quickly, I used the in-tank pump as the backup pump and an toggle switch to select which of the 2 pumps to use.

To start off, I had to remove the gas tank instead of the bed. #1 because of the 90 gallon tank in the bed, and #2 because of the hide-a-ball hitch in the bed.

 

Next I had to put in some way for the Walbro pump to get fuel out of the tank. Since the in-tank pump had replaced the old sending unit, I had to fabricate a pickup tube. Since I used AN fittings, I drilled a hole in the top of the tank right next to the in-tank pump and placed a bulkhead fitting in the tank.

On the other end, I put my fabricated pickup tube. I made it from an AN fitting and 3/8" hard-line. I connected my fabricated pickup tube to the other end of the bulkhead fitting inside the tank.

 

Next I fabricated a mounting bracket for the Walbro pump.

 

With the tank out I was able to fabricate a 3/8" hard line for the second pump. I place an AN fitting on each end and the check valve on the end going toward the engine.

I ran this along the frame rail underneath the original fuel line that runs from the in-tank pump. You can see in the picture below, the tank removed, both fuel lines with the check valves up by the transfer case.

 

This was my first attempt, but I soon realized that I was going to spend more time and money on this project. The fuel PSI was too high!!! over 40 PSI! That is as high as my gauge goes!

So I had to purchase a pressure regulator and run a return line back to the tank. I installed the regulator underneath the check valves that you see in the above picture. I was running out of room to mount stuff, so I had to remove the skid plate and cross member to have enough room to work.

I decided to run the return line off of the regulator, inside the frame rail and up to the 3/4" vent line on the fuel tank. This allowed me to keep from having to drop the tank again and drill another hole in it.

 

Next I wired the pump and connected it to the bulkhead fitting I had drilled in the top of the fuel tank. I placed an in-line filter in front of the pump so that it would keep any trash from entering the pump.

Now that everything is mounted and ready to go, I turned on the pump and checked for leaks. Once I had it ready to go, I started it up and looky, looky, 16 PSI at idle. I've never seen a reading that high with my in-tank pump. In fact, I've never seen a 2 digit PSI reading with the in-tank pump.

Next I flipped over to the stock in-tank pump and noticed something was wrong. I was only getting 4 PSI at idle, instead of my normal 8 PSI. I checked for leaks and there were none. Then I realized that I had put the pressure regulator in front of the check valve. The fuel from the in-tank pump was running backwards through the regulator and through the return line and back into the tank. Since I had no AN fittings to move the check valve, I had to leave it this way for the time being. Besides I don't plan on using the in-tank pump unless it is an emergency. This brings me to may next point.

Don't use AN fittings unless you have a good source for them, or you have plenty of patience. There are no stores anywhere close to me that sell them. Most of the local yocals didn't even know what they were when I called to see if they sold them. I had to draw out on a piece of paper about 10 times what I wanted to do and still didn't get the right fittings the first go around. Also, if I break down in the middle of no where, and there isn't a speed shop or race track around, I probably won't be buying any AN fittings from a local store. The closest place to me that sells them is 1 hour and 20 minutes drive.

I am extremely happy with my setup. I get 2 digit PSI readings even if I put the pedal to the floor. I did find out the hard way that my pickup tube does not suck diesel off of the bottom of the tank as well as the stock sending unit. At 1/8" of a tank the engine stopped. The gauge was correct, just the tube didn't go all the way to the bottom. So I am going to keep my eyes on Ebay for a while or try to find stock sending unit at a junk yard. When I do find one, I will drop the tank again to install it, and run hard line for the return off of the regulator. I will also drill another hole and place a bulkhead fitting in the tank for the return line. I also plan on moving the regulator behind the check valve for backup pump, but will need some more AN fittings to accomplish this. So I will only be using the Walbro pump for now. If I do break down with a broken pump, it is much easier to change the Walbro, than the in-tank pump. In fact, I could probably change it out in 15 minutes on the side of the road. Can't do that with the in-tank pump.

The regulator also has a vacuum line that will increase the fuel psi as the rpms build on the engine. I am going to see if I can figure out a way to use this as well.
 
Click Here For Part 2 of This Project