I just finished my two tank conversion and I am having problems with the return line having a constant flow back into the oil tank. I set it up so it always returns to the oil tank so that on start up and shut down the purged oil doesn't mix in the stock tank. I was told I shouldn't have that much return flow??


I'm using a Pollak selection valve... What ever help is greatly appreciated.

check out my schematics in my pics area, theres some ideas on plumbing.
You can do a loopback return to maximize the heat in the fuel, do a straight feed/return, or make a hybrid setup with some creative fuel switching.
Personally Id go with the straight feed/return setup and move the filter to the vacuum side, losing the pre-filter/heater for the diesel side.
Id look into hydraforce switches.. they take the heat a lot better than the pollaks.
If you switch back after about 30secs with the feed first then the return, you should return a small amount of diesel into the aux tank and be safe.
mcmaster-carr sells sight glasses that work really well. You can install a couple and watch for air and fuel purge time.

Hi I just went through this a few weeks ago.....I could let you bang your head a while but I'll tell you what I did. I had originally just puled off the two short hoses between the OE fuel filter and the injection pump...and ran those through my Pollack......As I was driving around I was gaining fuel in my dino tank and losing it in my Veg tank when I had it on Veg.....I put in the big bucks and bought the hydraforce valves because I thought it was my Pollack.....same thing after that install....There is a tee in the return line that is kinda hidden and runs through the filter housing and back to the tank...I put the return line hose back on the fuel line and teed in after the line came through the filter housing on the way back to the tank.....fixed....If I had it to over again I might have stayed with the pollack.....it is kinda nice to be able to purge a little of the veg before returning it all back to the Diesel tank.

I'm not saying how much I have burned but I am very happy with the power and mileage so far on my 06.

Good luck

Frybrid has some info on the dodge conversion somewhere on their site. They have you cut the injector return off of the filter and tee it into the return on the fuel switches brass barb fitting. drill and tap 1/8 npt.
If youre going to buy the switches frybrid sells them at a decent price and offers a higher flowing model you can install on the feed side like I did.
I have two pollaks in the original boxes and a spare hydraforce valve I should put in the classifieds.

Thanks to both of you for the info. kawi600 I found that schematics on you profile. Which program did you use to make/view that I am having trouble reading it and when I blow it up it's to blurry to read. With the info on the return... I spliced in just above the tank and I was trying to set it up so it would all return to the diesel tank but I have found that it is nearly as much flow on the return as the feed to the motor so depending the way it is going I can drain the one tank to the other. I wasn't sure how much the return is supposed to be pushing through?? I also have a heat filter set up for the bio right out of the tank and the lines are pulling air I have checked over the filter element and there are no problems with it, what I'm getting at is what would be recommended in regards to in-line pumps to assist in picking up out of the bio tank.