Fuel filter light on again

[dave1shere]

I don't think my fuel is too thick I make my own biodiesel and always tested it. I have been making it for about three years now and running it in my old Mercedes. As far as the truck, I always keep the biodiesel in the front tank and usually have regular diesel in the rear tank. Only because I use the truck so rarely that I want to keep diesel fuel in the return lines when not in use. So I always try to purge back to diesel before storing the truck for any length of time. the funny thing is, this problem began when I switched to the rear tank when I was running low on biodiesel. I guess that's where I need to start looking is in the rear tank. I know I have not changed those lines, because I was only running diesel fuel. I change the ones on the front tank the line, running up to the fuel filter lines, on the electric fuel pump and the tank switching valve. I had removed the mechanical fuel pump and put an electric one on long ago. I like the idea of being able to use the ignition key to purge out the fuel filter. well I'll keep everyone informed on what I find.

 

[EMD_DRIVER]

One thing you might check, is that your fuel pump is pumping enough fuel. If it's not pumping enough fuel, a vacuum will be created by the IP trying to do all the work.

 

[dave1shere]

I hook up a fuel pressure gauge, and it showed I had 7 psi. I should've taken the hose and held it down in a jar to see if I was getting any bubbles. I'll probably do that today thanks for the tip.