does it do the same thing on both tanks?...

 

May need to look for blockage in the inlet line ...

 

thats what I was thinking! Leaf floating around in the tank so some dumb thing like that.

 

I will check it out. What happened was I was driving on WVO on the freeway and it felt like I had a plug fuel filter. I switched back to my biodiesel tank and drove about another 5 miles before it died. I pulled the fuel filter and there it was about half full of fuel. I could see fuel in the valley. When the truck was loaded on the tow truck fuel leaked out. I know that the first fuel pump failed. I cut apart the first pump and you can see the fuel below the diaphragm.

I installed a new carter pump and it builds 50 psig. The gauge was steady. No bounce to the gauge at all. When I drove it on biodiesel it was missing. It never ran good with the second pump. I just got it into the driveway and there was no pressure on the gauge. I switched out my 100 psig gauge for a 30 hg to 60 psig gauge. I could pull fuel from the biodiesel tank with a hand help vacuum pump. The engine would start and run for about 5 minutes. One would think that if it was a fuel line blockage that the little vacuum pump I used would just be pulling vacuum and not fill up the filter housing. The lift pump is nothing but a vacuum pump. I never switched over to WVO on this pump.

When I would start the engine by pulling fuel into the filter housing and run the engine the pressure on the compound gauge would go to 10 hg and the engine would die.

I pulled the new pump and installed another pump. The pressure was 45 to 55 and the think ran great. I was running on WVO when it lost power and I switched to my biodiesel tank. The question is how could I have a blockage in both tanks?

Thanks for the help. I am pulling my hair out on this one.

By the way the old pump lasted about 4 years and I did the replacement my self with help from this site.

 

The block age could be in the lines from the selector valve or in the valve itself.

 

I pulled fuel using a vacuum pump in to the fuel filter and it started up. Fuel pressure 55 psig. I did a test drive and it's running good. I am thinking that the WVO tank has some junk in it and when I switch to the WVO tank it sucks the junk in to the fuel lines and blocks it. I need to pull the tank and see what type of build up I have had over the last 3 years.

 

I got it running! Please don’t laugh…… Here is the long story.

Go to the end if you don’t have time to read the whole thing.

First pump failed. I knew that I had some fuel in the valley for some time. Running Biodiesel and WVO I never smell fuel like you would with Diesel. Front tank is WVO, I was running on it when it felt like a clogged fuel filter I switched to the back tank. This tank has Biodiesel in it. I drove for 5 miles and the engine died. Checked fuel filter and it was empty. Change out fuel pump and start engine and run about 5 miles with it on the Biodiesel tank. It never ran right. Replaced new fuel pump and it ran like a dream. Switched to WVO and ran about 5 miles and felt loss of power and switched back to Biodiesel and the engine died. I setup a purge system for my WVO fuel filter and pulled a vacuum on the downstream side of the filter and I got only air. I am thinking fuel pickup in front tank is broken. My fuel gauge say’s I am full on the front tank. Then it came to me…… My front tank level is broken and the tank is empty and I am out of fuel. Easy test I add 5 gallons of WVO to the tanks and hookup my new vacuum purge for my filter and I pull all the air out of Racor 120T fuel filter that I use for WVO. I check the fuel gauge and it still shows full. I go for a drive and switch over to WVO and it runs like new.

The short story……
Fuel gauge stuck on full and you’re out of fuel. Your fuel pump was weak and failed completely when it sucked air. You’re second pump was bad. You’re third was good but the PSD will not run on air!
Thanks’ to all that gave me advise. I can’t believe I missed this one!

 

Gotta hate that! but at least your fixed and running again!

 

Dejavu! That happened to us on opening day at the ballpark! Truck got stuck in the middle of the out field just before the parade was about to come marching into the ball park. Obviously had no time to figure that one out so we just towed it out of the ballpark but it was the fuel Gage stuck on full with a empty tank.

 

Dohh! Don't you hate when that happens I had the same thing happen too.
Glad you got her fixed.
Maybe you should add some diesel stink to the WVO? LOL