Dahl 100 Fuel Filter

[firemediceric]

For you guys with the Dahl 100 fuel filter, what does your vacuum guage at the filter read?

I just installed the unit and it is currently reading -11. What should I expect when the filter becomes restricted enough to slow flow to the pump?

 

[roosterdiesel]

-11 what? " hg or kPa?


I don't like to have more than 8-10 inches of mercury restriction. Looks like the vegetable oil is too thick for the 2 micron filter.

 

[firemediceric]

No veg oil in it, for the moment. I've run two tanks of straight #2 diesel in it to help clean out the tank before I do the Harpoon and Hutch mods, so the veg is not a factor right now. The fuel in the filter bowl is clear with no debris of any kind in it. I really don't think it's a fuel issue.

I am using this guage:
http://www.dieselsite.com/index.asp?PageAction=VIEWPROD&ProdID=168

 

[firemediceric]

I removed the filter from the fuel line and I read only -8, so it's definitly the filter causing the restriction-mad

 

[roosterdiesel]

You removed the element from the Dahl housing or removed the whole Dahl unit from the system?


Either way, 8in Hg is too much for the pump. Being on #2 with that much restriction I believe the screens in your mixing chamber in the tank are plugged.

 

[firemediceric]

Update

I removed the entire filter unit from the equation and had just straight fuel line. It was still reading -8-mad

I then blew compressed air through the fuel line and into the tank, thinking that the strainer in the tank may be some what obstructed.

I then hooked the Dahl back up and cranked up the truck. Where I was reading -11 with that configuration, I am now reading -8. So things have improved, but are still not great

I guess I need to be making plans to drop the tank and do the Hutch mod.

Anybody close want to give me a hand?

 

[roosterdiesel]

What's the reading with the engine not running just to rule out a bad gauge? Should be zero.

 

[firemediceric]

And Zero it is...

 

[roosterdiesel]

Did Bob's install kit come with hose to go from tank pickup to the Dahl? Only other thing I can think of is that the hose is kinked or pinched somewhere.

 

[firemediceric]

No, it did not. It came with enough hose to go from the steel fuel line to the filter and from the filter to the pump.

It's looking like this is a problem that was there before I got the filter, I just didn't realize it because I did not have a guage. I certainly cannot put any blame on Bob

I had someone suggest, even before I was aware of this problem, that I should run some 3/8" fuel hose from the tank to the filter instead of using the stock steel fuel line. They told me the fuel will flow a lot better that way as oppossed to the pump trying to pull it through a "narrow steel straw." Does his suggestion sound reasonable to you?

I think I'm going to have to find the time and the courage to try and drop the tank, which is 3/4 full of fuel right now , and at the least clean off the strainer. Maybe even remove it? If I get that far, I think I'll run the 3/8" hose instead of the metal fuel line.

Do you think I'm on the right track?