Air in my WVO fuel line
 

Converted my 190d, oil switches over and burns fine, but pockets of air between the aux wvo fuel tank and the wvo fuel filter keep causing the engine to stall. Tightened all the relevant hose clamps and the 12 gallon aux wvo fuel tank is 5 gallons full. Where"s the air coming from?!?!?

Engine is being starved of fuel, check for

a) blockages such as filters, pre-filters (on 190 its on the belly of the tank)

b) Pipes are too small

Ahh yes, the inevitable air leak...
One of the big issues with veg oil systems, and one that will leave you on the side of the road in short order.

Something is not tight enough or restricted, causing you to draw air into the system. I assume you have new filters on there, those will plug real fast with a poorly filtered batch of oil. What kind of fittings are you using where your hose clamps are? Are they multi-barbed, or just rubber over metal? Low quality connections will surely give you trouble. This is a likely place for a leak. Even if you would not normally draw air into the system at one of these points, if there is any kind of restriction at all, air will get sucked. You do need 3/8" id hose at a minimum. Is the oil hot and thin, or cold and thick?

How far are you moving the oil? Are you making the stock fuel pump do all the work? You might have to reconsider that...

If you just can't find your leak, temporarily running clear hose lengths in place of your fuel line can help you spot it.

air in oil
 

Thanks, I installed clear lines between the wvo filter and the valve switch and can see clearly that there is air being introduced before or at the filter. There are only 2-3 clamps between that point and the aux wvo tank, so unless the hose in that tank is above the oil level partially(I haven't tried more than 5 gallons in the 12 gallon tank) I don't know how this is happening. I've been using a vacuum pump to test it out though I think my stock pump could use an assist. I believe there are inline pumps I can buy and install...

The diesel fuel system pumps just fine. Only a problem when I switch over to Veg Oil. The conversion kit is brand spanking new, so I doubt there are any blockages. I will try filling the aux wvo tank all the way to be sure the fuel hose in it isn't above the 5 gallons that are in there(unlikely, but possible), otherwise, I'm stumped.......

Something is not tight enough or restricted, causing you to draw air into the system. I assume you have new filters on there, those will plug real fast with a poorly filtered batch of oil. What kind of fittings are you using where your hose clamps are? Are they multi-barbed, or just rubber over metal? Low quality connections will surely give you trouble. This is a likely place for a leak. Even if you would not normally draw air into the system at one of these points, if there is any kind of restriction at all, air will get sucked. You do need 3/8" id hose at a minimum. Is the oil hot and thin, or cold and thick?

I'm using a variety of metal hose clamps on the tubing...the oil might be ****, I'm not certain of the source though I know it's double filtered. The filter is brand new...I haven't been able to drive the car on veg oil yet.....