Hi all I have a 98 6.5 TD tht I run the odd tank of Bio fuel I make from used veggy oil. Been having problems with rough start and idle and changed out filter and in bottom of fuel bowl was a 1/2 thick almost plastic like toffee type white substance. It almost seems like plastic. Id post a picture but since this system wont go to my hard drive and I dont flicker or bucket I cant upload.

Rags

Sounds like a gum that hit me, I think it's due to old WVO. If it is, it gets through all filters and appears to settle onto upwards facing surfaces when the vehicle is at rest.

Stop using your vehicle before you face an IP rebuild. Dump all fuel including tank and wash out fuel lines with carb cleaner. I found houshold cloudy ammonia good too especially in the tank which I water blasted. You may find that the normal range of solvents won't touch it.

Rough start and idle bit of a clue where you are heading.

Toluol or toluene is a component of carb cleaner, also very effective.

Actually from memory carb cleaner is about a third each of acetone, methanol and toluol and makes a terrific cleaner solvent.

quote:

it gets through all filters and appears to settle onto upwards facing surfaces when the vehicle is at rest.

That is likely a mixture of soap and glycerol that was dissolved in residual methanol in solution with the BD which precipitated out when the methanol evaporated. It can also be from polymerized VO.

I would second that john. It will happen if the bio has not been properly de-methed or settled for long enough. Even if it is water washed by a non aggressive method ie gently misted or bubbled it is still a possibility.

Hi John,

quote:

Originally posted by john galt:
That is likely a mixture of soap and glycerol that was dissolved in residual methanol in solution with the BD which precipitated out when the methanol evaporated.

If the biodiesel hs gone through the filters and is in the "internals" of the fuel system, how does the methanol evaporate out?