I’ve been buying B100 BioDiesel from a fellow who delivers the stuff to my driveway. First batch of 67 gallons seemed to work just fine. Truck exhaust smelled fine, and after one replacement fuel filter I thought I was set.

Then I got a second batch of B100 from the same fellow, a lovely 110 gallons in two 55 gallon drums. Price went up by .50cents a gallon, and the quality went down quite a bit.

I ran about 10 gallons in the truck and immediately I noticed that the B100 seemed a bit thick. So I pulled off a sample, and continued to fill the truck up to the halfway mark. I had a funny feeling, that said to not go any further than this. Took the sample and put back under the boat canopy where I forgot about it until the next day. Next day I find this!
BioDiesel Sludge

Holy crap! &*&^%@#!

Gathered myself up and headed over to the BioDiesel Forums where kind folks helped diagnose the problem.

Number one diagnosis: Soap in the fuel due to incomplete reaction in the conversion from WVO to BioDiesel.
Number two diagnosis: Soap in the fuel due to incomplete reaction in the conversion from WVO to BioDiesel, and inadequate washing and drying.
Number three diagnosis: Just plain poor conversion.

Suggestion: Take a liter or so of the Bad B100 and try to wash it with an equal amount of water. This is what I got:


The top layer is BioDiesel, the center layer is Soap, and the bottom layer is water. There should be two layers, BioDiesel and clear water. The Mayonnaise looking layer is bad and will gum up the fuel tank the fuel filter, and perhaps the injection pump and injectors. Not a good situation.

Letting it rest overnight I get this:

Mayonnaise Day2

It’s separated out better, but that center layer, at the most should only be a very thin, thin line if there at all.

I am bummed.

Up next, I will siphon off the BioDiesel at the top of the jar, and try to re-wash and see if any more soap is generated.

Will also test the BioDiesel using the “27/3” method, and will try to reprocess an unwashed batch of the Bad BioDiesel and see if that corrects things.

I’m still bummed. And though the Producer of the Bad BioDiesel has said he’ll take care of it and make things right, I have my doubts.

I’ve been burning 100% B100 BioDiesel for several weeks now, and so far so good. The truck seems to like it just fine, though my mileage appears to be down at least a couple miles per gallon. I suppose this is because the BioDiesel has less BTUs. At any rate, the exhaust smells better, especially once it’s warmed up. I have a 55 gallon drum of the stuff along side the 55 gal drum of 100% WVO already de-watered and filtered to 1 micron. Question is do I continue to burn the BioDiesel and eventually set up my own BioDiesel Appleseed processor, or do I take a chance and blend the two and keep my fingers crossed that I don’t sludge up my valve train and Bosch P7100 injection pump. These things are expensive and the heart and lungs of the Cummins.

Speaking of Sludge, I have been getting a Water In Fuel (WIF) light on the dash. I immediately thought that I may have gotten a bad batch of BioDiesel. I was warned by several folks that I’d go through a couple of fuel filters when I started running BioDiesel, because it’s a very powerful solvent and will clean out my tank, fuel lines etc. The old Dino Sludge will be cleaned out, and clog up my filter prematurely until the system is sparkly clean. So I drained the fuel filter bowl yesterday into a clean mason jar, and then pulled the fuel filter. Fuel Filter didn’t look so dirty, though there was some sludge in the fuel filter bowl. There was one pea sized chunk of white spludge looking stuff, that I suspect was shorting out the WIF wires. There was NO water in the fuel. This the second time in a week that I’ve drained the bowl, and neither time did I find water. Put in a new filter and have set aside the jar of biodiesel along with a jar of WVO to see if anything settles out over the next week or so. Then I’ll put them both in the fridge and then the freezer and see if they solidify or separate.

While I was at it, I removed the bowl from the fuel preheater to replace the filter/strainer. Oh, oh. There’s sludge, and this is not the good kind of sludge. This is black slimy stuff that is fungal in nature and is known for doing some serious damage to fuel systems. This very truck had it’s own fuel tank dropped a year or two ago, when the previous owner got a bad batch of Diesel. He paid a bunch of money to have the whole fuel system purged and cleaned. He then ran an additive in his fuel every fill up to kill off any remaining nasties. Well the dealer missed this filter.


I am pretty sure this bug didn’t get introduced with the BioDiesel, rather it was old funk that was missed. At any rate the BioDiesel in the tank got a double dose of anti-fungal treatment. This stuff is NASTY. I wonder if there is any other of this stuff in the fuel system.