Algae can be a problem, but this may not be your issue. Algae slime will usually settle in the tanks, since the microbes actually live in the water that settles in a tank, and the black crud is made by them. It will show up in filters, but a "layer" of the black stuff in the tanks may be another problem.

I had a black crud issue with my truck early on. It turned out to be "asphaltine". The Cummins in my truck really "cooks" the fuel that get returned to the tanks and causes the carbon molecules to bond in such a way that they will be larger black particles that can have a "slime" like appearance. I took a dual approach to the problem and put on an Algae-X inline fuel treatment device and started adding a little PRI-D fuel additive (a fuel stabilizer, not a biocide that is usually sold at boating shops) to tanks for a while. Problem all solved and has never returned.

Don't ya just love all the problems that crop up over a simple thing like fuel?

I've been wondering if it might not be asphastines, I think I'll get some PRI-D to use after the biocide has had a chance to work.

I've also given that Algae X inline some thought, how much was it?

It could be a bad injector o ring. We had a o ring break and would send oil into the fuel tank. It was on a international DT530

Originally Posted by VARITHMS

It could be a bad injector o ring. We had a o ring break and would send oil into the fuel tank. It was on a international DT530

Was the soot high in your oil? I recently had an injector and head gasket replaced and that sounds like soot... I need to do a sample on my oil, I've had a weird flutter ever since.

Update.

The biocide didn't even touch the coating inside the tanks after I filled and treated them with a strong shock dose, then let it sit for 5 days. Since Monday I've ran the tanks pretty low...I guess that now it's either soot or asphaltines, an oil sample should narrow that down once I get enough miles on the oil.

Originally Posted by paul 1052

I've been wondering if it might not be asphastines, I think I'll get some PRI-D to use after the biocide has had a chance to work.

I've also given that Algae X inline some thought, how much was it?

I put on the Algae-X a little over 2 years ago. Can't remember the price then. I did a quick check online and found the LG-500 like I have for around $250. I worried about the price, since it is easy to get burned by snake oil products, but this one definately worked for me. I have not had another fuel related problem since I put it on. Fuel always looks in the tanks just like it came out of the nozzle at the pump.

Using the PRI-D will help keep the carbon molecules from bonding because of the engine return heat. I have found also that Schaeffer's Diesel Treat also will do the same job. Both are relatively easy on the pocket book since you don't have to add much. Schaffer's is about 1 oz to 15 gallons of fuel. PRI-D is close to that ratio. I would always buy it in gallons for best price and then fill smaller 8 oz bottles and keep them on the truck.

I am pretty sure what I had was asphaltines and not soot. My oil sample soot levels are always in the .1 -.2 range and no fuel in oil that would show an injector problem.

Originally Posted by paul 1052

Was the soot high in your oil? I recently had an injector and head gasket replaced and that sounds like soot... I need to do a sample on my oil, I've had a weird flutter ever since.

Update.

The biocide didn't even touch the coating inside the tanks after I filled and treated them with a strong shock dose, then let it sit for 5 days. Since Monday I've ran the tanks pretty low...I guess that now it's either soot or asphaltines, an oil sample should narrow that down once I get enough miles on the oil.

The oil was not tested. All I know is in about 10 min of running it would pump 5-6 gallons of oil into the fuel system. The fuel was as black as the oil.

Hey man I wanted to see if u ever got to clean out ur tanks I got the same problem please get back to me my fuel filter keep Geting clogged up

Paul 1052. Man what u said is totally what I'm going threw right now wanted to see if u ever got that crap cleaned out of ur tanks

Did u ever find out how to get that out of your tanks I got same problem please help!!