I buy bio-diesel froma reputable dealer. I was burning B-99 this summer and works great. Now that it is cold i blended it down with #1 diesel to a B-20. On cold or cool days temps at 40 and below my fuel pressure runs low. It runs at 5 or 6 lbs at 2000 rpm but at idle it runs at 8 to ten. The truck runs good no power loss but when it gets cool the pressure drops. I didnt think the bio would be gelling as I have #1 diesel blended to make it B-20 and I double dosed the power sevice. Any ideas? Kind of worries me with the low pressure.

 

Your pressure reading is post filter, correct?

Any chance you just have a somewhat clogged filter?

 

Bio has a habit of cleaning your fuel tank for you and dumping the remnants into your fuel filter... Have you changed it lately??

 

Bio seems a bit thicker than diesel at lower temps since it clouds earlier than diesel. Id put some of the stuff from the place you usually go into a couple jars and see at what temp it begins to cloud. Give you an idea when to be on the lookout. Stuff will start to clog filters at that point just like really cold diesel. Maybe mix in some power service diesel treatment? Youd need a little diesel in the tank for it to work though, not B100.
Careful with low pressures on that truck since youll have a VP44 those rely on fuel for lube. Bio lubes better than diesel though, so who knows.

 

I've seen lower fuel pressures when cold even with straight #2.
Always figured it was due to the viscosity changing.

 

My fuel pressure is at the pump at the shrader valve. I did notice it does start to cloud at that temp but pours easily. I am aware of the cleaning bio does to the system . I had my whole sytem apart including cleaning the tank before using the bio. I had a pickup tube problem is why I did that. I didnt think B-20 would bother at those temps. I have read on here guys running B-50 into the 20's and no problem. My filter is new. That was the first thing I checked so im sure it is ok . I have been running the B-100 all summer so im sure my system is cleaned if there was any trace of crud left. Must be the because of the bio thickening up. I run #2 year round even sub zero temps and no problems or pressure drop.

 

I would expect excessive glycerin content in the biodiesel may be the culprit. I received a bulletin from the company that does our fuel testing last week that said a lot of biodiesel samples were out of spec. for excessive glycerin content. Luckily our B-20 was well within all specs. but our supplier also knows that we do random testing with an independant lab.

 

whos a good source for oil and fuel testing? I want to run this stuff soon but I want to also do oil analysis along the way. Checking the bio is a great idea.

 

We use Filtration Specialties here locally for the fuel testing, and Titan Labs. in Colorado for our oil.