poor mpg on biodiesel

[nogama3]

guys,

i was running at approx 50% bio and 50% normal diesel and then at 80% bio and have noticed that the car will drink heavily when using bio. Recently I only managed 74 ish miles on half a tank of fuel which was mainly driving around the town and a little motorway mileage. I know that I normally get double that amount quite easily.

any of you guys had any problems?

Sal

[ilomax]

I get noticeably worse fuel mileage with bio.

Just switched back to #2, because Bio's price tag is rediculous right now and I have noticed, not just an improvement in MPG, but performance aswell.

With a tank of bio I was lucky to get 370 miles on a tank.
With the #2, I'm on track for 400 miles and possibly more.

I use my car for driving around town aswell.

[Turbinepowered]

guys,

i was running at approx 50% bio and 50% normal diesel and then at 80% bio and have noticed that the car will drink heavily when using bio. Recently I only managed 74 ish miles on half a tank of fuel which was mainly driving around the town and a little motorway mileage. I know that I normally get double that amount quite easily.

any of you guys had any problems?

Sal

Only seventy four miles on a half tank of fuel is ridiculous. Having any performance problems, stuttering, poor throttle response? In other words, clogged filter symptoms?

[burnt_servo]

what kind of car / engine do you have would be the first question .....

i'm wondering if biodiesel  might benifit from a injector nozel with a slightly different spray patern ?

[burn_your_money]

is this homebrew or store bought?

[Greasecar]

I've noticed about 10% fuel economy loss with B-10 from the pump on my Rabbit.  I've been getting around 30MPG on B-10 and around 33MPG w/ #2.  Either way the milage is real crappy for a 1.6L.

I haven't noticed it as much with my other diesels.

[nogama3]

right guys, answers to the questions are:

the car is a golf mk3 1.9 TD AAZ engine with additional intercooler, performance wise it seems to be running fine . i have added an inline fuel filter so i can see if the filter clogs up but this is clear.

the bio is bought from a local manufacturer who seems to know what he is making and asks for regular updates of performance/consumption.

i have now filled up with normal diesel and its running approx 75% normal diesel 25% bio and the car is running better and improved mpg already! 75 miles and the needle hasnt moved yet....

[thedeezel]

Do you have a locking gas cap?  Seems like someone jacked some of your fuel, 74 miles to a half tank, that is definately not right.

I would think you would have been running lots of black smoke with that much fuel going thru the motor, or the car would have been running really rough.

When I have run Bio in the past, I have seen n o more than a 20% decrease in mileage, from 40 mpg to 30-32 mpg in my Jetta.

Something fishy going on...

[TedV]

Something fishy going on...

74miles/5gal= 14.8 mpg  

some one stole your fuel?
you have a leak and puddle of fuel someplace?
fuel gauge screwing up?

[nogama3]

my cars always locked in the garage at night and its at a secure car park at work so i dont think anyones nicked the fuel. there appear to be no fuel leackages as the garage floor is clean with no signs of wetness, even around the engine bay. have to say though, the egine is idling around 1100 rpm and doesnt seem to go any lower, i have took it to a diesel specialist who coulnd't get it to go lower. i may need to shave the adjust arm slightly to give it more adjustability
because i have a dual exhaust trim the smoke wasnt very much so you couldn't tell if it was running rich or not. gonna monitor the mileage from now on

[TedV]

forgot the most common problem with VW mileage.  

speedometer gear cracked and intermittently rotating on the shaft?  you drive the miles but speedo don't show it