Diesel Place banner

1 - 19 of 19 Posts

·
Registered
Joined
·
218 Posts
Discussion Starter #1
What the heck causes the loss in fuel economy?? I was averaging 17 mpg up until a couple of weeks ago and bam, down to 12. My driving for that mileage was 75% city and the rest highway. Is the fuel being mixed with K1 do it ? If it is then is there less btu's in kero than diesel. Also the exhaust smells alittle different now, not quite as propanie as before.
 

·
Registered
Joined
·
58 Posts
Wow and I thought 16 was bad!!!



I noticed that my mpg seemed to drop back around the first part of Nov. I assumed that they had started selling winter diesel (blended #1 and #2 diesel...less power/less "gelling") around here. Since then I've been getting around 16mpg on tanks where most of the driving was city and around 18mpg on tanks where it was mostly highway.
 

·
Banned
Joined
·
6,539 Posts
Mine dropped also in the last couple of weeks. Must be some super diluted fuel. Don't know my mileage but I know haw fast the gauge normally moves during the week. Usually two day in the first 1/4 tank.... now maybe day and a half.
 

·
Registered
Joined
·
26 Posts
I've seen about a 1 to 2 mpg drop. I'm currently using Stanadyne Performance Formula.
 

·
Registered
Joined
·
2 Posts
The reason you are getting terrible mileage, is the same reason all of us with diesels are. The fuel companies dilute the fuel to reduce the gelling in the tanks at the gas stations. The same concept when adding fuel additives, it dilutes the fuel, believe it or not and lessens performance and mileage very significantly. I was told that anti-gel additives were a joke, and I believe it. I haven’t had a problem all winter and we have had some weeks with -0 conditions all week long. I have a buddy in the diesel fuel business and he claims that all the stations add anti-gel additives to their fuel in the frigid conditions to keep the fuel they have on hand from being gelled up and worthless.
 

·
Registered
Joined
·
939 Posts
I am getting right around 15mpg now...was getting 17-18 mpg with ~80% highway driving..


Bob
 

·
Registered
Joined
·
1,191 Posts
I've noticed that in the winter my milage goes down about 3mpg. 2 Things, different fuel blend for winter, and I also let it idle about 15 minutes per day longer than I normally would. I start it in the morning and then make a cup of coffee before I leave for work, and before clocking out I start up the truck for about 7 mins. I know most say you don't want to idle for more than 5 minutes, but I would rather have a more viscus(sp?) oil than drive away with a cold engine.
 

·
Registered
Joined
·
141 Posts
I'm getting 15-16.... was getting 17-19 during warmer weather Now Idleing in the morning and before leaving work for about 15mins. Also, fuel was $1.39 ...went to $1.49 this morning
-- Hess
 

·
Registered
Joined
·
239 Posts
Mine as dropped also. 14/15 from 16 mpg. We are most certainly on winter blend here at work. A lot of my miles lately have been highway and I was hoping to see an improvement. 40k and have not seen any improvement in milage.


Still better then a gasser!
 

·
Registered
Joined
·
6,995 Posts
Don't forget about all the thick oil in the trans and rear ends, plus the stiff tires don't flex as easy so it takes more power to move.


Does anyone else see it takes 3-5 miles before mine shifts into OD or lock up the converter w/ the cold weather.


That hurts the fuel economy too.
 

·
Registered
Joined
·
665 Posts
I just filled up with Shell Premium at a nearby State Highway station, milage jumped from 16 to 18. I'm in San Antonio Tx and our tempatures are between 37 and 70 right now.
 

·
Registered
Joined
·
227 Posts
Running higher RPMs until the engine warms up is a function of both gas and diesel engines these days. It too carves into mileage. Watch you tach and you will see that the engine runs faster in each gear until the engine reaches operation temperature. This feature helps the engine warm up quicker and cut emissions to the environment. Of course thicker oil in the crankcase and differentials also effects fuel economy too as does the blended fuel.
 

·
Registered
Joined
·
218 Posts
Discussion Starter #14
I haul boats around the yard etc., maybe I let it idle and hauled more than I thought. Took a run about 60 miles highway filled to the brim and the gauge barely moved like it used to, also it has warmed up. I know I let the truck idle alot more than I admit, nice getting into a toasty truck when it's freezing ass cold! Thanks for the replies everyone.
 

·
Registered
Joined
·
868 Posts
Winterized fuel is blended with more light petroleum stock, such as kerosene, to reduce the pour point and other relevant parameters, so it will flow in winter. As a result, the BTU per gallon falls off. So when you buy a winterized gallon, you are buying fewer BTU of energy per gallon. Less BTU/gallon = less mileage/gallon.
 

·
Registered
Joined
·
101 Posts
LARSONEM said:
Running higher RPMs until the engine warms up is a function of both gas and diesel engines these days.  It too carves into mileage.  Watch you tach and you will see that the engine runs faster in each gear until the engine reaches operation temperature.  This feature helps the engine warm up quicker and cut emissions to the environment.  Of course thicker oil in the crankcase and differentials also effects fuel economy too as does the blended fuel.
You beat me to it. We also can't forget about the trans temp. Untill the trans gets up to temp it wont alow a full engagement of over drive which also coresponds to higher rpm. I think I read that in the owners manual.
 

·
Registered
Joined
·
218 Posts
Discussion Starter #18
False alarm, I checked with half tank gone and it came out to 15.7 mpg. I must have run the truck silly or idled it forever the last tank.
 

·
Registered
Joined
·
57 Posts
Mine dropped 2-3 mpg too.
I live way down south near Houston. Do they use winter blends down here too? I probably won't see below 30 this year and I know(hope) it won't get below 20.


Can an additive overcome this?Edited by: GMCDURAMAX
 
1 - 19 of 19 Posts
Top