Diesel MPG decreasing..

[campntn]

What could make a diesel get less MPG? It was getting 21 on the highway, but now get's 17-18? Filter change needed? It's time for a service. I've never had a diesel before this one.
Thanks!
Mark
04 Chevy 2500 HD Duramax

 

[Netem]

The first thing I would check is the air filter. Did you get your fuel from a different place than normal? Some people have said there mpg decreased with the new low sulfer fuel. The winter weather could affect it some.

 

[katkens]

I always lose mpg in the winter its the blend of fuel that's used. They add #1 diesel and anti-gel agents to keep the flow going and thus less btu's less mileage....Ken

 

[jbeletti]

ULSD?

Jim

 

[vangoes]

I've seen a definate drop from 2 - 3 mpg since I have had to burn the ULSD. My mileage towing the BH has always been around 12/mpg and my last trip over Xmas (900 miles) I only averaged 9.25 mpg. This was my first trip that I had to run ULSD totally.

 

[Bob&Patty]

Rats !!!!!!!!!!!

Never thought of that, no wonder my MPG is down. Thanks for ruining my day. Bob

 

[billd]

Combination of ULSD and winter blends in some areas, out west it is ULSD.

Bill

 

[Wild Bill]

My Duramax is currently averaging 10mpg towing and 16mpg solo. This was on my trip up to Oregon from Cali towing and then back to Cali solo. I may look into getting a programmer so I can change things up for power or mpg. Not sure yet though.

 

[Netem]

I run Stanadyne, good for the motor since they lowered the sulfer content and helps alittle with the power and mpg. Dealer tells me its the only one approved by GM.

 

[creeper]

Possible causes, Fuel, EGR, Fuel filter, air filter, bad injector to name a few.

 

[DougLynne]

The Diesel Performance guys that installed my Exhaust Brake were telling me at the RV Show that I should be adding an additive to my fuel for the ULSD. I had never heard of that, but apparantly, the reduced sulphur has reduced the libricant in the fuel and older trucks need an additive. The newer engines are build to handle the reduced lubrication. Has anybody heard anything about this?..../Doug

 

[N9MB]

What could make a diesel get less MPG? It was getting 21 on the highway, but now get's 17-18? Filter change needed? It's time for a service. I've never had a diesel before this one.
Thanks!
Mark
04 Chevy 2500 HD Duramax

I would be thrilled to get 17-18 mpg! My average is around 11.5 ! Seriously, you will see a marked decrease in mileage with winter blends, typically a couple of mpg and also consider the additional winter warm up time. Wait a few months and see if it doesn't improve.

Good luck

 

[vangoes]

Heading out tomorrow and I will be trying a fuel additive to see if my mileage improves from my December trip. If it does, I think that will be proof that it is the ULSD that is causing our drops in mileage. Will keep everyone adivsed.

 

[jmgratz]

I was getting 10-11 towing 17-18 not towing prior to ULSD. Now I am getting 8-9 towing and 15-16 not with ULSD. I have a 99 Ford F350 7.3 with a full Banks system including exhaust brake, trans-command. The only change has been in the fuel. Thanks US Government for your decision to require ULSD. Not only has the price gone up but the MPG has decreased. I was also told by a Ford dealer the ULSD is causing a rash of tubo failures.

 

[Larryheadhunter]

what the **** is ULSD? Since I am heading toward Fresno, it may be cold. I do have a new 2008 truck so I am not sure what to add if anything. At the diesel pumps it says #2 pump. Does that mean anything?

 

[jbeletti]

ULSD = Ultra Low Sulfur Diesel. I believe that is all you'll be able to buy.

Jim

 

[Larryheadhunter]

what the **** is ULSD? Since I am heading toward Fresno, it may be cold. I do have a new 2008 truck so I am not sure what to add if anything. At the diesel pumps it says #2 pump. Does that mean anything?

Should I add any fuel additives and if so which?

 

[htneighbors]

My 1-ton is my work truck, used daily, ( avg 1250-1500 mile/week) currently LOADED with lots of tools for my work. I have been averaging 18-20 mpg. I'm interested to see what I get once I get my Cyclone. ???

 

[katkens]

The problem with additives is if you decide to use which one. They all have there sales pitchs and special ingredients that are the cats meow. If one goes to any of the fuel manufacture sites Chevron etc. they all recommend not using additives . I was researching an came across a site on this subject by some type of chemical engineer. It was very lengthy with words I would have had to look up to fathom everything. The main thing I picked up was a lot of the chemicals in additives combined with whats already there in ULSD can change chemical make ups into acids and corrosives. I guess for now I'm just going to use my bucks on regular maintenance and not on additives.....Ken

 

[Ray LeTourneau]

No ULSD in the Corpus area!

Most places I have bought fuel here only have LSD fuel. I've been using Shell and Valero. I tried using Diesel Kleen and didn't see any improvement in mileage but the truck seems to run better. I know most of the Ford owners here are unhappy with the mileage on the newer Power Stroke. One guy with a new F250 was getting 6 to 7 pulling his Sundance. He's hoping that will improve once he gets more miles on it. There's a thread going in here where folks are reporting their mileage and mine is right in line with most of the GM owners. 10 to 12 towing and 18 or so hwy. Around town shopping and what not we get 16. I'm happy with that. BTW Diesel in Corpus is $3.39. Just out side of town $3.15. What's up with that? How much is it in the Valley?