Any one elses MPG Dropping??

[06_Jetta_TDI]

My mileage has also dropped. I can remember the Dealer telling me when I bought last October that the 06 was set up to handle the new diesel coming out in 06 and that the mileage should actually get better when it comes out... not worse. I have always had a hard time believing a car salesman and I'm beginning to think I was right again.
If you read this article which was posted in another forum, the new lower sulfur formula ULSD that is coming out - Mileage is expected to drop. Someone earlier said that ULSD is going to be required 10/15...this article states that we should start possibly seeing it around mid year. I have a feeling lower mileage might turn out to be a standard and that we are starting to see this newer role-out of ULSD vs. LSD that they talk about in this article....any thoughts????

http://www.masstransitmag.com/publication/article.jsp?pubId=1&id=340

 

[Leedogg]

Since a few have posted about the lil sticker on the pump- the sticker that says not for 07 and newer means it is the same LSD(500ppm sulfer) D2 that we've all been running....so that is not the reason for a drop-or increase- in your mileage at this time. All diesel pumps should have an identifying sticker by now as to whether it is LSD or ULSD...


but in response to this thread- I have noticed that I am getting worse mileage too- though minor. I was averaging right at 42- now I am right at 40.8...I figure that is normal with the 1) A/C use 2) a little more aggresive driving and 3) about 150 pounds worth of stereo, bowling ball, jump box, etc in the trunk. My best ever tank was 43.8 with no a/c, an empty trunk, and painfully slow driving, and worst ever of 38.8 driving it like I stole it....so 40.8 now seem about right to me. Still makes me smile everytime I fill up.

 

[06_Jetta_TDI]

With all do respect to your comment. I seriously doubt that with the first few tanker loads of ULSD dropped at the filling station will they change the stickers immediately, as there will no harm done in existing vehicles. I'm sure they have to make a judgment as to how diluted the old LSD in the tanks has to be before they can swap stickers. A merchant cannot let their wells go dry so to speak before they start getting the new ULSD. But...I hope you are right about this and it is not because of this new fuel...altho if you are right...this means there will be an additional drop in MPG once they do start distributing the new fuel, which saddens me even more....

 

[buckeye96]

My mileage has dropped in the past 6 weeks. I run the AC at 74 and don't use it that much. I have noticed that when I used to go to work (at a certain point) my MPG was around 38. Now at that point it is around 31.

 

[farfrumsanity]

I was under the impression that the sulphur in the diesel has lubricating qualities, and should not affect the milage, but the refiners could be diluting with diesel 1, how would we know except for the drop in milage, and the could say it was due to lower sulphur. My John Deere manual says that it is possible to put 25% diesel 1 in the tank for winter use, with a loss of power and increased fuel consumption due to the lower cetane rating of diesel 1. It is used for anti-gelling and easier starting in the cold.

 

[Leedogg]

With all do respect to your comment. I seriously doubt that with the first few tanker loads of ULSD dropped at the filling station will they change the stickers immediately, as there will no harm done in existing vehicles. I'm sure they have to make a judgment as to how diluted the old LSD in the tanks has to be before they can swap stickers. A merchant cannot let their wells go dry so to speak before they start getting the new ULSD. But...I hope you are right about this and it is not because of this new fuel...altho if you are right...this means there will be an additional drop in MPG once they do start distributing the new fuel, which saddens me even more....

You are correct.

I asked the station manager when I saw him if they was starting the swap yet- he said 'not yet' but they had to put the stickers on already identifying it as LSD. He also said that they would have to 'roll' the fuel in the tanks a few time and then have it tested to make sure it meets the ULSD stadard before they can label it as ULSD. So you are correct that some places could be cut with the USLD by now-yet not labels as ULSD.

According to everything I have read on the ULSD(ALOT of searching around...very little info out there, compared to what I thought I'd find) you shouldn't see more than a 1% drop in economy due to the aditional washing of the fuel..thins it out some...BUT the Cetene is actually higher on ulsd(51) compared to as low as 42 on lsd out there right now...so it should balance out fairly close. I hope it doesn't cost anymore fuel economy loss than that cuz then I'd be under 40 mpg and I'd hang myself!<---joking of course

BTW- tank before last I got 42.5 by driving for economy but still running A/C...I think the A/C costs me about 1.5 mi/gal on my car compared to what it got before summer. The rest I contribute to my right foot!

 

[farfrumsanity]

The strange part is that the stations around me have just started putting the LSD stickers on the pumps, and I think the ULSD comes into effect in August, I would think thet would wait for the ULSD, but it might be Gov't telling them to place them on now. If the Cetane rating is increased in the ULSD, the milage should stay the same or improve.

 

[Leedogg]

I think June 1st they had to label it- cuz they were never labeled around here either...now every place I go has the label.

 

[Dickhein]

I'm a newbie, still looking to buy my TDI. But I have a Honda Civic Hybrid whose mileage approximates the TDI. In 60K miles, I've noticed two things which affected my mileage:

Replacing the OEM tires with Michelins cost me about 2 mpg. The originals are designed to offer low rolling resistance while the Michelins are designed to maximize tread life.

And the really annoying factor is that on more than one occasion, I have pumped more gas into the tank than the capacity of the tank. This has happened only in Florida. I have complained to the clerks but they just shrug their shoulders.

One other thing, a sort of "inconvenient truth". if you have a GPS, compare the GPS speed with the speedo. German vehicles speedos tend to read a little fast.

 

[Leedogg]

One other thing, a sort of "inconvenient truth". if you have a GPS, compare the GPS speed with the speedo. German vehicles speedos tend to read a little fast.

But the odometer's are nearly spot on...the computer knows the 'real' speed of the vehicle.

 

[bobjackson]

true, i have a scangauge which display mph. everytime I drive by the the roadside radar its exactly the same and my speedo is roughly 5mph positive

 

[06_Jetta_TDI]

I disagree on the odometer...I checked mine against the road miles and mine is off for sure. I talked to the dealer and it was kinda funny. He said is it off by 3 or 4 MPH? I said - Yes, probably like they all are - right? Well yes they are all off by that much and there is nothing they can do to calibrate them, he said they have swapped units out in the past and they are all the same. So I guess I am SOL. He did say he was told even tho the MPH is off the odometer is right- but hes wrong. The part that really blows about this is that I'm really not getting 40 to 42 MPG - it says that on the odometer, but thats not actual miles. Its not way off tho - I think for every 100 miles I go the Odometer says 101.
Test it against the signs on the highway...tell me what you see. When my ODO turns the tenth mile - that sign keeps getting farther and farther away.......

 

[rpm]

Mileage signs aren't always right

Test it against the signs on the highway...tell me what you see. When my ODO turns the tenth mile - that sign keeps getting farther and farther away.......

On a trip back from Illinois last winter I did just what you say. I was spot-on all through Ohio. I was fine on the Southern Tier Expressway in NY also. However, any time I was near a large city, I found that the signs were not consistent at 0.1 miles apart.

Bottom line for me is that I think my Odo is accurate about as close as I can measure it with my stock tires on the car.

 

[DieselDavid]

everytime I drive by the the roadside radar its exactly the same

I've noticed this too. The speed displayed on the automatic climate control and the speed displaced on the roadside radar thing always match. The speedometer on the dashboard is not accurate but the error is not a constant number of miles per hour. Rather the faster I go, the more the dashboard speedometer is wrong. It seems to be erroneous by maybe 5%.

 

[Leedogg]

Well I checked my odometer last night on the way to Louisanna....over 30 miles- My odometer was off by about 30 feet...to the good. My tenths on my trip meter was hittin .3 at every sign perfectly.

on a side note- my mileage dropped to 38.1 mpg at 82(indicated) on cruise control...darn it! My Superduty woulda been getting ~15.LOL

 

[farfrumsanity]

The toe in is important to milage, I read a test of the Honda Insight, and it was twitchy at speed, they increased toe in 1 degree to get it more stable, and the milage dropped by 2 MPG. I have an aftermarket Nav unit and at 75 MPH indicated the Nav shows 72, but as the speed decreases, they get closer together, at 35 indicated the Nav unit shows 34, still off but closer. The nav unit somewhat agrees with the roadside radar units, but I don't know how well they are calibrated. The nav units are true to 35 feet from the satellites, and most of the time I'm hooked up to 6 satellites. From all the posts it would seem that the speedo is high, just how high is open for discussion. Does anyone know if the sulphur does indeed lubricate the injection pump and has little to do with milage, or does it help milage?

 

[H8-I270]

I know the odometer is off on mine. My commute has been 80 miles each way for almost 10 years. Now it's 83. I must have moved up the street and didn't know it... Now how to get VW to correct it!

 

[06_Jetta_TDI]

I just looked on the VW web site. 17" wheels are an option on the Jetta. I almost bet that the speedometer and odometer are off a bit to make up the difference should you choose to go with the 17" tires. They would have to worry about making different speedometers for the different size wheels, just makes it easier/cheaper for them. I might price out some 17" wheels when the tread is gone on the factory tires. Not sure how worried I am about it tho, but if I do choose to go to 17"...I bet my mileage goes up a bit

 

[farfrumsanity]

Most of the time when the wheel size goes up, the aspect ratio goes down to maintain the diameter of the tire, 205-70-15 = 215-60-16, within an inch or so of rollout. There will be error, but only 1 mph or less. If you go from a 205-55-16 to a 255-55-16 there will be much more error. Measure the tire circumferences to see how much error you get.

 

[BioThomas]

No need to measure. The circumference is calculated with the following formula:

In other words, C = 15*2*pi v.s. 16*2*pi.

 

[DieselDavid]

Tire Size Calculator

Try this on for size!

http://www.miata.net/garage/tirecalc.html

 

[quartermeter1999]

No need to measure. The circumference is calculated with the following formula:

In other words, C = 15*2*pi v.s. 16*2*pi.

Where did the "15*2" come from?? It's Pi * dia and not Pi * radius.

The "d" is the actual diameter of the tire and has nothing to do with the wheel size.

 

[BioThomas]

Where did the "15*2" come from?? It's Pi * dia and not Pi * radius.

The "d" is the actual diameter of the tire and has nothing to do with the wheel size.

Yes, you are correct. I thought the 15 was the radius. I guess that it is the diameter, judging by your question.

 

[candrews4tdi]

My fuel mileage on my 05.5 Jetta 5-spd was falling off right before my 10K oil change. But when I switched to Elf Evo CRV 506.01 and started using Diesel Kleen

http://www.powerservice.com/dieselkleen_cetane.asp

My mileage actually improved about 2-4 mpg on average. And I had my best average tank averaging 43.5 mpg recorded with a fill up right after the oil change. I average a 60 mile daily commute with about 30% slow/go and 70% highway. My car just turned 15K on the odometer.

 

[tdiman]

poor mpg

check your tire psi before you drive off first thing in the morning wiil affect mpg also i run right at 34 psi all around makes a difference also you might try a bottle of stanadyne pefomance you can buy at www.tdiparts.com under fluids vw recomends and a great article about this product

 

[danielttt]

Mine drops in the summer

I live in Florida. Bought my '05 TDI Wagon in Dec 04. Fuel mileage was great and steadily improved until the heat hit hard last summer. Fuel mileage went from low to mid 40's to mid to upper 30's. One of the learned geeks here told me the efficiency of the turbo intercooler and the drag from the A/C could be quite significant. That all makes sense. It's better this year but I'm probably driving somewhat more conservatively than last year. Summer seems to suck for me and fuel mileage.

 

[8606]

My last tank(no fuel additives), 42.17mpg, previous tank with Stanadyne (42.87). So Stanadyne wasn't worth it for me. 20K service tomorrow, so hopefully mpg increases after service.

 

[06_Jetta_TDI]

DieselDavid - Nice tire calculator! Moving from a current 205 55 16 to a 205 55 17 makes a 2.4MPH difference. This would be much closer to actual speed and odometer than I am now, I think it will still be just a tad under actual speed....now to find a set of 17" wheels before my original tires wear out.

 

[quartermeter1999]

I just found out why our mileage has been droping. The owner of the place I buy alot of diesel told me he has been getting the ULSD for a couple of months now. They are getting it now to flush out their tanks.

Once the date comes for the required change the PPM reading should be low enough to comply with EPA. We've been burning this stuff and didn't know it.

They got ULSD the same time they put the stickers on the pumps to tell us not to use this diesel in 07 cars.

He told me this last sunday July 9 06.

That should explain the reason for our mileage dropping. THis new ULSD is giving less mpg. Thats explains why it started dropping a few months ago. Mine went from 46-48 to 41 mpg. That sux.

He's going to find out the Cetane rating of it from his dealer.

I'll let everyone know this sunday when I fillup.

 

[robrichtx]

ULSD - Lower mileage

I just found out why our mileage has been droping. The owner of the place I buy alot of diesel told me he has been getting the ULSD for a couple of months now. They are getting it now to flush out their tanks.

Once the date comes for the required change the PPM reading should be low enough to comply with EPA. We've been burning this stuff and didn't know it.

They got ULSD the same time they put the stickers on the pumps to tell us not to use this diesel in 07 cars.

He told me this last sunday July 9 06.

That should explain the reason for our mileage dropping. THis new ULSD is giving less mpg. Thats explains why it started dropping a few months ago. Mine went from 46-48 to 41 mpg. That sux.

He's going to find out the Cetane rating of it from his dealer.

I'll let everyone know this sunday when I fillup.

I will double check. My wife works in the Petroleum Industry and will be able to source this out with the major carriers.

I really hope you're wrong Quartermeter - for all the right reasons! Unfortunately, I am afraid that you are either right, or a bunch of us are losing mpgs for no apparent reason.

Rob