Help with crappy mpg

Hi,

I've now got about 5kmi on my 2012 JSW. I am terribly disappointed in the mileage we are getting (see fuelly badge at bottom, ~30mpg mixed), and I'm looking for suggestions as to where to start troubleshooting. Some background:

• I used to have a 2000 Jetta TDI and mostly got in the low 40's under the same conditions
• I am filling up at the same stations as I did with the old car, B0 to B5 with seemingly good turnover
• I have yakima round bars on the JSW, but only put a box on top for trips
• I have my tires between 37-40 psi
• 50-50 city/highway.

What I'm looking for is suggestions as to where to look to start troubleshooting this thing. The 30 mpg seems extraordinarily low...I would not be posting this if I even had ONE tank above 35 mpg. Any ideas would be welcome. Thanks!

Describe your driving style.

If you're not an overly aggressive driver, then I'd bring it into the dealer and have them take a look. It's still under warranty.

We could probably use a little more information here, like your transmission (6 m vs DSG). Off the top of my head, I can think of a couple things to check out. It seems from your fuelly that you drive about 75 miles/day which is quite a lot for that low mileage, one would think instinctively that you should be getting much better fuel economy even with 50/50 driving. What does your average mpg read when you are driving strictly on the highway, does it hit the low to mid 40's? How fast are you driving, and how much stop and go traffic do you drive in, both are mileage killers. SF is very hilly, is that part of your commute? Some on this forum have reported that their emergency brake is stuck which would mean the rear brakes were dragging while they were driving. I suppose a quick check of that could be done with one of those hand held infrared thermometers that you can buy rather cheaply at harbor freight tools.

Check out this tread as well: http://forums.tdiclub.com/showthread.php?p=3695242

Step 1 take the rack off, that's eating a good 3-4mpg on the highway.
Step 2 wait for summer fuel
Step 3 stop hooning around.

The rack is probably the biggest thing jacking up your mileage. Although, seeing that you are in Cali, do you guys get winter fuel out there?

#1 You're not going to get the same mileage as you did with your 2000 TDi. More HP and more emissions with your 2012 that affect mileage.

#2 5k the motor is just starting to break in, you should start seeing an improvement from breaking in around 10k.

#3 You're on winter blend fuel. Wait till summer blends come back before you start to worry about mileage.

2011 JSW/DSG 4000mi. w/roof rack cross bars. Today's 72 mi. commute: 47.4 mpg This is in So Cal, winter fuel, certainly not fully broken in yet, tires at 36psi. and I do add 4 oz. of diesel kleen per fillup. But I too would be upset with your 30 mpg ....something is wrong with either your car or your driving style.

It's not even broken in yet!!! what is the recommended tire pressure for your car?

The single best thing you can do to improve fuel economy: use the brakes less. It's up to you to figure out how to do that without crashing into things.

Preservation of momentum.

Looking at your mpg history, I cannot believe by the numbers you're getting. Unless you're stuck in traffic doing 5-10 mph constantly round trip each day, I don't expect your TDI to put such a bad mpg (DSG or MT). Something is just not right. Your DPF must have clogged up, or something in your emission system not functioning normally. I'd get it checked right away at your dealer.

Does the fuel economy on your MFD agree with these numbers, or are these the numbers you're calculating yourself (or both)?

My mileage is not much better than the OP's. It is getting better as I am approaching 15,000.

Donald

JettersTDI said:

Looking at your mpg history, I cannot believe by the numbers you're getting. Unless you're stuck in traffic doing 5-10 mph constantly round trip each day, I don't expect your TDI to put such a bad mpg (DSG or MT). Something is just not right. Your DPF must have clogged up, or something in your emission system not functioning normally. I'd get it checked right away at your dealer.

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What I want to know is how you're getting such high numbers? Granted, my car is new but in order for me to break 39-40mpg, I have to really go easy on the right pedal and try not to exceed 75mph. I guess hyper milling isn't my thing...

I hope to at least hit 40mpg on my next fill. MFD is showing 43 at the moment and I know that's optimistic as true numbers are usually a mile or two less.

amstel78 said:

What I want to know is how you're getting such high numbers? Granted, my car is new but in order for me to break 39-40mpg, I have to really go easy on the right pedal and try not to exceed 75mph. I guess hyper milling isn't my thing...

I hope to at least hit 40mpg on my next fill. MFD is showing 43 at the moment and I know that's optimistic as true numbers are usually a mile or two less.

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From my everyday commute, I usually take it easy for the first 10 miles (shifting early) of my 50-mile commute. My average speed varies from 55-65mph on socal fwy, which is quite slow here. At 20 miles, my mfd reads around 50mpg and increases as I go further. I do a mix of coasting, mostly not in gear and in-gear when I want to decelerate. My target is to get above 50mpg on the mfd each trip. But it's impossible to reach that when you're doing city driving most of the time. So from my experience for achieving the best mpg is to at least drive 20 miles and conservatively ( doing less than the speed limit).

Thanks for the tips!

Will have to try that after 5k on the odometer... still breaking the car in. I drive 200 miles round trip a day with 90% of those miles on the highway. My guilty pleasure is passing people on hills and looking at their faces as I go by doing 80...

Some questions:

-How much throttle are you using when you accelerate (%)?
-How many rpms are you shifting at?
-What is your average speed for you daily commute?
-What is your speed on the highway when you aren't traffic bound?

Overall, I'd say 30 is pretty bad, you either have to be driving the snot out of it or something is broken. If I drive gingerly, I can get 50mpg. Normal driving I get around 45, though in the winter its about 42. My lowest tank ever was 40 I think. FWIW, I live in the DC area and traffic is pretty bad.

amstel78 said:

My guilty pleasure is passing people on hills and looking at their faces as I go by doing 80...

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And that's why you don't get 40+ MPG.

P0234 said:

Some questions:

-How much throttle are you using when you accelerate (%)?
-How many rpms are you shifting at?
-What is your average speed for you daily commute?
-What is your speed on the highway when you aren't traffic bound?

Overall, I'd say 30 is pretty bad, you either have to be driving the snot out of it or something is broken. If I drive gingerly, I can get 50mpg. Normal driving I get around 45, though in the winter its about 42. My lowest tank ever was 40 I think. FWIW, I live in the DC area and traffic is pretty bad.

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P0234,

Try some of the techniques outlined in this thread... I think you'll see a pretty substantial increase in fuel economy. I noticed 10-20% better on my typical commute around NoVA, but it takes a lot of concentration and looking ahead. Playing with the MPG display has turned into a game for me... better than speeding tickets!

To answer a few questions:

Yes, we live in SF, CA, but do not do THAT many hills.
The cocoa bean has a DSG transmission. I drive it in S mode around town some times, but I think my wife drives it in D. On the highway, it is all D.
I will remove the rack and see what difference it makes. I'm assuming it doesn't influence the around town mileage as much as it would the highway. But both seem low to me.
I will check out the other threads linked already.
Neither one of us drives like a bat out of hell, but my wife is from the Boston area and still drives like it sometimes.
My dealer sux (capitol in SJ), so I'm not sure I want to bring it to them for a diagnosis.

To clarify, I'm not trying to optimize my mileage, just trying to figure out why its 25% off of where most folks are at, which seems outside of the error bars.

Thanks and I'll update once I get some results (or not).

VeeDubTDI said:

And that's why you don't get 40+ MPG.

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Very true.

On the way to work today though, I made a conscious effort to drive like a nun on valium and was able to hit 50.1 mpg on the MFD. That's probably good for about 46-48 mpg in real numbers.

The 14 year old hot-rodder in me though was dying of boredom.

My wife even fell asleep in the passenger seat...

VeeDubTDI said:

Playing with the MPG display has turned into a game for me... better than speeding tickets!

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That is so true. It's a fun game to play with a big payoff comes time for your next fill-up. I try to beat my best mpg all the time. lol

amstel78 said:

Very true.

On the way to work today though, I made a conscious effort to drive like a nun on valium and was able to hit 50.1 mpg on the MFD. That's probably good for about 46-48 mpg in real numbers.

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Pretty soon it will be a habit, a good one, for driving at or below the posted limit. It makes me feel guilty everytime I step on it a bit going above 70mph.

JettersTDI said:

Pretty soon it will be a habit, a good one, for driving at or below the posted limit. It makes me feel guilty everytime I step on it a bit going above 70mph.

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PLEASE do not drive below the speed limit! Some folks like to get where they're going in a reasonable amount of time. If you wanted to drive like that you should have bought a Prius. Driving should be fun and if you're driving like an old woman while you have one eye on the MFD trying to maximize your MPG, you're not having fun and neither are the people in the line of cars behind you.

Keep right, pass left. Don't be a d-bag left lane hog and it's all good.

Your geographical area and the driver is at fault. Your 2000 TDI only got 40mpg, and your CR-TDI is getting about 10mpg less. This is about right from what I have read.

You need to change your driving habits more than anything.

^^^^What cleaver said. You got 20% lower fuel economy in your 2000 Tdi than was usual, and now you're getting 20% lower FE in your new Tdi. The only common element is you.

Drop the roof racks and pick up 2.5-3.x mpg overall, then learn to use your brakes less. There used to be a member here who said: "brakes are magical devices for turning fuel into brake dust." Think of that every time you want to use them, and watch your fuel economy rise significantly.

Edit: noticed you only have a virginal 5k on the clock! Don't read the advice above as "drive it easy". Use the accelerator pedal. Frankly, Tdi's don't really shine until properly broken in for 20k or more miles. Drive it like you stole it (lots of go pedal), just don't use so much stop pedal. Drive predictively. Look far ahead and plan your passing/lane changing better.

VeeDubTDI said:

Keep right, pass left. Don't be a d-bag left lane hog and it's all good.

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AMEN!!!

I can't stand it when people sit in the left lane thinking they own the damn road.

I was stationed in Germany for several years and learned to appreciate and apply the German modus of driving; courtesy and safety.

Very rarely do you find someone in the left lane of the Autobahn unless they're passing. If they're not, they're most likely American tourists.

Conrad -JSW said:

PLEASE do not drive below the speed limit! Some folks like to get where they're going in a reasonable amount of time. If you wanted to drive like that you should have bought a Prius. Driving should be fun and if you're driving like an old woman while you have one eye on the MFD trying to maximize your MPG, you're not having fun and neither are the people in the line of cars behind you.

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Or at the very least, stay well in the right lane. It's the imbeciles doing 60 in a 75 riding the left lane that's a problem.

I never understood why it's so hard for people in this country to comprehend. Drive right; pass left. Once you pass, move back over to the right. It's not rocket science.

amstel78 said:

Or at the very least, stay well in the right lane. It's the imbeciles doing 60 in a 75 riding the left lane that's a problem.

I never understood why it's so hard for people in this country to comprehend. Drive right; pass left. Once you pass, move back over to the right. It's not rocket science.

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As soon as they send that all important text message, then they'll move over.

Conrad -JSW said:

PLEASE do not drive below the speed limit! Some folks like to get where they're going in a reasonable amount of time. If you wanted to drive like that you should have bought a Prius. Driving should be fun and if you're driving like an old woman while you have one eye on the MFD trying to maximize your MPG, you're not having fun and neither are the people in the line of cars behind you.

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Well, to each his own. I don't worry about what people think. And please don't tell me what I should or shouldn't drive. I always put more than enough time to where my destination is so I don't have to worry about speeding. If you're one of those speed-demon, then more power to you. Plus, of course I'm not one who stays in the left lane to block the traffic. I know where my place is, so thanks for pointing that out.

Conrad -JSW said:

As soon as they send that all important text message, then they'll move over.

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How do you know? You must be one of the guilty one's out there?