Very disappointing ~33 mpg

[garybeck]

Ok I've had my 2012 Jetta TDI manual-transmission Sportwagen that was "tweaked" by VW for over a year now. I've been monitoring the fuel efficiency both manually and with the electronics on board. they are both reporting consistently in the low-mid 30s. this is extremely disappointing. is this typical? I have two friends with the exact same car. one says he is getting over 40 regularly. the other says he is also in the mid 30s.

yes i have a ski rack. but that can't possibly be explaining all this. I had a ski rack on my 2004 TDI Wagon and I got mid to high 40s on that one.

I have just heard about the water in the intercooler issue for the first time and wondering if this could affect fuel mileage? i know my car sat for several months while it was being serviced for the emissions thingy. and also wondering if checking/draining/fixing that would be covered under my supposedly awesome warranty that VW was forced to put on all the cars that were serviced for the emissions fraud case. I was told the entire engine and fuel system are 100% covered.

anyway I'm just trying to figure out if there is something wrong with my car or if this is what I should expect on this model. I would not have purchased this car if I knew it was going to get 33 mpg.

thanks
gary in vermont

 

[alext91]

I picked up a manual JSW this year and I also agree that the mileage is disappointing. The car usually indicates somewhere between 38-42mpg but my hand calculations ( I almost always use the same fuel station) usually show 34-38mpg. Definitely disappointing, especially if you've had one of the older cars. My wife's 2015 regularly gets 46-50, sometimes I wish I had gone for an EA288 car instead, but I really like my JSW.

Sent from my SM-G960U using Tapatalk

 

[PRY4SNO]

I think a lot of it has to do with your commute and driving style.


I do mostly highway at ~2k rpm in 6th on cruise and have consistently returned 6L/100km (39mpg). A bit better in the summer, a bit worse in the winter. And a bit better before the fix, 50-100km per tank on average.

 

[garybeck]

I think a lot of it has to do with your commute and driving style..

it is true that those things affect your mileage. however I am a very passive driver, I do not slam on the gas ever, and i just checked it when I was traveling on straight highway for an extended period of time and it was 33.9. it should be higher for a TDI. unless they had to really tweak something serious to get it to comply with emissions standards.

the main reason I got this car was for fuel efficiency. if this the best it can do i'm going to start thinking about a different vehicle.

 

[tjg]

That's definitely out of the ordinary... those numbers are what I was getting when I was having issues with my catalytic converter. How often does your car go into regen?

 

[06bluebeetletdi]

How far do you drive a day? City or highway? Ski rack as in cross bars only or something more? My beetle is consistent 36-37 mpg, I drive 65 miles a day, about 60 miles of that at 70 mph.

 

[Pharcyde145]

I remember you posted something similar this spring, back in May. Did you ever look into the rear brakes to see if they were dragging? Or check/change your fuel filter during any service? What size tires/wheels are you running? When's the last time you had an alignment? How much weight do you carry on a consistent basis in the vehicle? There are so many factors that can/will affect mpg's.

If you're driving rte's 100, 108, 14, 15, 16 or 2 in VT you should be getting between 34-42 mpg (the higher end if you're light on the throttle through the hills and use your momentum wisely). Better if you're driving on 89 at the speed limit, over 70 you'll see it start to begin to dip with the "fix" tune.

I've put 34K on my 2011 6spd and have averaged 37.8mpg and burned 782 gallons of USLD with no additives. I drive 60/40 (hwy/city) with some long road trips from SLC to PDX, Mammoth Lakes, etc. On the longer trips I'll get 41-44mpg hand calculated, but because of the day to day stop light/stop sign, school zone's & buses my lifetime average is still 37.8mpg.

If you really want to see higher numbers, keep a fuel log to use for hand calculations (gallons-filled/miles driven) and to make notes about each tank like the primary driving conditions for that tank, be attentive to scheduled maintenance (running gear, alignments, filter changes etc) and go through your vehicle during each service or have someone you trust do so. All this info can help you identify both an optimal driving style for your vehicle and allow the vehicle to run as efficiently/properly as possible. The CJAA is not an ALH, but it still is a great motor.

 

[CheapBastard]

I get 30 with around 90% city driving, I was also disappointed but still an upgrade from the 23mpg my TSI was giving me

 

[PRY4SNO]

If you really want to see higher numbers, keep a fuel log to use for hand calculations (gallons-filled/miles driven) and to make notes about each tank like the primary driving conditions for that tank, be attentive to scheduled maintenance (running gear, alignments, filter changes etc) and go through your vehicle during each service or have someone you trust do so. All this info can help you identify both an optimal driving style for your vehicle and allow the vehicle to run as efficiently/properly as possible. The CJAA is not an ALH, but it still is a great motor.

Fuelly is another good way to do this without having to keep physical notes.

 

[JELLOWSUBMARINE]

I get 30 with around 90% city driving, I was also disappointed but still an upgrade from the 23mpg my TSI was giving me

At least here in my part of Ca diesel fuel price are more stable than gas, and regular prices can and have run the same $. +-. My Subaru cost the same per mile to drive (fuel $) on mixed driving but the TDI is much better on long drives where it shines. Unfortunately some have seen the lie-o-meter read 50 mpg on a certain occasions and kind of messed with some expectations.

Fuelly.com is ez and gives a real mpg. From what Ive seen 37-38 mixed mpg should be expected, maybe 40+ freeway/flat. Several more with delete/tune.

I think I remember your earlier post also. Didnt you have an occasional brake type pull/tug?

 

[icrashcars]

Im also disappointed in my fuel mileage. I do not accelerate hard, but I do drive 80mph on the highway. I am averaging about 35 mpg.

My work car, a 2017 honda civic, averages 38...and regular gas is $1 less per gallon.

 

[JELLOWSUBMARINE]

Im also disappointed in my fuel mileage. I do not accelerate hard, but I do drive 80mph on the highway. I am averaging about 35 mpg.

What year is your JSW? I have heard the 6th is much taller on early years. My 5th @ 65mph is 2k rpm. 6th gear almost seems too much? I'm running a few tanks checking mpg only using 5th on freeway (50/50ish). It appears no real mpg difference. I wonder if the regens are countering mpg with 6th gear "dogging"?

 

[Shoveltrev]

Replace your thermostat

 

[gt40girl]

Replace your thermostat

Curious because my non buyback 2014 bug convertible got 36 mpg with the top down and 45+ with it up. Turned him in...regretted it and lots of other factors and purchased a “fixed” 2014 Jetta TDI. which barley gets 36 mpg. HOWEVER, I get the coolant smell on cold days! So, what does replacing the thermostat do to improve mileage.

 

[icrashcars]

what year is your jsw? I have heard the 6th is much taller on early years. My 5th @ 65mph is 2k rpm. 6th gear almost seems too much? I'm running a few tanks checking mpg only using 5th on freeway (50/50ish). It appears no real mpg difference. I wonder if the regens are countering mpg with 6th gear "dogging"?

2011 6mt

 

[IndigoBlueWagon]

Couple things: First, emissions controlled TDIs use a lot more fuel on warm-up to help get the emissions hardware up to temperature quickly. If you drive shorter distances (say, less than 10 miles before shut down), your mileage is going to suffer. Also true in colder weather, to a greater extent than the older cars. And a faulty thermostat will absolutely cause an increase fuel consumption, although I don't think thermostat failures are that common on newer cars. Or at all, for that matter.

We've heard of cars that have DPFs that are near the end of their lives (or are cracked) that are causing more frequent regens, which of course uses fuel. But reading this thread it sounds like a lot of people are experiencing FE in the 30s, and I doubt all of them have failed DPFs.

My '12 Golf Manual would dip in the 30s during short trips in colder weather. My average FE in my '15 GSW is around 44, but those are mostly highway miles.

 

[Pharcyde145]

The thermostat failing in the open position would make sense for having higher fuel consumption, since it's always circulating cold coolant tricking the ECU to think it needs to add a bit more fuel to warm up properly, just like IBW mentioned.

He's also right that the possibility of all our thermostats needing to be replaced due to excess consumption caused by a faulty thermostat is quite slim. It's a good thing to have on the list of possibile failure points, but not what I'd list near the top until after I did some trouble shooting in other areas first.

Judging from the regen cycles I've experienced with my '11 it'd have to be in regen mode constantly to be burning that much fuel. But the fans should be the canary in the coal mine, since they'd be running constantly also, and wouldn't allow me to remain indifferent to the issue.

These cars were built for endurance and seem to respond well to long distances and constant use, which coincidentally is the best formula to apply other refined driving habits to truly see a positive difference in FE/MPG's. Everyone's needs and commute is different, but constant short trip intervals combined with not allowing the vehicle to fully warm up are a recipe for poor performance/efficiency with the TDI platform (and most ICE applications for that matter).

 

[Shoveltrev]

a recent thread on this site told the story of repeated dpf failures too frequent of regens and poor mileage that was finally solved by replace a weak thermostat that was opening too early . my 12 jsw i was monitering the coolant temp with the vag and my stat was opening at 160 . at this time the dash gauge was rock solid in the middle and my average fe was 34 mpg. aafter replacing the stat and coolant which is a good idea anyway considering how long somne of these were in storage my fe has climbed to 38.5 . all hand calculated

 

[Shoveltrev]

aand it now opens approximately 192 degrees

 

[JELLOWSUBMARINE]

a recent thread on this site told the story of repeated dpf failures too frequent of regens and poor mileage that was finally solved by replace a weak thermostat that was opening too early . my 12 jsw i was monitering the coolant temp with the vag and my stat was opening at 160 d

aand it now opens approximately 192 degrees

Great point,

I wonder how many open too soon, never going in closed loop in these colder temps?

I thinkshoveltrev may be onto something.

Ive been watching my center vent temps closely from warm up. @55* ambient outside temp/cold start up, I can say my 11' runs great. It seems to warm up slower than a gas engine but up to temp if gone several blocks/stops and jumping on the freeway. Or a couple miles around town.

The temps at the center vent, full hot setting, fan 1st speed.
As the car/dash temp. climbs from cold, the center vent gauge temp reads apx 10-15* below indicated engine temp. (on dash)... Heres what I found interesting... When the center vent hit 170*, the dash simaltainiusly hit 190*. At that point the center vent temp. drops to100* and fluctuats mostly back upward. The dash holds @190*. This is telling me the thermostat is opening properly, taking on cold radiator water and closed properly. BTW the same settings gave a constant 155* out the vent when the thermostat was fully warmed.

Ive seen alot of cold heater chatter on these TDIs lately. They have pointed toward a cooling system gelling up and clogging heater core along with thermostat malfuntioning (holding open). Flushed, replaced thermostat & off and running great... Worth looking at.

Hope this helps

 

[crashtested]

Averaging 37.8 over the last 14 months. Mon-Fri is a 140km (87mi) highway drive to work and back. Weekends are usually a couple rips around town or out on the highway off to the beach which is just about the same distance to-from work.


Better then our 2010 GSW ever was.



Tape of the tape below.

 

[ksing44]

My average for 2019 is only 34.6 mpg in my 2010 Golf 6-speed manual. I started off much better when I first had the car, but I drive faster now (~80 mph), the frequency of my long commute has decreased, and I think the fix also had an impact of ~2-3 mpg.

on Flickr

 

[MattRabbit]

My wife's Beetle has been getting between 30-32 mpg on her commute. If we take it for a long drive it'll get around 40. Her commute has a lot of stop and go (mostly stop), but if you can give it a good run, it'll return good numbers.

My 2015 Golf mk7 gets around 40 in mixed driving. I've gotten as high as 45 and as low as 37.

 

[lostru]

All of the above is great information to look at. One more thing to check is your alignment. I gained 2 MPG after getting it done by a very competent repair facility. If you have a way to check and chart your ECT, this would be something that is easily done and has big returns if you identify an issue. Also, what are your beginning temps before your first drive of the day?

 

[KITEWAGON]

The ski rack is probably worth 2-3 mpg and other than that your mileage matches mine in the colder weather. I have a shorter commute which is the main issue. If I drive 50 miles at 55 mpg I can easily get up into the mid-40's and have even seen 50 mpg reported on a longer drive under very good conditions.

The winter fuel and colder temps seems to be a 3-4 mpg loss as well. The ID parts winter front should help slightly. I'm noticing my car get up to temperature more quickly on my P3 gauge which I keep on coolant temperature 99% of the time.

 

[virtualpj]

The ID parts winter front should help slightly.

Know anyone that carries something similar now that ID Parts has discontinued these?

 

[Pharcyde145]

Can't say that I've seen any.

The lower grill should pop out similar to the fog light covers on most Golf's, if you have a GTI or R front bumper it might be more difficult requiring you to remove the front bumper. Since you have a JSW I'm guess you have the generic front bumper with no fogs found on Golfs. Shouldn't be too hard to pop it out and create a template of the backside of the grill out of cardboard.

Then you can either wrap that cardboard in 3-5mm plastic like a contractors bag or find some other water resistant material and lay the template over it. A lot of folks I know with 3/4 and 1 ton diesels block their grill out on the cheap and easy like this. Really shouldn't take long, change the look or cost much if you think it out.

 

[RoundHouse]

Mrs roundhouse has had a 00 beetle five speed for years and it’s never gotten over 40 on the interstate and
Usually around 35-36 in town

My 01 golf five speed got 44 every tank no matter how or where you drove it
Needed a larger vehicle , 12 yr old child had juvenile arthritis and had to have room to stretch out on trips longer than 1/2 hour

sold the golf and got a 06 4wd expedition that gets 11.5 in town and 17 on long interstate trips.
That bites after getting used to 44 in the golf

 

[IndigoBlueWagon]

Thought of this thread today. Drove my 335d to Maine and back today for Holiday shopping at L.L. Bean, an annual outing. Round trip is just over 300 miles. Filled before I left, cluster now shows 32.6 MPG. It usually reads 2-3 MPG low on this car, so I expect I got 33-34 MPG. All highway, but a fair amount of it was at 80-90 MPH. Same MPG as the OP is complaining about, but in a car with a 3 liter six and twice the power of the TDI. My 335d is tuned, but all emissions are intact. Seems that something has to be wrong with people getting that poor FE on the TDIs.

Also, on the drive up outside temps were in the single digits, low 30s on the way back. So we had weather working against good FE, too.

 

[vincej]

I figure the 2014 post fix burns 1 liter more per 100kms over the 2013 before fix, which I had returned. So I've gone from an average of about 5.5L/100km to an average of 6.5L/100km.
1L/km, about 3 MPG?
Big time difference though if jumping from 80km/Hr(50Mph) to 110km/Hr(68Mph). They like 1800 RPM.