MPG Underperformance

Discussion in 'VW Jetta hybrid forum' started by Bossless, Aug 3, 2014.

  1. Bossless

    Bossless Member

    I contacted EPA who contacted VW. Here is what VW said: " The Calibration flash shouldn’t have any effect on the vehicle during operation and the field fix in general should not have caused 4mpg loss if performed properly."

    My response to EPA: "I understand that VW is saying that this modification to the transmission should not affect FE, but shouldn’t a retest with a modified version of the car be conducted to certify that it doesn’t? After all, the car is different from the car I bought, and it is getting less milage after the modification."
  2. Eddyx

    Eddyx New Member

    Sorry but as of now I do not own a Jetta Hybrid, I am thinking of replacing my 07 GTI with a Jetta Hybrid. I have been driving a Prius, 2007 and now a 2010) for about 7 years. My 2010 has 109K miles and still returns 48+ mpg, I am not bashing the jetta hybrid, just letting you know that hybrids will last and return good MPG throughout their life. Now to my point, you cannot drive a hybrid like a regular car and get high mileage.
    I am not saying that you have to hypermile but as others have said you have to be aware of how you drive. The only way to increase MPG is by utilizing the electric motor and to do that you have to keep the battery pack charged. This means coasting or light braking when coming to a stop, on the freeway if the cars in front of you are slowing/stopping take your foot off the gas the car will slow and charge the batteries. If you live in a area where there are hills, try coasting a bit on downgrades. When I turn into my neighborhood I take my foot off the gas then lightly depress the pedal and I can go 30 mph on electric only the rest of the way home (about 1.5 miles). It will eventually become second nature, I still accelerate from stop lights, go around slow cars on the freeway mumbling " I drive a Prius.. ". High MPG can be achieved with little effort. I did try hypermiling and was able to return 52mpg and decided it was not worth the effort. Good luck.
  3. I800C0LLECT

    I800C0LLECT Member


    Not that they're wrong in this instance but that was exactly what happened to myself when it took me 3 visits to get our Passat Bluetooth module updated.

    I forced them to look up the tsb and they finally found it and didn't understand why the computer didn't find that to begin with.

    I hope you get this resolved and can post back the fix
  4. Bossless

    Bossless Member

    Here is the latest on my saga of trying to get my mpg restored.

    After the recall was redone, I did not immediately notice any mpg improvement, but after a few weeks of driving the fuel efficiency loss dropped from 9% to 4%. At that point VW took the car to their test facility where they test and certify FE for EPA. (They gave me a nice Passat loaner for almost a month while they had my car.) The results of the test on my car were: 43/46/44. The EPA specs are: 42/48/45 (city/hway/comb.) Now that I have gotten the car back and driven it for 219 miles my combined mpg is 46.8. Part of that better milage is due to the fact that the weather is cooler and I have not used any AC. However, my conclusion is that the first recall mod was not performed properly. Right now I am happy again but will see how it goes after I drive it more miles under more varied conditions.
  5. I800C0LLECT

    I800C0LLECT Member

    Really glad to hear the news. I wonder what was done wrong?
  6. Bossless

    Bossless Member

    Don't know exactly what was done wrong. I just know that the milage improved after the recall was redone by a second dealer with a VW corporate rep present. It wasn't immediate but took a few weeks to get within one mpg of what I was getting before the initial recall mod. I was getting 45 mpg (6630 miles) combined average before the first recall. After the recall, milage dropped to 41 mpg (5824 miles). After the recall was redone the milage improved to 44 mpg as confirmed by VW test facility. I haven't driven enough to verify that yet, but at 246 miles I am at 46.7 mpg. This is encouraging but has not included any AC use or interstate driving at this point. Time and milage will tell.

    Here are some quotes from the shop manual for this transmission that shows how it might be possible for errors to have been made. "Fill transmission with exactly 1.9L (no more no less) of fluid." "If the level of oil/fluid is too high or too low, the function of the gearbox will be impaired." "The oil level in the gearbox cannot be checked." (The first dealer that did the recall told me he checked the fluid level after I complained about milage.)

    The recall instructions calls for the gearbox to be completely drained and the residual fluid to be suctioned out before adding 1.9L of fluid. Detailed instructions and special tools were provided or prepared for this procedure. The high voltage system was de-energized for this procedure. As part of this campaign, only the gearbox control unit was to be reprogrammed.
  7. I800C0LLECT

    I800C0LLECT Member

    Ah....parasitic loss in that scenario does make sense. That's crazy. I imagine others might have similar issues with this recall if mechanics don't pay attention to detail.
  8. Bossless

    Bossless Member

    Yeah, this procedure was never intended to be done in the field on a routine basis since there is no maintenance schedule to ever change the transmission fluid. It took a lot of perseverance to get this reconciled. Lucky I had good mpg records before and after the recall and the dealer testing backed up my claim. Also note that VW accepts that highway milage as facility tested can run 2 mpg lower than the advertised spec.
  9. tomo366

    tomo366 Member

    Mine is gone I sold it last week......so my Hybrid Experiment is over......Lifetime average over 37,000 miles was 37.9.....best ever was 46
  10. Bossless

    Bossless Member

    After 548 miles my average is now 44.4. That includes some limited access highway driving and some AC use (we are having a winter heat wave).
    Last edited: Mar 12, 2015
  11. Thomas Smith

    Thomas Smith Member

    I just purchased my 2013 Jetta Hybrid SE two weeks ago. Actually, it's my wife's car but I end up driving it more than she does. It has 18,991 miles on the clock and is due for the 20k
    maintenance pretty soon. The dealer we bought it from put in a full tank of gas but I fear that they put in regular gas since the gas mileage so far has been less than stellar. According to the
    on board computer only 25.9 mpg. I just put in some Premium gasoline yesterday and reset the computer to start out fresh with it's calculations. I will also check the mileage manually at the
    next fill up. The computer right now shows an average of 30.6 mpg. Better than 25.9 but still not very good for a Hybrid vehicle which I have been driving like a grandma on her way to a
    church social since we got the car just to see what kind of mileage we could get. Well, so far I am not impressed. Will take it in for service next week and asked them to see if there is any
    reason for the lousy mileage.
  12. RC_newowner

    RC_newowner New Member

    Thomas,

    My onboard computer usually reads much lower than my hand calculated mileage. I only trust my calculations over many fill-ups, as I go to different pumps and different gas stations, although I tend to buy the same brand. You can see my mileage over the last 10,000 miles (7 months) in the real world mileage thread.
  13. Thomas Smith

    Thomas Smith Member

    Well, my Real world Mileage over the last 2 months has been very consistent between 37.1 and 38.4 mpg. That is with about 60% city and 40% highway driving. Keeping in mind it has been a SUPER COLD Winter
    here in Indiana. Today it was Minus 6 degrees with wind chill to minus 30 degrees. So I am hoping that once the weather warms up a bit that the car will actually do averages in the 40+ range. Yes, the MFD is pretty useless
    when it comes to calculating mileage. I have been manually calculating the mileage and going to the same Gas Station each time. So for now my average is between 37 and 38 mpg which isn't what I was hoping for but still
    a lot better than the vehicle I traded in. (2013 Nissan Altima 2.5) I was rated at 27 city and 37 Highway and I got 24 mpg average and never got more than 30mpg on the highway on a long trip to Florida.
  14. DMcDonald

    DMcDonald Member

    Well, my past couple tanks have been in the mid-upper 30s mpg. It has been quite a winter - very cold and snowy. Spring is around the corner, though. Have actually had temps above freezing lately, upper 50s today. On my commutes, the MFI has been reading in the mid to upper 40s mpg again. Even with snow tires on. It's nice to see the good mpgs coming back. Can't wait to get the snow tires off, a rite of Spring!
    Thomas Smith likes this.
  15. Thomas Smith

    Thomas Smith Member

    My last couple of tanks have been in the 33 -34 mpg range. However today when I filled up the mpgs were right at 41. It's been in the 40's and low 50's for the last 4 days so I believe the slightly warmer weather
    definitely is helping a lot. It never gets this cold in Germany as it does here in Indiana. Actually, it never got this cold here either until the last couple of winters. Hoping for winter to be over soon but they already
    said that starting next week the temps will drop down once again to below normal temperatures. Great.
  16. Bossless

    Bossless Member

    I have now driven 2849 miles including interstate driving with some AC. My average is 44.3. My conclusion is that the Jetta Hybrid does not come close to the highway spec of 48 mpg if you drive around 70mph. You might be able to achieve highway spec if you drive around 50 mph. City driving will achieve the 42 mpg spec and even a little better if you drive very carefully. Consequently, with a mix of driving I am running about 1 mpg below the 45 mpg spec. This is by driving with gas economy in mind, but not to the extreme. However, to really enjoy this car, I sometimes drive aggressively utilizing the turbo charger and electric motor to the max. Also, I am fortunate that most of my short trips involve county driving with speed limits of 55 and 45 mpg.
  17. jrpenberthy

    jrpenberthy New Member

  18. Bossless

    Bossless Member

    I don't think there is enough leverage to accomplish anything. If you are still under warranty you can file a claim with the BBB.
  19. I800C0LLECT

    I800C0LLECT Member

    Well the mpg cycle is very specific. The shenanigans you're concerned about are mostly due to media attention right now.

    Sadly, the cycle used to achieve mpg estimates has nothing to do with real world driving. It's a very specific routine that even controls acceleration.

    Couple of things in VW's favor for testing mileage(I may be completely wrong)...It's completed on a flat surface. They tape up all breaks in the surface of the vehicle. Probably drop the passenger side mirror. Use 100% gasoline...no ethanol. Etc. Why are they so invested in cheating? That's getting into the business side with cafe and fleet averages.

    They look for every advantage they can find. If they can complete it on a dyno without having to worry about aerodynamics I'm sure they'd do that too. The problem with the EPA and test cycles is that engineers are forced to design the car for that test independently of real world driving. However, the media does a terrible job bringing that forward. That's why diesels under perform and gasoline typically over perform.

    IF we all drive according to that cycle we'd achieve the same mpg.
  20. Raz

    Raz New Member

    I got mine in April 15 my average is about 43. I do have a lead foot so worst was 36 best 55.2. I drive about 37 mi one way and I'd say 50/50 and it hits 80 mph everyday. Overall I'm impressed with this hidden gem!!!

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