fuel mileage questions

DivineChaos

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Jul 27, 2019
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mk6 jetta sportwagen tdi
so first of all i just got a "fixed" 11 jetta sportwagen tdi 54k miles and so far i love it. Both my dad and i got one 78k miles. Mine came from NY ans his FL. Only difference is color and he has a moon roof. I am trying to figure out why im getting less mileage on the highway at the same speeds. I get about 4 mpg less than him on the same route. im talking 6 hour drives at 68mph average both using a/c. I replaced the air filter and that seemed help some. And this is with running 40 psi in tires. Mine does make the annoying eeee-errrrr-errrrrr-eeeee noise from the exhaust flap. any help is appreciated guys. After warranty out its getting tun an propane injection.
 

PRY4SNO

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May 15, 2016
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Edmonton, AB
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2010 GSW 6 speed
Does your dad's have the emissions modifications?

That's pretty high tire pressure if you're not towing or carrying a lot of gear, could lead to uneven/premature tire wear. Consult the door placard for more info, I believe 35 or 36 psi is what's recommended.

If you've got an issue with the exhaust pathway that could be an issue worth investigating. The extended emissions warranty would certainly cover anything related to the exhaust flap, if that is indeed an issue.

All else being equal between the two cars, and no mechanical faults to blame it would likely have to do with driving style. From what I've read on the hypermiling threads it's best to accelerate up to speed briskly, especially between 2-3k rpm, shifting at 3000 rpm.
 

JELLOWSUBMARINE

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2011 JSW 2008 E350 6.0
First of all congrates, these are great cars. I bought an 11 in Feb and love it. Where either of your cars CPO ?(dealer Certified Previous Owned). The exhaust flap is covered either way under emmisions warrenty.

Heres a new owners info thread you may want to contribute.
forums.tdiclub.com/showthread.php?t=496462

If your (non original) tires have higher pressure than o.e. tires, thats what you should run. Some shops set @ door specs simply to be C.Y.A. compliant.

I think PRY4SNO has something about accelerating quickly and higher rpm. I just got back from a trip in the Ca. Coast hills with alot of twisties and low gear pulls. I thought the mpg would be sh!t but I got the best yet. Another conversation/thread here is about correcting the acual mpg reading on the dash (lie-o-meter)��. If you want real mpg figures fuelly.com is great.

As soon as I can, I would love to delete and tune. With the manual it should go for ever
 

JELLOWSUBMARINE

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my mpg went up as I ran new fuel through. These CPO's have had the same partial tank sitting through diesel gate for up to 2+ years.
 

DivineChaos

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Jul 27, 2019
Location
gets cold here
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mk6 jetta sportwagen tdi
Does your dad's have the emissions modifications?

That's pretty high tire pressure if you're not towing or carrying a lot of gear, could lead to uneven/premature tire wear. Consult the door placard for more info, I believe 35 or 36 psi is what's recommended.

If you've got an issue with the exhaust pathway that could be an issue worth investigating. The extended emissions warranty would certainly cover anything related to the exhaust flap, if that is indeed an issue.

All else being equal between the two cars, and no mechanical faults to blame it would likely have to do with driving style. From what I've read on the hypermiling threads it's best to accelerate up to speed briskly, especially between 2-3k rpm, shifting at 3000 rpm.
So maybe it isn't opening up all the way? I also hear some other electric motor flipping something under the hood after I shut down. Does actuated it 3 times. They are a eco tire. Was just seeing if it changed mileage. It is regularly loaded with 500lbs of stuff in the back. So have the dealer check exhaust flap for correct opperation?
 

DivineChaos

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Jul 27, 2019
Location
gets cold here
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mk6 jetta sportwagen tdi
First of all congrates, these are great cars. I bought an 11 in Feb and love it. Where either of your cars CPO ?(dealer Certified Previous Owned). The exhaust flap is covered either way under emmisions warrenty.

Heres a new owners info thread you may want to contribute.
forums.tdiclub.com/showthread.php?t=496462

If your (non original) tires have higher pressure than o.e. tires, thats what you should run. Some shops set @ door specs simply to be C.Y.A. compliant.

I think PRY4SNO has something about accelerating quickly and higher rpm. I just got back from a trip in the Ca. Coast hills with alot of twisties and low gear pulls. I thought the mpg would be sh!t but I got the best yet. Another conversation/thread here is about correcting the acual mpg reading on the dash (lie-o-meter)��. If you want real mpg figures fuelly.com is great.

As soon as I can, I would love to delete and tune. With the manual it should go for ever
Unfortunately neither were cpo. I will definitely be deleting after warranty is up. So the displayed mpg is innacurate? By how bad? So maybe my gauge is just off and mileage is alright? Almost all the station's here sell b10. I did "accidentally" fill up with red fuel. In my defence it was a farmer's town and it was all nontaxed. And I was about empty.
 

PRY4SNO

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Edmonton, AB
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2010 GSW 6 speed
Pretty sure you're hearing fuel pumps after you shut off the key.

Never had that issue, so can't say other than search around more to get a better idea. If you don't have a MIL you'll have to pay a diagnostic fee.

500 lbs of stuff in the back regularly is a lot. Be prepared to upgrade your suspension at some point. Finally did mine (200k miles) and life improved remarkably.
 

DivineChaos

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mk6 jetta sportwagen tdi
ok, so aster i did a hard reset of the ecu. (disconnecting battery for hour) And after resetting all the lights that came on. (man was that a pain) Would you believe the check engine light came on. When checking the code it listed as egr, low flow. i noticed when driving the dpf light came on. So i ran at high speed till it was done with the cycle. after the almost 15 min cycle my mpg returned to almost where it should be. around 40mpg. When i brought it to the dealer i specified what i did and the mileages it was and is now getting.
They had it for maybe 20 minutes. Stated that the dpf needs replacement and that they are over a month backed up waiting on filters from corporate. Also saying how there is almost 100 cars ahead of mine also waiting on dpf replacement.
I left more confused so i called the service tech manager. Upon finding out the sales staff lied through hes teeth to me i was furious. He stated the dpf was replaced as part of the "fix". He clarified that it is part 2 of the recall work. And apologized for the sales staff dishonesty. that unfortunately it is "all too common".
I asked him about my radio. (because it didnt work and was replaced before purchase) He said nothing in my cars file stated the radio was replaced, so either the salesman did it himself or a tech did it under the radar. Being i get a radio communications error and that it was never transferred with sirus, i presume the first.
 

DivineChaos

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mk6 jetta sportwagen tdi
So i delved deep into the ecm flash as part of the fix. Because the nox level was 40x the limit the cars already produced almost no soot. for those of us who didnt know the basis of diesel combustion. The hotter the combustion the less soot and the more nox, the cooler it is the more soot and less nox. So what they did it add a minuscule amount if fuel to combustion to lower the temp thus reducing nox to safe and legal levels. Doing that lowered performance and fuel economy. this produced more soot and halves the life of the filter. Also causing more frequent regens and poorer mpg. So where as the dpf would last 90k before, it will last only 40k now. Hense why the 4 year 44k mile warranty, and why dpf replacement is part 2 of the emissions fix here in america. The ash will build up faster within the dpf. For those who are in emmisions states, one can have ash in the dpf washed out. it does require removal. for those of us who are not in emissions states. I implore you to delete and tune your tdi after the extended warranty expires and hold on to your dpf. I will be adding propane injection First to clean up the exhaust and improve economy/ power. then tuning and deleting my tdi at a later date.
 

PRY4SNO

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2010 GSW 6 speed
Be sure to post a thread about your propane injection build. Will be very interesting to follow.
 

DivineChaos

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mk6 jetta sportwagen tdi
Be sure to post a thread about your propane injection build. Will be very interesting to follow.
the kit is 230 that i saw, not including the high pressure hose. i plan on using 1lb tanks and putting multiple in the first under trunk storage. before the underhood regulator adding a fill location. so i can fill all the tanks from the front using a 15lb propane tank. This route i would not loose trunk space or my spare.
 

JELLOWSUBMARINE

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2011 JSW 2008 E350 6.0
Be sure to post a thread about your propane injection build. Will be very interesting to follow.
X's 2

This isnt my 1st diesel by any stretch but it is my 1st DPF. I love just about everything about the JSW. It is being used as a low use backup, to keep miles down on our new Subaru. Everything an overegulated Ca. emmision choked DPF TDI doesnt like. One more reason to bail from Ca. and delete.

That said, what, if any advantage/help would propane offer?
 

DivineChaos

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mk6 jetta sportwagen tdi
X's 2
This isnt my 1st diesel by any stretch but it is my 1st DPF. I love just about everything about the JSW. It is being used as a low use backup, to keep miles down on our new Subaru. Everything an overegulated Ca. emmision choked DPF TDI doesnt like. One more reason to bail from Ca. and delete.
That said, what, if any advantage/help would propane offer?

propane makes it possible for the engine to burn 99% of the injected diesel. This all but eliminates the soot. Key benefits: cleaner exhaust (extending dpf life), about 10% power and torque added. Increases mpg by up to 10 mpg. You can add propane without having to tune or delete.
But You can tune without deleting. Keeps the egr shut when above a temp, increases cold idle speed. with a dsg tune it adjusts shift points and increasess the torque limit. And dont listen to the ppl that say you need 50%+ lpg fumigation. They are using as a power adder.
If used for mileage a max of 30% is needed, which will make it last longer. Main reason i will be doing it will be for the cleaner exhaust, The "fix" halved the lives if our dpfs. Side benefit is mileage and power. depending on the mix will dictate if you break even or not.
 

turbobrick240

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2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
Propane is a waste of time and money on the commonrails. The diesel gets so finely atomized by the ultra high pressures that lpg does nothing to improve the burn.
 

DivineChaos

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mk6 jetta sportwagen tdi
Propane is a waste of time and money on the commonrails. The diesel gets so finely atomized by the ultra high pressures that lpg does nothing to improve the burn.
Have you tried it? Do you know this for a fact? Without the dpf. These will blow black. Will still improve efficiency. Even as little as it may be. Especially when I delete and flash.
 

ewdysar

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SoCal
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2014 JSW TDi 6m
I’ll have to side with turbobrick on this one. Because he raised a point that I have no personal experience, I turned to the interwebs. Of course, all of the companies selling propane injection systems think it’s a good idea, along with the magazines that those companies advertise in. Most made no mention of the differences between indirect injection diesels like my GM 6.5L TD Suburban and TDi technology, and there are considerable differences between the two. I did find an article from an aftermarket diesel company that I consider to be reputable. https://official.bankspower.com/tech_article/propane-the-diesel/
Their initial opinions about the standard propane injection claims sound correct to me, and sound similar to turbobrick’s position.

That said, people believe what they believe (confirmation bias) so maybe the only way to truly evaluate the idea is to do an installation and objectively measure the results. Short of that, I would go with whatever reasonably unbiased opinions you can find.

BTW, back in my Honda days, there were lots of go-fast mods that people swore by, that were easily debunked. But even when proven ineffective, the guys that had bought in, still believed.
 

kjclow

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2010 JSW TDI silver and black. 2017 Ram Ecodiesel dark red with brown and beige interior.
just a question for clarity. I thought only the 15s had two parts to the fix. My 10 JSW was a one and done. Although it has been back in for some adjustments.

Also, on fuel mileage, the dash reading has been known to be off by as much as 5% on individual tanks. Best to always do a pen and paper, or Fuelly, calculation to determine for yourself how much to trust the dash. I find mine to be off 1-2 mpg most of the time.
 
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DivineChaos

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mk6 jetta sportwagen tdi
just a question for clarity. I thought only the 15s had two parts to the fix. My 10 JSW was a one and done. Although it has been back in for some adjustments.

Also, on fuel mileage, the dash reading has been known to be off by as much as 5% on individual tanks. Best to always do a pen and paper, or Fuelly, calculation to determine for yourself how much to trust the dash. I find mine to be off 1-2 mpg most of the time.
just relaying what I had read. It never stated the years. Just stated all tdi's that fell under the emissions recall. Weather. Vw will send out a notice for the replacement or just hope the vehicle will be fine in till warranty expires and only replace them if they fail before warranty ends.. who knows. I will try to get another replacement before my warranty expires though.
 

DivineChaos

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I’ll have to side with turbobrick on this one. Because he raised a point that I have no personal experience, I turned to the interwebs. Of course, all of the companies selling propane injection systems think it’s a good idea, along with the magazines that those companies advertise in. Most made no mention of the differences between indirect injection diesels like my GM 6.5L TD Suburban and TDi technology, and there are considerable differences between the two. I did find an article from an aftermarket diesel company that I consider to be reputable. https://official.bankspower.com/tech_article/propane-the-diesel/
Their initial opinions about the standard propane injection claims sound correct to me, and sound similar to turbobrick’s position.

That said, people believe what they believe (confirmation bias) so maybe the only way to truly evaluate the idea is to do an installation and objectively measure the results. Short of that, I would go with whatever reasonably unbiased opinions you can find.

BTW, back in my Honda days, there were lots of go-fast mods that people swore by, that were easily debunked. But even when proven ineffective, the guys that had bought in, still believed.
so my money would be better spent on tune and delete?
 

turbobrick240

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Yes, your money is much better spent on a tune. The delete is a matter of choice. I had one done pre dieselgate and it more or less pushed me into selling the car back rather than get the emissions "fix". I'm also getting too old to have illegally modified cars. Any illegal modifications typically murder the resale value too, if that's a concern.
 

DivineChaos

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Yes, your money is much better spent on a tune. The delete is a matter of choice. I had one done pre dieselgate and it more or less pushed me into selling the car back rather than get the emissions "fix". I'm also getting too old to have illegally modified cars. Any illegal modifications typically murder the resale value too, if that's a concern.
I would probably keep the factory exhaust for a just in case scenario. We don't have emissions testing around here. Would a dealership notice a tune in the ecm? My dealership is not a highly rated one. Could always flash back to stock before going in.
 

kjclow

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I doubt many of the dealers would ever notice a tune written to the ECM. They may, however, overwrite that tune with a software update. Now removing the exhaust system should be fairly easy to notice.
 

Pharcyde145

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I agree with Kj that most dealership service tech's either won't notice or won't care about tuning software being loaded onto the ECU, especially in area's where emissions testing isn't required.

But be careful if you decide to go that route because if you do flash your ECU with a tune it will be indicated/recorded on the ECU that is has been re-tuned/flashed and that could lead VW to deny any and all emissions warranty work. It's similar to preforming work on any new car that would void the warranty because the vehicle's ECU will no longer operate under the values that VW reprogrammed it to, meaning it could lead to running conditions either not seen or anticipated for the motor since it was reprogrammed. Which even though it will make the car run better and usually boost your MPG's, it will open the door to VW potentially saying it will refuse to honor the warranty because the vehicle is no longer in compliance with the conditions of the warranty.

8asically if you're willing to absorb any emissions warranty related costs for the advantage of the tune, you'll be ok since it will all be your responsibility. If you are hoping to make maximum use of the warranty and hold VW responsible for emissions related costs, your safest bet is to NOT tune the vehicle until it is out of it's warranty period.

Another option would be to find an ECU from another identical model, send that to Malone or Kerma for a tune and swap the tuned ECU with he Factory ECU when you need to take the car in for any emission related service. This might prove to be more difficult since you will probably need VCDS at the very least to resolve any issues you might run into when swapping ECU's, but by going this route, even when the dealers plug into your vehicle there won't be any indication you have been running the vehicle with a tune. They will be able to see that the ECU is not original to the car, but that is an easier explanation (the previous one was fried etc.) to a dealer than asking them to ignore your tune, which they are not obligated to do.

I really want to tune and delete but SLC has emissions regulations (damn this smog) I need to abide by and as a current student I do not have enough disposable cash reserves to pay outright or to fix large ticket items myself so I'll let VW pay for any and all repairs until the warranty period expires.

At the end of the day its always interesting to see folks pursue their idea's, continue to evolve the knowledge around the TDI platforms and share their experiences with others. That's why we're all here right?
 
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DivineChaos

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mk6 jetta sportwagen tdi
That is absolutely not true. No diesel will "blow black" unless it is overfueling or is being starved for air. I very mild tune, especially on a CR, will produce no visible smoke at all. My mild tuned ALH doesn't smoke either.
sorry i should have said can. and most diesels without dpf will blow a puff of black when stepped on. which when tuned well should be the only time any black smoke comes out. Yes they can be tuned to roll coal, but i am not looking for that.
 

DivineChaos

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I agree with Kj that most dealership service tech's either won't notice or won't care about tuning software being loaded onto the ECU, especially in area's where emissions testing isn't required.

But be careful if you decide to go that route because if you do flash your ECU with a tune it will be indicated/recorded on the ECU that is has been re-tuned/flashed and that could lead VW to deny any and all emissions warranty work. It's similar to preforming work on any new car that would void the warranty because the vehicle's ECU will no longer operate under the values that VW reprogrammed it to, meaning it could lead to running conditions either not seen or anticipated for the motor since it was reprogrammed. Which even though it will make the car run better and usually boost your MPG's, it will open the door to VW potentially saying it will refuse to honor the warranty because the vehicle is no longer in compliance with the conditions of the warranty.

8asically if you're willing to absorb any emissions warranty related costs for the advantage of the tune, you'll be ok since it will all be your responsibility. If you are hoping to make maximum use of the warranty and hold VW responsible for emissions related costs, your safest bet is to NOT tune the vehicle until it is out of it's warranty period.

Another option would be to find an ECU from another identical model, send that to Malone or Kerma for a tune and swap the tuned ECU with he Factory ECU when you need to take the car in for any emission related service. This might prove to be more difficult since you will probably need VCDS at the very least to resolve any issues you might run into when swapping ECU's, but by going this route, even when the dealers plug into your vehicle there won't be any indication you have been running the vehicle with a tune. They will be able to see that the ECU is not original to the car, but that is an easier explanation (the previous one was fried etc.) to a dealer than asking them to ignore your tune, which they are not obligated to do.

I really want to tune and delete but SLC has emissions regulations (damn this smog) I need to abide by and as a current student I do not have enough disposable cash reserves to pay outright or to fix large ticket items myself so I'll let VW pay for any and all repairs until the warranty period expires.

At the end of the day its always interesting to see folks pursue their idea's, continue to evolve the knowledge around the TDI platforms and share their experiences with others. That's why we're all here right?
Does the ecu have to be programmed for the car if i got another one? with the vin.. or will it just plug in and work?
 

turbobrick240

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maine
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2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
you'd need an immobilizer delete on the tuned ecu. My feeling is that once you cowboy up for a tune, you accept the responsibility of being your own warranty. At least for the drivetrain components.
 
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