Over the past six months or so my fuel economy has been dropping, and I'm currently at the point that I'm starting to worry there may be some expensive maintenance in my future. 2013 TDI Lux, I'm the second owner. I'm at 145,200 miles, I perform oil changes every 7500 miles, new fuel filter installed every other oil change, air filter is cleaned regularly, transmission fluid was very recently changed, differential fluids have been changed out recently. The front tires are starting to get close to needing replacement, and the rear tires are almost brand new. The only known issues that it has are a timing chain cover oil leak (I keep up on adding oil between oil changes (usually about a quart)) and the transmission is starting to shift a bit funky (feels like it might be a torque converter issue). Up until six months ago I would regularly get 28 mpg going from work to home (about 200 foot elevation decrease) and 26 mpg going to work. With other little trips around town, my average combined fuel economy per tank was 26 mpg. I'm now getting a consistent 25 mpg both to and from work, with the per tank average down to about 24 mpg. Driving habits have not changed. Living in SoCal desert, so there's only one hill I go up to get to work. 84/16 split highway and city driving. I wondered if the increased heat and A/C usage might have played a part, but in the two years I've owned the Treg, she hasn't behaved this way in the past two summers. Any suggestions what might be going on that I should look into?
JumpinLegs
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Tezza1062
My 2009 Touareg Fuel and power fell off after 250 Km the engine light came on and the code came up found out that the inlet manifolds Flaps controller was going over the sensor got a replacement set of Flaps from the web as a kit, it was very cheap about 60$ found the replacement video on u tube took me about 5 hours and the manifolds had a lot of carbon build up in there the improvement was fantastic
Personal experience is that 3.5% difference in tyre height is too much.
Be very careful cleaning that MAF sensor, they damage extremely easily. Just take the sensor out and wipe it to see if it's got any residue on it. If it doesn't, leave it alone.
VW doesn't sell a replacement MAF sensor, you have to buy the whole thing and it's not cheap so if you do manage to wreck it by cleaning it get the Bosch part number off the actual sensor and buy that.
The sensor is held on with two FIVE point security Torx screws. A quick swipe with a hacksaw turns them into a flat blade screw.
How did the Liqui Moly cleaner go? Did the procedure you used to clean the EGR plate mean that your intake valves got a clean too?
I used Mr Muscle oven cleaner, same stuff but it's foamy and hangs on better and it's waaaay cheaper.
You could also check for a drippy fuel injector.
It seems to me that if you had a dodgy torque converter that you might be losing power through slippage. Have you rechecked the trans fluid level? As mentioned earlier, a trans fluid conditioner may help, I've had a good run with Lucas, but it won't help a crook torque converter obviously.
I managed to understand what you were saying about your tyre size and how you compensated in your MPG calculations.
If you were damaging your drivetrain, you'd know. The axle windup is very noticeable.
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I didn't end up cleaning the MAF sensor. Decided I didn't want to risk wrecking it accidentally as this is my only working vehicle currently. I did an oil change, fuel filter change, and Liqui Moly intake cleaner all on 6/18. I used Liqui Moly Engine Cleaner and Diesel Purge with the oil change and the fuel filter change. Liqui Moly intake cleaner seemed to work okay that first day (throttle response seemed a bit better), but that first tank after the service I got 22.3 mpg (calculated correctly), which was pretty abysmal for my Treg. I forgot to get the fuel economy from the subsequent tank, and then the most recent tank I got 24.08 mpg. I just sprayed two cans in upstream from the intake manifold, didn't end up taking off the throttle body/air mix flaps like in this video, I was barely upstream of here. I did just purchase a VCDS from ECS Tuning, so Saturday I'll see what codes pop up. I should be able to check the trans fluid level with the VCDS too, right?
Intake cleaner will not be effective enough to remove a build up of soot & oil. The inlet horn, idle control valve will most likely be the most affected more so than the actual manifold. The only option is to removal and scrape it clean. Its easy enough and costs nothing apart from a can of brake cleaner.
Negative.
Did you visually check for carbon buildup?
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Nitpicking, but diesels don't use an idle control valve
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I didn't visually check. I didn't have any extra gaskets to replace on the inlet horn, etc. should they not spring back like in the video I linked. I do plan on getting some of those gaskets and taking the inlet horn, etc. off to do a thorough cleaning.
How does one check transmission fluid level without performing a full transmission fluid flush?
How your amnesia bud? Or are you seriously asking how to do something you've already (allegedly) done?
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C'mon dude. I performed a fluid level check when I changed my transmission fluid. Per the instructions I followed, it was full when it stopped weeping out of the fill hole and the fluid was at the correct temperature. Now, since transmission fluid can't magically appear in the transmission after it's been sealed again, if I open that fill hole right now, if it's properly filled, it won't leak out. Also, if it's too low, it won't leak out because there won't be enough to make it out of the fill hole. So. Please. Without being condescending, explain how I can tell that I have the proper fluid level in my transmission without having to take the transmission fluid pan off and having to refill the transmission again.
If it doesn't weep out at temp you could always pump half a quart in and check again to see if it does. That'd tell you it was close...
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Thanks for a helpful comment. It seems silly that VCDS can't check the level, but oh well. I've got some extra trans fluid (I think) so I'll see if I can use VCDS to ensure the fluid is at temp then pump in a little extra.
it would just end up being one more sensor everyone would bitch about
You're correct its the inlet swirl flapper that gets bunged up reducing air flow & probably its ability to swirl the air!!
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Yes. The swirl flaps are unreliable pieces of trash
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You are assuming that there's even a level sensor installed (don't believe there is)
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Not having a level sensor installed seems like a bit of an oversight.
I don't know why someone hasn't invented the idea of two dipsticks to check oil levels with one for the engine and one for the gearbox.
Such devices, mounted in a tube in an easily accessible place such as under the hood/bonnet would make life so much more simple and, when correctly marked with the fluid levels, could even be engraved with how much oil/ATF to add if required.
Funny no one has thought of these simple devices.....
Such devices, mounted in a tube in an easily accessible place such as under the hood/bonnet would make life so much more simple and, when correctly marked with the fluid levels, could even be engraved with how much oil/ATF to add if required.
Funny no one has thought of these simple devices.....
I don't like wasting brain cells to revisit stuff that I asked previously when trying to help others diagnose crap.
I don't know or care what youtube video you used to do your service but here are some hints.
How To Change VW Touareg Transmission Fluid 2011-15 8-Speed 08C Aisin
Steps on how to change the VW Touareg transmission fluid on 2011-2017 8-speed automatic transmission applications. This transmission type is also referenced as the 08C Aisin TR-80SD or TR-82SD transmission. Blauparts is here to help. We discuss what type of ATF should be use in the VW Touareg transm
www.blauparts.com
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