Help please!!! Lowering MPG

[robin0107]

2012 Passat TDI

I got my Passat on March 2012 and I am very happy with it. Giving from 790-815 per tank until mid november 2012, by this time I put 30,000 miles on it. after mid November til today is doing about 700-750 per tank, took it to the dealer and they said the car is fine, nothing wrong with it, now has 33,000 miles. I convine city and highway on this records. I am very conservative driver, not aggressive and no more than 70-75 on highway. This is my first TDI and I am very concern, my cars last a lifetime cause I keep maintenance and everything on time. Help please.

 

[FormerGasser]

Winter fuel and colder weather is to blame.

 

[r11]

+1. Definitely worse MPGs in colder weather/winter formulation. We will be back to 50+ hwy MPG when spring comes.

 

[Papachristou]

another +1 to winter fuel and lower temps (longer warm up). every car does it, you just notice it more on this car because you get such good MPG you actually pay attention to the MPG

 

[Softrockrenegade]

+1 on winter fuel and colder temps being the cause . I went from 45-47mpg fills to 43-44 mpg fills now that winter has hit (and my car isn't broken in yet). Btw it's not wise to go below a 1/4 tank before filling .

 

[TDI_Dan]

I don't go past 1/2 tank. That way there is less chance of moisture entering the tank. Also you don't spend as long at the pump when it's very cold out. A frost heater is also a great investment in my opinion. Instant heat, and a happy, more efficient engine. Easier starting. Win win win.

 

[Moltenburn]

I don't go past 1/2 tank. That way there is less chance of moisture entering the tank. Also you don't spend as long at the pump when it's very cold out. A frost heater is also a great investment in my opinion. Instant heat, and a happy, more efficient engine. Easier starting. Win win win.

This ftw ^^^^^

 

[tdiatlast]

Robin0107: Where are you in TX? How cold is it? I wonder how much "winter" fuel is pumped in S. TX?

 

[robin0107]

Since mid November temp are from 28-50s. One day or the other 60s.

 

[robin0107]

Thank everyone for your response, I can sleep in peace now.

 

[robin0107]

How do my fuelly.com record appear in my posts here?

 

[carlrx7]

more info on this frost heater please!

 

[Lightflyer1]

Fuelly supplies a link to post in your sig.

A search on frost heater will tell you everything you want to know and more.

http://www.frostheater.com/

 

[tdiatlast]

carlrx7: Private message sent

 

[Aja1]

I suspected it was temps and fuel, but nice to hear that it isn't something else. I've noticed poorer MPG since the temps have been colder. But no complaints here.

 

[Papachristou]

you guys dont go past half a tank!!!??? why did you buy a tdi again?

 

[Lightflyer1]

Don't go below 1/2 a tank, right. I feel bad if I don't fill up with at least 16 gallons every time. Use the tank, that is what it is for. Just don't run it empty. When the light comes on, fill it at your leisure and before it gets to empty. No good reason in the world to fill at half a tank IMO. A Frost Heater is probably way overkill for Texas as well. Just resign yourself to the loss of economy for the few cold days we have here. From the OP's numbers above it is only a 3 to 5 mpg loss. You could make that up by slowing to 65 to 70.

 

[phlfly]

I never filled full tank since there is no reason to caring so much mass with you, I do just over half a tank. I fill a full tank just for long trips

 

[Lightflyer1]

This causes inaccurate fuel readings as you never know if you filled it to the same level every time. Partial fills are a pain, whether it is the first half or the second half. When I fill mine it is always right up to the lip of the filler tube, to the point of almost overflowing.

 

[TheGrove]

I fill up every other day, takes a little over 12 gallons each time unless I did some extra errand running at lunch.

 

[DubFamily]

I haven't lost any economy yet from "winter" fuel; I think perhaps my winter additive concoction is working

 

[RonJitsu]

Have you changed your fuel filter? My MPG's were going down as I approached 20K miles. Changed the filter @ 20K and the MPG's are right back up where they should be.

 

[Papachristou]

why fill up at all? im hiring an 18 wheeler and am going to have it direct pump into my tank

 

[hmt]

+1. Definitely worse MPGs in colder weather/winter formulation. We will be back to 50+ hwy MPG when spring comes.

Not trying to switch subject, but when you guys say you get 50+ hwy MPG, do you REALLY getting 50+ MPG by refilling and calculating your MPG or is that 50+ number based on the Average MPG on your MFD while you're driving.

I am getting 45 MPG 100% hwy that's why I am really curious if something is wrong with mine. Mine is '13 TDI 6M has a little more than 2K on it...Maybe it's still under break-in period...I am getting about ~35 MPG 100% city...

 

[FormerGasser]

Not trying to switch subject, but when you guys say you get 50+ hwy MPG, do you REALLY getting 50+ MPG by refilling and calculating your MPG or is that 50+ number based on the Average MPG on your MFD while you're driving.

I am getting 45 MPG 100% hwy that's why I am really curious if something is wrong with mine. Mine is '13 TDI 6M has a little more than 2K on it...Maybe it's still under break-in period...I am getting about ~35 MPG 100% city...

I drive 95% highway. Best tank was 49.2mpg (hand calculated). That's with ~2k miles on the clock. Expecting better once the weather gets warmer here and winter fuel goes bye bye.

 

[Lightflyer1]

Driving style is everything. Your car is fine.

 

[hmt]

Driving style is everything. Your car is fine.

I do agree with this comment if it's city driving. Since it's 100% hwy and my house is 2 minutes from highway, no traffic during the 520 miles trip, no stop...speed between 65 - 80 (depending on speed limit)....Used all gears...no aggressive...very steady...

So that's just like driving automatic, therefore driving style doesn't really apply on this case unless I am missing something else....

 

[Lightflyer1]

If you are varying between 65 and 80 mph, that will have something to do with it. Anything over 65 mph or so will really kill the economy, but 45 mpg isn't bad for what you are doing and better than rated. Driving style is "the" biggest factor in whether you get good economy or not, city or highway. Maybe read some here and try to use what you can without agravating those around you:
http://ecomodder.com/forum/EM-hypermiling-driving-tips-ecodriving.php

 

[Yankinwaoz]

Not trying to switch subject, but when you guys say you get 50+ hwy MPG, do you REALLY getting 50+ MPG by refilling and calculating your MPG or is that 50+ number based on the Average MPG on your MFD while you're driving.

I am getting 45 MPG 100% hwy that's why I am really curious if something is wrong with mine. Mine is '13 TDI 6M has a little more than 2K on it...Maybe it's still under break-in period...I am getting about ~35 MPG 100% city...

Yes. That is how I did it. The key is driving style.
I did an experiment. I had to drive from Tucson to San Diego. That is 400 straight miles of mostly empty highway, and most of it is flat and straight. I filled up in Tucson, topped up in Yuma, and filled up again in San Diego. I had set the cruise at 60mph and I got 52 mpg.

Sometimes there is a nasty headwind across the AZ desert which can make a big difference. That day it was quiet. So I think my mileage is pretty accurate.

 

[APT]

Winter fuel, 2k miles, cooler temps, all impact fuel economy. Diesels seem to be more affected than gasoline powered vehicles. And 10% hit at 45mpg looks bigger (quantity) than at 15mpg.

Expect to jump up at least 10% this summer. Diesels also tend to brake in over more miles, like 50k+ instead of 5-10k of today's gas engines.

Check out www.fuelly.com for fuel logs many owners like to use. Here's one Passat TDI owner averaging 52mpg over 16k miles. 50mpg is real, possible for you. Closer to 70mph in the spring/summer are your best times, warm temps but no AC.