2005 BEW fuel economy

[S-TDis]

Hello fellow TDI friends,

Recently purchased my first TDI (2005 BEW 5 speed) for the purpose of commuting. I think I’m on track for a 900-950km tank (or 562-593miles).

so math works out to 38-40mpg is this ballpark? I was hoping to be in the 45-50 but maybe I’m dreaming I do have a check engine light on haven’t scanned it yet.

I drive it like a grandma, shift early to avoid higher rpm usually around 2000-2200RPM and stay in the highest gear possible while trying to avoid lugging (not sure what lugging does? Hard on trans?)

Any and all advice welcome thanks for looking and for all replies

 

[yahmon]

Ditch the egr

 

[irvingj]

Something's not right; I commute fairly often to my airfield, 27 miles one way. About 1/3 of that is on an interstate, the rest either 30-40 mph through three small towns, with 55 mph between towns. I consistently get 46-48 mpg and I drive at least what the limit allows (roads are heavily patrolled).

1) As I ALWAYS trip the vent on the tank and fill it all the way to the neck, I have better range -- do you know about the vent? I generally fill up at 600+ miles on "around town" trips (fuel gauge down to 1/4 +/-) and on road trips get around 800 miles on a tankful before the "get fuel" light comes on. Tripping that vent allows you to get about three more gallons into the tank.

2) Driving for mileage is OK as long as you don't overdo it, but you should also exercise that variable-vane turbo once in a while by really getting on it -- take it up to 4000 RPM every so often! This is NOT a long-stroke 3.5-liter DOHC Jag XK engine; it likes & needs some revs occasionally.

3) Get that CEL checked out! Find someone in your area that knows these cars well.

PS-- My Jetta is still totally stock, including the EGR valve -- but that valve DOES need to be cleaned every now & then. First thing I'd do is take a look at that, and check the engine air filter, too.

 

[oilhammer]

Look through my sticky thread in the Fuel Economy section. I can tell you right off you are driving it too easy if that is how you always drive.

 

[irvingj]

Listen to that guy!

 

[S-TDis]

Something's not right; I commute fairly often to my airfield, 27 miles one way. About 1/3 of that is on an interstate, the rest either 30-40 mph through three small towns, with 55 mph between towns. I consistently get 46-48 mpg and I drive at least what the limit allows (roads are heavily patrolled).

1) As I ALWAYS trip the vent on the tank and fill it all the way to the neck, I have better range -- do you know about the vent? I generally fill up at 600+ miles on "around town" trips (fuel gauge down to 1/4 +/-) and on road trips get around 800 miles on a tankful before the "get fuel" light comes on. Tripping that vent allows you to get about three more gallons into the tank.

2) Driving for mileage is OK as long as you don't overdo it, but you should also exercise that variable-vane turbo once in a while by really getting on it -- take it up to 4000 RPM every so often! This is NOT a long-stroke 3.5-liter DOHC Jag XK engine; it likes & needs some revs occasionally.

3) Get that CEL checked out! Find someone in your area that knows these cars well.

PS-- My Jetta is still totally stock, including the EGR valve -- but that valve DOES need to be cleaned every now & then. First thing I'd do is take a look at that, and check the engine air filter, too.
[/QUOTE

 

[S-TDis]

how low do you guys/gals run your tanks?

I know running diesels out of fuel is trickier then gas to get back going. My duramax has a primer for this but I’m doubting these cars do if I had to guess you got to bleed the fuel lines? Either way I don’t want to find out

here’s a picture of my current fuel gauge mileage does this look on par?


https://ibb.co/vJZ5M80

I’m unsure of the proper way to quote and add my reply

 

[irvingj]

I've come close a few times, but I'd rather not find out -- I still remember fighting with my '82 Peugeot 504D wagon, with its lever-type primer pump on top of the fuel filter. Bad memories.

These Jettas --I think-- are for the most part self-priming, but I just don't want to go there. I'll generally refill whenever my gauge reads less than 1/4 tank, anywhere from 500 to 600 miles, and of course soon after the "get fuel" light comes on, if I get that far.

As far as your fuel gauge -- #1, don't trust it... too much. #2, yeah, that seems close to what I'd expect of mine: 934 km translates to about 580 miles, which jives with my numbers above, albeit a bit less. I'll often hit the "get fuel" light around 600+ miles, maybe a bit more.

My fuel gauge is VERY nonlinear: when I fill it up to the neck (by tripping the vent button to get that extra 3 gallons in), my trip meter will register about 185 miles before the gauge even begins to move off "Full". After that, however, it moves down very quickly. At 1/2 tank, I'll be around 300-450 miles, but at 3/4 down (1/4 left) I'll often see "only" 470-550 miles recorded on the trip meter. I think the best I ever did at 1/4 remaining was 600, but I pushed it once and got over 800 when I started sweating bullets while looking for a diesel fuel station. (The "get fuel" light had been yelling at me for a while at that point.)

 

[S-TDis]

So if I’m understanding this right, you refill your tank when 1/8-1/4 and by the time you get there you’ve got around 500-600miles to your tank?

so I’m pretty close to the same mileage then? I’m at 584 miles with the above picture at roughly 1/8th tank.

how do you trip the vent ?

ALSO PROBABLY WORTH NOTING IT IS WINTER HERE, TEMPS ON AVERAGE FOR THIS TANK OF FUEL HAVE BEEN -2C to +5C or ( 28F to 41F )

 

[irvingj]

Yes and yes. (And yes, it's definitely winter here, too -- currently -10C in central NH!)

I'll fill my tank more often in the winter, just to keep it full (less room for condensation), but generally I'll re-fill anywhere from 1/2 to 1/4 tank and roughly 300-600 miles. At 1/8 tank, I'd expect to see more like 650-700 miles -- of course, depending on how many "around town" miles vs. interstate miles I've driven.

Tripping the vent -- there are threads about this, but there's a captive space in the tank (that's built in), kind of a bubble at the top, to allow for expansion of fuel when it's hot out. If you look into the filler hole, you'll see a small --1/4" diameter or so-- "button" thing protruding from the left side of the inside of the filler neck, maybe 2 inches in. When, with normal filling, the filler nozzle clicks off, you can get more fuel in by pushing that button inward/downward, allowing trapped air in the upper portion of the tank to escape. It's easy enough to use the fuel nozzle to push that button in/down; fiddle with it and you'll hear air escaping when you get it right. As that air escapes, you can get more fuel in, in my case pretty much always about 3 US gallons-- about 120-140 miles of extra range!

There are threads about permanently disabling that vent button --see "VENTECTOMY" in this forum-- but I've never done that, I just deal with it by using the fuel nozzle to push on it. Takes a bit more time to fill up that way, but it's easy enough to do. (And besides, I'm lazy.)

And if you do that, consistently, and use a calculator to figure your miles per gallon (or liters per 100KM), you'll get an accurate measure of fuel usage. Those numbers you can trust.

And I repeat what I said above!! Get that CEL read, and push that little beast every so often; it needs it to function properly!

 

[Lug_Nut]

I dont know about the upper end of your expectation of 50 mpg. My 2005 BEW 5 sp. wagon returned an average of about 45 (5.1~5.2 l/100km). My driving pattern / technique appears similar, so I'd expect similar results.
I do suspect your calculation methods. Don't use miles or km per tank. Use the distance travelled over the volume needed to re-fill to the pre-trip level. If you don't fill to the same volume each time (it's cheap at this station, so you squeeze in all you can. You only have $20, so you stop pumping then) you'll need to average several of these to obtain an average for the cumulative distance.
The use of maximum acceleration pedal position COMBINED WITH low rpm can become an issue due to high combustion force (torque) and more time (lower rpm) to squeeze the oil film out of the rod bearings. Be aware of this. Limit the frequency and duration of WOT at under 1500 rpm, and drive on.

Don't fear becoming a "Lug-Nut".

 

[S-TDis]

I dont know about the upper end of your expectation of 50 mpg. My 2005 BEW 5 sp. wagon returned an average of about 45 (5.1~5.2 l/100km). My driving pattern / technique appears similar, so I'd expect similar results.
I do suspect your calculation methods. Don't use miles or km per tank. Use the distance travelled over the volume needed to re-fill to the pre-trip level. If you don't fill to the same volume each time (it's cheap at this station, so you squeeze in all you can. You only have $20, so you stop pumping then) you'll need to average several of these to obtain an average for the cumulative distance.
The use of maximum acceleration pedal position COMBINED WITH low rpm can become an issue due to high combustion force (torque) and more time (lower rpm) to squeeze the oil film out of the rod bearings. Be aware of this. Limit the frequency and duration of WOT at under 1500 rpm, and drive on.

Don't fear becoming a "Lug-Nut".

I only calculated my first tank in it. I did this by resetting the trip gauge/meter on the cluster I ended up getting 597miles (955km) to the red bar and the fuel light hadn’t come on yet. I’m assuming I could have squeezed another 30miles out of it.

This is how I did my math

955 / 1.6 to get km to miles = 597

597miles / 14.5 (supposed tank capacity) = 41.17mpg

not sure how much fuel was really in it, as far as I know it doesn’t have the ventectomy and I didn’t push the pin so really I could have got more mileage out of it. When you say 45mpg I’m assuming that’s with the extra 2 Gallons the ventectomy lends ? I should be right in the ballpark then

 

[hskrdu]

The way to accurately measure fuel economy is to divide distance by actual fuel consumed, based on filling up to the "same" level as your previous fill. Obviously, filling to the same point each time is often not consistent unless you remove the vent and fill the fuel all the way to the top, which is why most owners don't read too much into a single tank. With multiple fills, the difference in fill level and amount will even out over time, and you'll have a good sense of your FE. If you use the same process to fill each time (or the same stations), your fill level will be remarkably close each time. FE will also vary greatly with driving style, city-hwy, ambient temps, winterized fuel, tire psi, load, etc. A good running BEW with 5 speed should be able to get 50 MPG on the highway, but you likely won't see it in the winter, or in the city.

Note your car is listed as a 2002, not 2005....

 

[teitel39]

I have an 04" BEW A4. I drive it pretty spirited most the time. it has 238k on it, no egr, colt cam, Malone
tune aVNT17 turbo upgrade. gets 40 all over town/highway. I couldn't be happier with the performance. I've never had a car get 500 plus miles to a tank of fuel sooooooo.

 

[Tdijarhead]

I’ve had my 05 for 8 years during that time I’ve broken 800 miles a handful of times with the best being 817 if I recall. Of course I vent when I fill, actually I’ve done the vent removal operation. I typically see 200 miles before the needle even thinks about moving off the full mark, 500 miles at the halfway mark, and almost always over 700 miles per tank.

During the winter that will be slightly less 650-725 miles per tank, summertime 725-800 miles per tank. 50-55 mpg summertime, 44-48 miles per gallon wintertime. I never get caught in heavy traffic unless I get caught behind a tractor hauling a manure spreader on a two lane highway. 393k miles, no tune, I have replaced the cam at about 284k with an idparts kit.

I have recorded almost every fill up since I’ve had the car.

 

[TDikook]

my 2006 Golf is as highly modified as you can do with OE parts. I get about 42 mpg. look at my sig for the fuelly tag.

 

[TDI_FNG]

When I replaced the thermostat on my 04 Jetta, I noticed almost a 3 mpg increase. It was operating at around 175. Those extra 15 degrees made quite a difference.

If I get less than 42 mpg, I'm bummed, unless I've been idling quite a bit. This is with a stage 1.5 from Malone and spirited driving. With a vented tank, I can make it from Seattle to Twin Falls, ID on a tank of fuel.