MUCH lower mileage Jetta wagon v. sedan!

[grg144]

Hi, I've owned a 2003 GL Jetta sedan since new, and never got less than 44 mpg under any driving conditions. It now has 73K+ miles on it.

Just bought a 2004 GLS wagon with 53k+ on it, and am getting much worse economy (37-38 mpg) in exactly the same mix of driving. It also idles a little rough, which the sedan does not. Don't know if that's related.

Both are manual xmission.

Any ideas as to cause and cure?

Thanks in advance,

Gary Grossman
VA Piedmont

2003 GL Jetta Sedan
2004 GLS Jetta Wagon

 

[fase2000TDI]

Have you hooked it up to a vagcom yet?

 

[grg144]

Have you hooked it up to a vagcom yet?

I'm arranging to do that in the next day or so. I'll be back with the results.

Thanks,

 

[mrGutWrench]

Hi, I've owned a 2003 GL Jetta sedan since new, (snip) Just bought a 2004 GLS wagon

__. Are both autos or 5-speeds?

 

[grg144]

__. Are both autos or 5-speeds?

Both are manual 5-speed.

 

[domboy]

2003 GL Jetta Sedan
2004 GLS Jetta Wagon

Well, based on my understanding of model year changes, it would appear that you've got two different motors:

2003 Jetta - VE engine
2004 Jetta - PD engine

That could account for some of the difference...

 

[PDJetta]

I get about 46 - 47 MPGs in my '04 5-speed PD. And that is in mixed driving. You should be at least getting 42+

--Nate

 

[mrGutWrench]

Both are manual 5-speed.

__. I put about 130K on an '02 sedan. I averaged 57 MPG over that mileage and I expected to get 61-62 MPG per tank for the last 50K of that (in the summer, it went down a couple in the winter). I bought an '03 wagon* about the first of December. It had terrible, cheap tires (just got them off this week) and most tanks have been 50-52 MPG. Also, I haven't done the mixture modification yet - dunno what that's worth.

(*both 5-speeds).

 

[grg144]

All of the posts to date (and for them I am most appreciative) seem to support my notion that I should not be experiencing this reduction in mileage going to the newer wagon. We're going to put it on the VAGCOM tomorrow (Thursday) morning to see what we can see. More after that.

Thanks,

 

[grg144]

We put it on the VAGCOM this morning and ran both the MAF sensor measurement and the turbo measurement. The graphs were nearly identical to those in the Ross-Tech instructions.

We were unable to get the VAGCOM to access "group 000" in order to run the timing measurement. Is that because it is a PD?

I guess it's safe to conclude that the MAF sensor is OK.

Am I right that if the actual turbo boost tracks the requested boost, that there is no intake problem? Any answer to that or any additional comments, suggestions, or questions would be most welcome.

Thanks,

 

[tango_28]

PD sucks when come to MPG.

 

[mrGutWrench]

PD sucks when come to MPG.

__. Be careful, T-28, you're going to get a reputation for being down on PD's ... like my reputation. Dunno how I got it

 

[Kalin72]

I have 2005 Wagon, PD engine, 15K miles, Tiptronic, 20% highway 80% city driving returns 30-33 miles per gallon. I don't think this is too low or unusual. The wagon is heavier than the sedan. Also check the air pressure in the tyres.

 

[mrclean]

I have a 05 Jetta wagon 5spd with 63k on the clock. Running RC2 for 52k miles. Factory clutch still in. I get 44-46 all around driving. Couldn't complain if I wanted to.

 

[mctdi]

We put it on the VAGCOM this morning and ran both the MAF sensor measurement and the turbo measurement. The graphs were nearly identical to those in the Ross-Tech instructions.

We were unable to get the VAGCOM to access "group 000" in order to run the timing measurement. Is that because it is a PD?

I guess it's safe to conclude that the MAF sensor is OK.

Am I right that if the actual turbo boost tracks the requested boost, that there is no intake problem? Any answer to that or any additional comments, suggestions, or questions would be most welcome.

Thanks,

The PD is likely to get less MPG. PD rated 100 HP / 177 FT-lb, per PD was 90 HP / 155 FT-lb. In the USA the PD started with model year 2004.

Also VagCom does not do as much on PDs. Timing check being one.

Ben

 

[IndigoBlueWagon]

Several thoughts: did you run actual versus requested mass air flow? If the actual is lagging your MAF may be slowly going out. Do you have fresh filters in the car (air/fuel)? You're due at 60K but it could be that these are affecting your mileage. How clean is the intake? Another possible culprit if the car was driven gently.

Also, I noticed a marked improvement in fuel economy and how my wagon ran after it passed 60K. I think 38 is on the low side. I'm getting about 40 in my A5 5-speed, in mixed driving and I don't even have 10K on it yet.

 

[RichS]

My PD does OK!

Just to give you some data points.

2005 TDI Wagon GLS 5sp:
Average MPG: 42
Worst MPG: 38
Best MPG: 48

I currently have about 52,000 miles on it now. So, yes you should be doing better.

 

[grg144]

Several thoughts: did you run actual versus requested mass air flow? If the actual is lagging your MAF may be slowly going out. Do you have fresh filters in the car (air/fuel)? You're due at 60K but it could be that these are affecting your mileage. How clean is the intake? Another possible culprit if the car was driven gently.

Yes, ran actual vs. requested MAF. During accel from 2500-3500 RPM actual exceeds requested until RPM reaches about 3400, after which it lags very slightly.

Fuel filter is new. Don't know about air filter or the intake. I'll look at these next, as well as pumping up the tires.

Thanks,

 

[silverbox]

Are these oe tires?
The OE tires tend to be low rolling resistace tires.

 

[IndigoBlueWagon]

Just for reference, I drove to Waterfest and back yesterday in my wagon. 614 miles. 47 MPG. That was with the cruise set at 75 whenever I could, and some stop and go and light-to-light running in NJ. I was a bit disappointed--I was hoping for 50 MPG. But Jeff warned me that the ASV tune will cut into mileage.

At any rate, in the same conditions as I was in yesterday (A/C running most of the day, too) you should get similar mileage.

 

[grg144]

Are these oe tires?
The OE tires tend to be low rolling resistace tires.

Not even close - the OE tires were Michelin's (at least that's the spare), but the previous owneer replaced them with "National Ovation", which I think is actually made by Bridgestone.

I've got Yokohama AS430's on my sedan and I'm going to swap them this week before I sell the sedan.

 

[Fletch63]

2005 Jetta Wagon PD .... MPG

I have an 05 Jetta TDI Wagon w/5spd, .... 18,000 miles on her. I too have been dissappointed in my mpg, .... my driving is 80% hwy/20% city. I avg a very consistant 42mpg. My highway speed is 70mph on cruise. I'm not really complaining, ... I had simply hoped and have experienced better.

I use to have an 03 TDI Golf w/5spd and got an avg of 49mpg with the same type of driving and style.

Any thoughts to improve my PD's mpg ???

Thanks !

 

[Steve-o]

I have an 05 Jetta TDI Wagon w/5spd, .... 18,000 miles on her. I too have been dissappointed in my mpg, .... my driving is 80% hwy/20% city. I avg a very consistant 42mpg. [snipperoo]

I use to have an 03 TDI Golf w/5spd and got an avg of 49mpg with the same type of driving and style.

You're taking a hit on mileage partially because your Wagon has the PD engine and the Golf did not. And you don't say what kind of mileage you had on the Golf, but you're still breaking in the Wagon. That's a bunch of MPG right there. You might also check tires/tire pressure and really calibrate your mileage calculations (IOW, ventectomy if they have vents in the '05s, etc.)

 

[danielttt]

Tires screwed me on my wagon

I have a '05 wagon. Historically my absolute worst milage was 38 mpg's in the first 55,000 miles. I put new Goodyear tires on to replace the MX4 Michelins 10,000 miles ago (current odometer 65,000)....With these tires, I can't get out of the mid to high 30's on the mpg's unless I get out and push...
Also, seems the milage drops from the mid 40's to the low 40's and high 30's with the summer heat in florida. This is my 3rd summer with this car and I'm assuming the a/c drag and intercooler inefficiency are taking their toll. Hope to see the 40's again in the fall.

 

[shake_rattleandroll]

I have a 2001 Jetta w/manual trans.and have gone from 48-50 mpg for the first 6 years of driving, to 38-41 mpg in the past 3 months. I have changed all filters, oil change, adjusted timing belt twice and the tensioner, and just cleaned intake manifold...yet none of these has made one bit of difference. It does not matter which fuel I use, it's the same. It doesn't matter how I drive, where I drive, or the weather or the tire pressure...it's still the same crappy low mpg. I can't for the life of me understand what has happened. It is NOT in my head! This is REAL. Just hope it never happens to you!

 

[GreeningTX]

'04 Jetta wagon, manual, 58K miles, OE tires, B20, no mods, avg 51 mpg mixed driving in suburban environment over past 9 months. My driving regime during this period: shift @ 2200 rpm except shift from 4th to 5th at 45 mph; cruise at 45 mph as much as possible when not on highway, 60 mph on highway; religiously coast in gear whenever possible; foot off accelerator when a yellow or red light is in view or anticipated; few if any jackrabbit starts; engine off at long lights; avoid AC except in summer afternoons and when spouse is in car; tire pressure a bit above what VW recommends; no Jack-in-the-Crack ball on the antenna; smile as folks race past.

Wife's '05 Jetta sedan, automatic, 35K, OE, no BD, no mods, avg. about 40 mpg in same environment over same period with a much more conventional driving regime. And she wonders why.

 

[grg144]

'04 Jetta wagon, manual, 58K miles, OE tires, B20, no mods, avg 51 mpg mixed driving in suburban environment over past 9 months. My driving regime during this period: shift @ 2200 rpm except shift from 4th to 5th at 45 mph; cruise at 45 mph as much as possible when not on highway, 60 mph on highway; religiously coast in gear whenever possible; foot off accelerator when a yellow or red light is in view or anticipated; few if any jackrabbit starts; engine off at long lights; avoid AC except in summer afternoons and when spouse is in car; tire pressure a bit above what VW recommends; no Jack-in-the-Crack ball on the antenna; smile as folks race past.

Wife's '05 Jetta sedan, automatic, 35K, OE, no BD, no mods, avg. about 40 mpg in same environment over same period with a much more conventional driving regime. And she wonders why.

This is a good time to provide an update on my '04 wagon's economy. I had the car serviced at the local dealer because I didn't know whether any of the recalls had been done. I swapped the National Ovation tires that came on the wagon for the Yokohama AS430's on my '03 sedan, inflated to 35 front and 41 rear.

We're now on a long trip, avoiding population centers and spending long periods at 62 to 77 mph, depending on prevailing conditions, laws, and customs. We use the A/C in the afternoons, as the temperatures are averaging well above 90 F. And I'm coaching my beloved co-driver on the appropriate use of the transmission. Result: even at these speeds, we're getting 40-41 mpg instead of the 36-38 we were getting before.

Not great, but better.

 

[thermopylaetech]

Just a point here byt the wagons are rated at a lower CD but slightly higher curb weight. The waggy has the lower CD, about a point over the sedan, becasue of the long roof and rounded tail.

I've been keeping casual track of my milage and with country road driving with the air on going to lime rock I was getting a nominal 43mpg.

 

[WDM]

I'm getting 42 mpg average now in almost exclusively spirited city driving. Take it out once a week and run it at 80 - 110 mph (140 - 185 km/h) for a while, bone stock, mileage is ever so slowly increasing. There's only 30K km on my car and this is riding on Nokian WRs (40F/36R). I can only imagine that a whole tank or two at leisurely highway speed would easily net me close to 50 mpg, never done it though...

 

[GreeningTX]

Just a point here byt the wagons are rated at a lower CD but slightly higher curb weight. The waggy has the lower CD, about a point over the sedan, becasue of the long roof and rounded tail.

What is "CD"? And is it lower than the sedan's, or higher (you seem to say both)?