2003 Jetta 1.8T mileage issues

[Twizzler09]

So lately the GF has been noticing that her Jetta isnt getting real great gas mileage. Matter of fact.... its getting roughly the same as my 4.0L does.

a little background on this car...

Its a volkswagon (obviously) Jetta, 2003 "Wolfsburg" edition, with barely over 65,000 miles on it. Its previous owner was a Hooters waitress, and she didn't drive it much. It actually sat for three years before my GF got it. Overall its in excellent shape, runs great and tooooons of power for such a small motor. But that comes with the turbo I s'pose. It has its little things that need doing, just from sitting for so long, had an exhaust issue which I fixed, and it needs a couple bushings replaced which is on the "honey-do" list.

Anyone know of some common issues with these cars that cause poor mileage? All the normal small things have been covered (air filter, fuel filter, etc) She has to drive to and from college every day and it acts like it uses almost 1/4 of her 14.5gal tank for a 35 mile round trip. Odd thing is, it doesnt smell like its running rich either.

The only thing I find odd is that I can hear the turbo spool very distinctly. It still has a stock style exhaust too. I've driven other 1.8T Jettas before and could never hear the turbo anywhere near this well. Comes on real early at around ~2,000rpm and seems to hit full boost by 3k, all on a motor that doesn't redline till like 6,500rpm. I mean it is LOUD, I can be inside my house and when she drives away at night I can hear the turbo spooling in the alleyway when shes moving at like 5-10mph....

Any ideas or suggestions? Possible that maybe the turbo has been played with? Or is that just a dumb idea....

 

[mentalbreakdown00]

Boost leak? Like in a connector, intercooler etc...

 

[Original_Ranger84]

Yeah sounds like there a leak somewhere after the turbo or something. Maybe the turbo got suped up and then caused a sensor or somthing to blow out cause the motor couldn't handle it?

I know my dads 2.0L gets around 26 - 33 mpg it a non turbo but runs at 3K pretty much all the time.

 

[Twizzler09]

I dont suppose that sensors for the turbo would trip a CEL would it? Such as a boost controller/wastegate sensor?

 

[mentalbreakdown00]

If it was large enough.. maybe.

 

[Apollo-Soyuz 1975]

I remember VW 1.8Ts having problems with ignition coil packs going bad if you so much as looked at them wrong... but if that were the case, the car would be misfiring and running like crap.

 

[Twizzler09]

Yeah it runs great, minus its insanely poor gas mileage.

Gonna spend some time this weekend looking it over, I had her reset her trip meter and fill up her tank today too so we can calculate its actual mileage.

Would a boost leak cause problems like this? I can see the potential for wierd-ness but never actually seen it before so

 

[Apollo-Soyuz 1975]

Boost leak would cause it to lose power noticeably.

You don't smell a gasoline leak around the car, do you?

 

[Twizzler09]

Definitely no power loss.... runs like a striped ape.

No leaks that I can smell or see, no puddles in the garage, no wet spots either. Great big nadda.

 

[martin]

Are the brakes dragging,

 

[Twizzler09]

Was just thinking about that.... shes gotta drive home from school in about an hour, so I'll check that out when I go over tonight for dinner with her parents, lol

 

[martin]

The other thought I had was "is she driving with one foot on the brakes" but I didn't want to ask.

 

[Original_Ranger84]

Well with the car on I would run my hand over all of the turbo tubes and see if anything is leaking out of the tubes or if you got canned smoke you could spray it around and see if there is anywhere it gets blown away.

Smell the brakes after she gets back and you should be able to smell the brakes getting hotor something.

 

[Twizzler09]

Well she got back from school a little early today, so I had to "borrow" her car from her while she was at work. Drove it around a bit and romped the heck out of it, then drove it back to her work and checked the temperature of the rotors. Three of the four rotors were virtually identical, the right front was a little warmer but only by a little, about 10-15 degrees difference. Dont think its enough to call it a stuck caliper.

Starting to think its got something to do with her driving habits..... I know she uses the cruise control alot, from what I've heard that never helps with mileage any. Either way shes only getting about 18-19mpg as it stands right now.

 

[Original_Ranger84]

Is that mostly city driving? Because the mileage ratings on those cars aren't the best, about 22-23 city and 27-29 highway. Romping around definately doesn't help and cruise control doesn't really help unless its completely flat.

If you drive off from stops normally instead of racing everyone i bet you'll see around 3 -4 mpg increase. (well thats what I have seen). Also does she carry alot of other things around in the car?