MPG's??

[supraguy17]

So I've had my car for about two weeks now. The first week I drove it pretty hard expected to get crappy mpg's. The car has CEL for o2 sensor and it needs a tune. I went to the gas station yesterday and filled the car. Only got 115 miles out of the tank. Car clicked full at 9.5 gallons yesterday and was a little past the full line on the gas gauge. Well so far I haven't driven hard, shifted below 3k rpm every time I've driven the car, only gone 42 miles and I've already gone from full to 3/4. Do these cars naturally just get terrible gas mileage? With the tune up and new o2 sensor I'm hoping for some better mpg's.

 

[bNasty]

thats actually pretty good. i remember going usually only 25 miles on a full take but i still got about 250 out of a tank. A tune would help and the fact that your cel is for your o2 means that its not working. If you replace it youll probably get better mpgs and it will run better.

 

[GsXdSmKingGsX]

When I had my bad 02 sensor I got like 3Mpg but as soon as I replaced it, it went back up to 28. Is your car throwing the open loop failure code too?

 

[SuperFudge]

I looked it up and evidently these cars have a 16.9 gallon tank and i still have the original window sticker for my talon and according to that they get an estimated 22 city and 31 hwy. I just filled mine up the other day and driving it around i have gone about 110 miles and im still over 3/4 of a tank.
So i would change the O2 sensor and also do a basic tune up/maintenance like plugs, wires, TB cleaning, and other stuff.
Hope this helps

 

[jakelandry]

So I've had my car for about two weeks now. The first week I drove it pretty hard expected to get crappy mpg's. The car has CEL for o2 sensor and it needs a tune. I went to the gas station yesterday and filled the car. Only got 115 miles out of the tank. Car clicked full at 9.5 gallons yesterday and was a little past the full line on the gas gauge. Well so far I haven't driven hard, shifted below 3k rpm every time I've driven the car, only gone 42 miles and I've already gone from full to 3/4. Do these cars naturally just get terrible gas mileage? With the tune up and new o2 sensor I'm hoping for some better mpg's.

I by no means consider myself a gas milage guru, but i monitor my mpg every second. The o2 sensor and tune is definitely a problem, but it shouldnt be that bad.


When you put in the 9.5 gallons were you filling up from dead empty? If so then either A your float is bad or B the previous owner liked to store bricks in their gas tank.


A few more common questions you can ask are: Do you have ANY BOOST LEAKS? Do you have any leaks within any of the lines? Is your fuel pressure normal? Is your tps set at the correct voltage? Do you have ANY BOOST LEAKS? Do you have a logger? If so monitor your throttle percentage as your drive ( provided that you have your tps set to the right voltage ). Do not get the throttle percentage over 20% on acceleration and 15 on the interstate. Do your tires have the right psi in them? Have you thought about http://www.dsmtuners.com/forums/newbie-forum/222686-seafoam-works-merged.html And oh yes....do you have any boost leaks?

You could always check these 1558 posts and see if your any different than the others. http://www.dsmtuners.com/forums/newbie-forum/1415-bad-gas-mileage-merged-9-6-a.html

 

[nyTalonTsi]

When I first bought my TSi I was getting horrible mpg. After doing a complete tune up, and changing the fuel filter mpg got way much better. There was so much gunk in the filter. The plastic bov was leaking too.

But yeah expect loss in mpg if your throwing any CEL and especially for an o2 sensor.

 

[supraguy17]

Thank you everyone for the replies. I just got back from the garage, appointment at 2:30 for oil change, and there going to do their basic 52 point inspection. I'll find out what the codes are when I get back. After I leave there I'm going to pick up new o2 sensor, serpentine belt, and whatever else I may need.

 

[Tyeler18]

My friend's o2 sensor is out on his 2g gsx too, he gets about 130/ tank. My gf's GST spyder on the other hand gets around 26 in town.

 

[xxxspeedxxx]

i must be luck. when i bought my eclipse i was getting 25-26 miles per gallon.

 

[ziggo0]

I noticed my gas gauge does down fast from full to half, then slower from half to empty. Weird these cars...still in the 20's for mpg w/ e85.

 

[jukematt]

It is the O2 sensor mostly like people have said. I was getting around 15 mpg until I changed it. Now I get over 20 in the city unless I'm boosting all the time. On the trips home from school during breaks (4 1/2 hr drive) I get about 29-30 on the HWY. Hopefully it is the front O2 like mine that was super easy without getting under the car.

My CEL is trying to throw a code for the rear O2 but it isn't bad enough yet.

 

[90gen1tsi]

I keep track of my mpg too and before I stated having TPS problems I was averaging 27

 

[supraguy17]

Thanks again everyone. I'm hoping it is just the o2 sensor like everyone has stated and the front one at that. The previous owner had a full turbo back exhaust on the car and I haven't been able to crawl underneath the car and see if it even has a rear o2 hooked up or even a spot for it.

So just got back from the garage, overall pretty happy with the results considering it could be a lot worse. They said I don't need any of these just suggesting I get them done sooner then later. CV boot and ball joint on passengers side are starting to get loose and there is a very tiny hole in the exhaust after the cat. Parts and labor for these thing to be ordered and installed came out to $502.50 or right around there, don't have the paper in front of me.

Engine Codes:

x2 P0170 - Fuel Trim Malfunction Bank 1

P0105 - MAP/ BARO Circuit Malfunction

Anybody have any ideas on these codes?