im all stock and getting 15mpg city how is this possible?

[Fifty]

i have a turbo timer set at 2 minutes now its set at 1 minute because my car wastes gas like a v8.

im all stock and i only have a air filter. what could be the reason that i am getting 15 mpg city? i dont race i dont floor it all the time. should i go get the car tuned? maybe its running lean?
its a 97 gst with 84,000 miles. any clues or help for me?

 

[bones_420_99]

do you smell gas when you either shut the car off. also another thing that i would just check out is by putting some injector cleaner in a tank and run it through your system see how that works. kind of hard to tell what could be causing it with out knowing more. like when driving it are you at stop and go situations or are you driving like long distances without alot of stops in between.

 

[blackGSX2g]

Do a boost leak test and check your o2 sensor. I know I was getting around that fuel economy when my o2 sensor wouldn't work at anything over half throttle. I got a new one and got MAFT and tuned it up so I get around 23mpg city with me getting on it most of the time.

 

[Fifty]

i drive to and from school everyday which is about 1-2 miles away and on average it takes me about 4 mines to get there and around 10 minutes to get back because of traffic. i think i smelled gas 1 time when i was at a stop light and my window was down (95% i drive with window down dont use ac b/c it waste gas) but i wasnt sure it was coming from my car or a truck.

how do i check if my sensors are working correctly? (no check engine lights) and do i need to check both of them or just the intake?

you know how the 2g eclipse's fuel guage is divided into 4? i get around 50 miles per level so i get 200 miles on a full tank. last week when i was going to newport i took the 55 and i got around 70 miles and now i drove it to this day and it reads 110 miles and the needle is half way. should i replace the air filter back to the stock air box but i dont think it would help since i see a lot of modded out 2g and it still get a least 18 mpg

also about 2-3 weeks ago i left my lights on so i came out 7 hours later and the battery was dead and i had to jump start and it reset everything in my car like the radio and clock do you think it might reset any important computer things?

 

[bones_420_99]

As far as battery going dead and resetting something no that wouldn't be the case. I myself get about the same mileage that you are getting on your car running an aftermarket exhaust and intake so i think that there might be some confusion on how much gas mileage you are actually getting. If you are getting anywhere b/w 15-20 mpg I think that is around the normal range (or at least it is for me). I would suggest doing an injector cleaner (STP injector cleaner or something along that line) run the car for about a week and see how it ends up there. If you don't see any increase in mpg then you might need to start looking at like air filter and other things that could be causing issue here.

 

[AWDrift]

I have a similar situation, but I'm getting around 22 mpg city driving very responsibly(almost always slow). I think it is because of your driving habits...if the car never warms up to and from school, it uses more gas then if it were at normal operating temperature. Someone correct me if I'm wrong. You might as well replace the BOV along with the sensor, it isn't worth anything and is just leaking off excess air that your MAS is reading.

 

[Fifty]

so after doing some search i decide m gonna try some seafoam and injector cleaners since i see so many people saying that it works.
i dont know which one to do first thought should i do the seafoam 1st or injector cleaner? im also gonna buy some new fuel filter since i dont want to overwork my fuel pump due to all the jizz thats gonna be coming out of the gas tank due to the cleaners.

is there like a quality brand fuel filter i can buy or which one you guys recommend?

 

[Attack Eagle]

yep. Mitsu OEM


drop you TT down to 20 seconds low setting and 40 high...

unless you have been boosting you really don't need anytime but I like to leave the a/c on so both fans run... at least for a few moments...


make sure the air filter is clean, you have new plugs, and no leaks to casue a rich condition...

take the car down to Autozone and have a diagnostic check performed... I once had a friend with no check engine light because the light was out...


that being said drive it carefully but don't ly gagt around tryingto save gas not usingthe a/c... it doesn't make a huge difference in city driving, and your TT wastes a lot more than it does.

 

[AWDPetmitsu]

you know how the 2g eclipse's fuel guage is divided into 4? i get around 50 miles per level so i get 200 miles on a full tank. last week when i was going to newport i took the 55 and i got around 70 miles and now i drove it to this day and it reads 110 miles and the needle is half way. should i replace the air filter back to the stock air box but i dont think it would help since i see a lot of modded out 2g and it still get a least 18 mpg

I really don't see anything wrong with your mileage. I think you're chasing a problem that doesn't exist.

 

[HighPsi92GST]

I really don't see anything wrong with your mileage. I think you're chasing a problem that doesn't exist.

I get around the same as he stated...I didn't think it was bad either

And I don't quite understand how the stock air box will increase your gas mileage, although maybe I missed something there.

 

[AWDPetmitsu]

And I don't quite understand how the stock air box will increase your gas mileage, although maybe I missed something there.

Perhaps they're thinking that an open filter increases airflow which in turn calls for more fuel, but I think the increase is minimal, at most.

 

[Lsmith]

I am getting around that same amount of gas mileage on mine too. Only mods I have are a K&N air filter, MBC, and barely modded air can. I think its just to be expected on our cars. I might still check into the o2 sensor on your car being bad, thats always an option. Do you have a logger?? If so im sure you could search the site and find the normal rates at which that sensor should be reading and check that through your logger.

 

[blackGSX2g]

I don't think thats really normal. As I stated, I get around 23/24 in the city with me building boost in every gear almost all the time I accelerate (I know, I enjoy my car too much). My buddy gets about the same but babies it most of the time. I noticed my mileage increase from about what you are getting to what I am currently getting when I got a new o2 sensor and MAFT.

I got 23/24 city with the same driving habits on a stock 2g 7-bolt w/MAFT and a 1g BOV as well as with my built 6-bolt w/current mods.

If you are driving 'normally', that mileage indicates a problem. Your computer will not notice a problem with your o2 sensor unless it meets its stringent check conditions. I believe it is several consecutive cruises at 45mph or more for a straight half hour to an hour. Then and only then will it read an o2 sensor fault. Sometimes if the sensor is dying, it will flag a fuel trim code, but every car is different.

To test your sensor, hook a voltmeter to the o2 sensor pin on your ECU (Pin 78) and see if it cycles between .01 to 1v like it should. Over time they get slow and often don't cycle at all, which throws off your fuel trims.

For the ECU pinout, check out this link.

http://www.vfaq.com/mods/ecu-harness-2G.html

 

[evers310]

I've been having the exact same problem. I barely get 200 miles to a tank in my GSX. My RS gets around 330 miles to a tank. damn, I'm gonna miss that. Will a boost leak cause poor mileage? I think I may have a boost leak somewhere. Is the GSX gas tank the same size as the RS tank?

 

[c5chris]

I've been having the exact same problem. I barely get 200 miles to a tank in my GSX. My RS gets around 330 miles to a tank. damn, I'm gonna miss that. Will a boost leak cause poor mileage? I think I may have a boost leak somewhere. Is the GSX gas tank the same size as the RS tank?

Same as my GSX. At 200 miles, my gas gauge will be blinking orange.

My 02 sensor was to blame. It's ok in the morning when it just gets warmed up, but after that, my narrow band will never cycle. It will always be pegged at rich.

Check your 02 sensor and then do a boost leak test. There are alot of good advice here like checking your plugs ( I change plugs after 2-3 oil changes) and cleaning your open element filter.

 

[evers310]

Same as my GSX. At 200 miles, my gas gauge will be blinking orange.

My 02 sensor was to blame. It's ok in the morning when it just gets warmed up, but after that, my narrow band will never cycle. It will always be pegged at rich.

Check your 02 sensor and then do a boost leak test. There are alot of good advice here like checking your plugs ( I change plugs after 2-3 oil changes) and cleaning your open element filter.

Thanks, I'll check the O2 sensor tomorrow and make a boost leak tester.

 

[jayboogie]

seriously dude, i was in the same boat as you were two days ago. i made myself a boost leak tester for $5.08 grand total with CA taxes, hooked it up and pinpointed the leak (my #2 fuel injector). i fixed the leak today and took it out for a test journey... 40 miles later my needle hasn't moved from full... i was getting 25-28 mpg before my leak happened and im getting about the same im projecting.

good luck.