Bad Gas Mileage [Merged 9-6]

[99GST]

I am still getting some pretty bad gas mileage.

I am only getting about 19.7 mpg with mostly city driving shifting at 4k.
I have already replaced my front O2 sensor and am looking to replace the fuel filter.

I have a 99gst with about 55k miles on it. Should my fuel filter already be bad?

What else should I check or change? I have NKG plugs and Accel wires are on the way.

Thanks,
Nathan

 

[knochgoon24]

Not really. The turbo will just spin faster to make up for the difference. And the T25 spools so fast that you don't always notice a decrease in spool.

 

[EatMuhBoost99]

Yea I was just dealing with a terrible boost leak from my bov c clamp popping off because it won't seat right. The turbo still spools but you feel hardly any pull.

 

[kilmore]

Bad fuel pump? Bad fuel regulator?

 

[hypergenesis]

Yea I was thinking one of these could have gone bad I might start with the fuel filter since thats one part IDK when has been changed or if it ever has

 

[overboosted1g]

Well start by doing a blt you can make a tester for under $10 from parts at a local home depot, as for your o2 sensor you can let it soak with some penetrant such as pb blaster etc. Also you can put either a pipe wrench or a pair of vise grips on it and use a little heat if all else fails.

Sent from my HERO200 using Tapatalk

 

[brandonwh64]

This started happening to me two weeks ago. i put 25$ in gas and it gave me a half a tank well i drove about 30 miles and was touch empty! come to find out i had broke off the temperature sensor while jacking my engine up to change something. i replaced it and it drives alot better now

 

[hypergenesis]

Where is the temp sensor located it would make sense because it started getting worse after I jacked up my car trying to take off the o2 sensor in the front.

I know you can make BLT for really cheap but then you still need an air compressor, ive honestly been too busy to get anything recently 8 hour shifts at work + 12 hour days at school are no bueno.

Also @overboosted1g Im assuming a torch would be the best way to hopefully take it off if im not mistaken?

 

[brandonwh64]

Where is the temp sensor located it would make sense because it started getting worse after I jacked up my car trying to take off the o2 sensor in the front.

I know you can make BLT for really cheap but then you still need an air compressor, ive honestly been too busy to get anything recently 8 hour shifts at work + 12 hour days at school are no bueno.

Also @overboosted1g Im assuming a torch would be the best way to hopefully take it off if im not mistaken?

I really dont know were it is on a 4G63 since i have a 420A but i would think it would be close to the thermostat

 

[hypergenesis]

Hmm mind posting a pic of what it looks like I keep trying to search up for the part under temperature sensor but for some reason other things show up or nothing at all.


As for the tune up thing I just put in 8.5MM magnecore spark plug wires with NGK BP6s gapped at .028

 

[GRAVEDIGGER]

Here you go.
http://www.dsmtuners.com/forums/newbie-forum/190667-93-talon-coolant-temp-sensor.html#post1588123

Good luck!

 

[hypergenesis]

so most of the sensors are just right around the radiator cap? Also how would you test one of the plugs to see if its good or not? just test with a voltometer with the car off to see if its 0 then recheck it when the cars on and the temp sensor is running?

 

[brandonwh64]

Remember there are several and there is one in the radiator too for the fan.

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Steve

Source

 

[AK Thunder]

if you have an OBD2 scan tool or have access to one, take a jumper wire to the 5volt reference wire and the ground wire, if the data on the scan tool goes wayyy outa whack then the sensor is good, if nothing happens then the sensor is bad

 

[hypergenesis]

Sadly I don't have access to one really other than the local mechanics. I honestly need to figure this out this gas mileage is ridiculous , also how would you test injectors and how often do you change your fuel pump

 

[GRAVEDIGGER]

so most of the sensors are just right around the radiator cap? Also how would you test one of the plugs to see if its good or not? just test with a voltometer with the car off to see if its 0 then recheck it when the cars on and the temp sensor is running?

You need to check the resistance of the sensor to determine if it is bad or not. Just unplug the coolant temp sensor connector and check resistance across the sensor. Depending on the temperature the sensor will have a different resistance. Here's what you should be seeing when comparing temperature to resistance values.

temp resistance
32* 5.9 ohms
68* 3.5 ohms
104* 2.7 ohms
176* 0.3 ohms

 

[Archer Fabrications]

320 miles to the tank? damnit i only get 275-290 on my gst. that sux

i know this is old... but i get 18MPG... with boost leaks.... 200Miles per tank thats real bad..... this is also before a 6 bolt swap... im guessing leaky throttle body, and boost leaks

 

[sean44kyle55]

I drive a 95 tsi awd, was wondering what mileage you guys usually get from a full tank because right now i'm getting about 170 miles from a full tank which seems ridiculous. Also wondering if any of you have had something like this before i have replaced front o2 sensor and plugs and wiresand nothing has helped so far

 

[FIBA M - EC17PSE]

I get about 300-330 depending on if im on the motorway or not. I did gain more mpg when i added my new air intake kit. But 170 is low! Did you replace the rear o2 aswell?

 

[TurboTsiThatFly]

Most likely its your right foot that kills your gas mileage. I personally get about 360-380 miles out of a full tank of gas. What rpm do you normally shift at? And have you done a boost leak test. etc...

 

[Anubis_4_99]

I drive a 95 tsi awd, was wondering what mileage you guys usually get from a full tank because right now i'm getting about 170 miles from a full tank which seems ridiculous. Also wondering if any of you have had something like this before i have replaced front o2 sensor and plugs and wiresand nothing has helped so far

I see your in omaha, i'll gladly trade you my 96 RS which gets about 350-400 out of a tank

Most of what is probably killing your mileage is your driving habits.

 

[alex209]

Sounds like a heavy foot ,when's last time you did a tune up

 

[RedGST98]

its not always the way you drive.. I have a n/t 98 talon auto trans that i get about the same in miles.. im happy to hit 200 on a full tank.. my turbo i get about 300+ but the other im in the same boat as he is.. and i dont have a lead foot in the n/t..

 

[Anubis_4_99]

its not always the way you drive.. I have a n/t 98 talon auto trans that i get about the same in miles.. im happy to hit 200 on a full tank.. my turbo i get about 300+ but the other im in the same boat as he is.. and i dont have a lead foot in the n/t..

We said it's probably mostly his driving habits, because that is one of the largest factors for gas mileage there is. The rest is the health of the vehicle and how well its maintained. You shouldn't be getting under 200 miles on a full tank, especially on a N/T, i get over 300 driving like a huge D-bag. My last long trip which was just a week ago i averaged 32MPG.

In my old turbo talon i get an easy 350 when i was easy on it. When i was boost happy it would fall down into the mid to high 200's.

He has other threads talking about boost leaks, idle issues and other things as well, so its safe to assume he has other issues that could be contributing to his MPG, he needs to fix the issues he knows about first before trying to trouble shoot bad gas mileage.

 

[crash89]

How many gallons does it take you to fill up. It also could be that your fuel gauge is off and you are thinking you are almost empty but really youre still half a tank. That was the case in my spyder for the longest time. I get about 240ish in my 1g driving pretty normal with the occasional boost. Usually hit 12 gallons to fill up.

 

[RedGST98]

We said it's probably mostly his driving habits, because that is one of the largest factors for gas mileage there is. The rest is the health of the vehicle and how well its maintained. You shouldn't be getting under 200 miles on a full tank, especially on a N/T, i get over 300 driving like a huge D-bag. My last long trip which was just a week ago i averaged 32MPG.

In my old turbo talon i get an easy 350 when i was easy on it. When i was boost happy it would fall down into the mid to high 200's.

He has other threads talking about boost leaks, idle issues and other things as well, so its safe to assume he has other issues that could be contributing to his MPG, he needs to fix the issues he knows about first before trying to trouble shoot bad gas mileage.

i know bro.. i wasnt trying to start anything.. was saying in my own experience its not always the driver.. and yeah in a n/t 200 is bs... dont drive it much unless im out of gas in the turbo and need parts or what not..