Fuel Problems?!

[MissMitsu]

So I just recently [back in May] picked up my first GSX. I was filling up my car about 3 times a week thinking nothing of it. Then I started asking people & they said thats not good. So today I took it to a show here where the owner of it has a 400hp GSX. I told him that im getting, if im lucky 120miles to a TANK. So he ran the codes on my & it threw a Fuel Trim code, which was being thrown a couple months ago & we didn't really think nothing of it. Well now its also throwing a TPS Sensor code. The guy told us some things what it could be. So we took out my dip stick & smelled it & of course we smelled some gas. Not strong but still smelled some. So I need HELP on what to really do next.

 

[TsiJohn333]

try replacing your front o2 sensor. i think that might be a good place to start and also do a boost leak test as well. i was getting around 110 miles to the tank before and pulled a fuel trim code and replaced my front o2 sensor and it fixed the problem. there are some types of o2 sensors you want to stay away from because our cars hate them but im using a bosch o2 sensor and my car seems to really like it.

 

[AllWheelRS]

Try doing a boost leak test if you can. I don't expect that if will totally solve your problem, but it'll defenitely cause you to run rich.

 

[96awd]

both guys hit it right on the head. Start with your smallest problems, least money costing problems and work from there.

 

[MissMitsu]

I asked the guy at the shop & he said not to worry about my 02 sensor. ### if it was that then it would throw the code for it. But do u guys think it would be worth taking it in for the couple hours for them the diagnosis what is wrong with it?! Its gunna cost me around 140 tho..ugh!

 

[99BoostedRS]

The reason your smelling gas at the oil dipstick tube is because your running so rich that the fuel is making its way through the piston rings. Its also probably mixing with your oil which is a very bad thing (It’s diluting the oil). So i’d get the problem fixed ASAP. You can check the O2 sensor with a multimeter if you have one or you can just reset the ecu and maybe you’d get lucky and it will fix it.

 

[AllWheelRS]

I asked the guy at the shop & he said not to worry about my 02 sensor. ### if it was that then it would throw the code for it. But do u guys think it would be worth taking it in for the couple hours for them the diagnosis what is wrong with it?! Its gunna cost me around 140 tho..ugh!

That is not absolutely true about the O2 sensor, there are alot of codes that can be thrown due to O2 sensor failure that are not O2 specific.

 

[MissMitsu]

Then will i need to change both the 02 sensors or just 1? What if changing the sensors dont work, where would i go from there? Sorry for so many questions im new to the whole boost aspect of these cars.

 

[Tyeler18]

The downstream (post cat) sensor does nothing for fuel economy, it's only there to make sure your cat is doing it's job. The upstream (off the o2 housing) is the one you'd want to replace if it's what's causing your poor fuel economy.

 

[MissMitsu]

Ok i was just checking. ### the guy at the shop started goin off saying how to change the back one & i started gettin confused.

 

[thach]

You don't have to go for the diagnosis since it's usually possible to find the answers to these sort of questions online. try googling it also.

Start off with a boost leak test. Test your oxygen sensor before replacing it if possible. I would look more into the causes of those codes if I were you, just to get more of an idea of where to look for problems.

 

[Absit]

Why don't you hook up a laptop with EvoScan and find out what your fuel trims and o2 sensors are ACTUALLY doing? Don't have the shop do it, you do it, and you review and post the logs.

Just as a reference I was getting 25 MPG in my '95 TSI AWD manual with mixed city/highway driving on93E0 fuel. It'd run around 300 miles before I'd want to fill up.

 

[68442]

If you get desperate you can borrow my front o2 to trouble shoot. My car is out of commission for the winter and plan on using a wideband for narrow band simulation anyways. I have evoscan also on one of my laptops.....never used it, got link instead.

 

[HaveBlue83]

i'm at 190 and about empty. i have a CEL for the rear 02 as i have no cat. i'm rich down low (10.5) and by 4,500 im lean (12.0+) WOT. im in the same boat, not fun.

 

[crazyboy81]

NGK O2 sensors all the way. Pre-cat. Also check your spark plug gaps.

 

[rlacasse1]

Well, if it is throwing a TPS code then why don't you start with testing/replacing the TPS?