Horrible MPG, Way too Rich

[Slut]

Alright.. bought 95 tsi not too long ago.. Car needs a serious amount of work... Now.. ive been doing a ton of searching... My car doesnt have many mods.. I just put on basically a knock-off injen intake... and new air filter... I made sure there no boost leaks in that.. I got a greddy boost guage, and car will boost to right before 1.0 so basically .9, and if i let off gas i get the loud woosh (on stock 2g bov). I AM NOT VENTING! heh.. Still very loud.. Can my 2g bov be shot... and I still really gatta check for boost leaks, but what would give me SUCH bad milage... I put in $25 yesterday.. finally got car to full... today im under half.. Yea i did some drivin.. but shouldnt be dumping this much fuel... If I WOT parked... I can sometimes smell gas... I'm sure its unburned fuel... Im installing Autometer Phantom A/F guage tommorrow, although I know they really dont tell too much.. I'm sure its just gonna tell me its rich.. I'm doing a complete tune up to try and figure why I'm using so much gas... Just got new NGK's.. waiting for wires to come in... I wanna change fuel filter as well, and I need to check my o2 sensor... I'm still retarded and havent reset my ECU after I installed intake, so i'm hoping maybe itll do something.. I also know my ISC is shot, but Im not sure what that would have to do with such bad MPG. I really would appreciate anyones input on this situation... Anything with my fuel system be shot? I'm even considering getting FPR to try something.. but maybe ill spend the money on SAFC... I'm wasting soo much cash on gas and I really gatta figure this out.. I'm going to replace 2g bov with 1g crushed... hopefully maybe itll help as well.. Other then that.. I love the car.. just needs a good amount of fixin up.. Thanks a lot.

 

[AdrenalineGSX]

hey, if you car is venting on the stock recirclulation that is where your rich is comming from you commputer is compensanting for the ammount of air that your MAS is telling plus it knows that its sposed to get some more and so if you have a leak there that could be why your running rich. i know that DSM's run rich anyways but unless your just spolling that turbo all the time you should be good on about 20 mpg which is what i get on the gsx but if you spool her her MPG's goes down to around 16

 

[dhonda]

Replace both O2 sensors.

 

[Sgt Turbo]

If you are smelling gas, you may have a leak, you need to rule that out or find it before you do anything else and also make sure you plugged in your MAS plug in when you were messing around with your intake pipe/filter.

 

[2gredspyder]

Do a full tune up, new spark plugs, check for boost leaks, and replace your front 02 sensor. my car was acting exactly the same way you are describing and it didnt even passed smog inspection, as soon as i replace the front 02 sensor it went back to normal and passed emissions with flying colors, gas mileage went up too and the smell of gas went away

 

[Slut]

Alright... Thanks bro.. Imma try that out... When I take old o2 off.. Should i be looking for any coloring... to see if its bad?

 

[Black95TSIawd]

yes my car is acting very weird like that. You can smell it being rich in the exhaust and if i'm revving her up in neutral you can smell fuel. Its been doing this quite a while. I have a small leak at my biss screw. I hope this is just my o2 sensor.

 

[Slut]

speakin of which... I aint got a cap for biss screw... I know my ISC is shot.. should see how it acts when i push a/c condensor on.. heh.. anyways.. Can I rtv a cap on over biss?

 

[Rick4g63]

Slut, I would replace both o2 sensors along with the fpr and PVC valve. If you have more than 60k miles and 5 years, definitely do it.

get the biss screw here
http://www.machv.com/newbasidsets.html

pvc valve
http://www.machv.com/1gdsmpcvvalve.html

Carefully remove the ISC, clean it, check for correct operation and re-install

 

[Slut]

Engine was replaced at 56k miles... I have reciepts showing o2 sensor was changed then as well.. i have 68k on my car now... Could it possibly foul out that quickly, it is basically two years old... anyways.. i dunno if the rear one was changed... could that have such an effect on my mpg?

 

[Black95TSIawd]

ah #### it, next weekend i'll do a complete tune-up. I changed my fpr from my parts car and it was working fine before i stopped driving it. I'll pick up a pvc valve, new from the parts store along with some new ngk plugs. I have an o2sensor on my parts car that was brand new used for maybe three months, but by now the car has been sitting for about a year due to a spun rod bearing. Do you guys think the o2 sensor is ok for use now?

 

[2gredspyder]

Do you guys think the o2 sensor is ok for use now?

it should be fine. rich conditions is what kills most 02 sensors.
it is not necesary to replace the 02 sensor on the cat. car will run fine even without it.
all it does it checks to see if the cat is working fine. the front one is the one that is necesary

 

[Slut]

So what color does the o2 turn when its goin bad... Will it be black... white?

 

[2gredspyder]

im not sure on what color it will turn, mines was like a burnt white

 

[blackGSX2g]

Also when you pull it out, try shaking it. Of the 3 o2 sensors I've seen go bad, when you shake it I heard a rattle. Thats a good sign that its gone.