fuel consumption and hesitation at throttle

[knighteclipse1]

Very new to this, but i have not seen any answer to my problem on this sight hoping someone can help, ever since i got a 3 inch turbo back installed (without cat) my car has been getting 13-15 mpg (was 27 mpg) and studdering (hesitaiton) at throttle. I pulled the plugs and they were covered in black sut. and my exhaust seems to be belting out this as well...i had it professionally installed at polk performance in Little Rock. my cel went off i assume because of my O2 sensor. No one seems to know whats wrong with it. I had it dynoed before the exhaust install... it had 184.5 hp/ 196 lb/ft , and it was very fast...i assumed this mod would help it but it didn't. doesn't seem to be any shaft play in the turbo. PLEASE HELP!!!

 

[I-luv-em-all]

You most likely have a boost leak, click here to find out how to make one www.vfaq.com

If you don't have any, then it is probably your O2 sensor (the first one that is). Try those things first.

 

[ddavisaf]

Please don't post the name of the shop that you had work done at. There's another section for that.

Alright. Without another real upgrades, and exhaust (especially a 3 incher) won't help you much. But it's needed for real power gains with more upgrades. The black soot you're talking about on your plugs and out of your exhaust is carbon. Carbon is usually caused by crappy gas. And it'll make your car run horribly.

What CEL is poping? Most likely it's EGR or O2. I would start with the CEL, whatever is it, replace the component and then we'll start from there. Post back and let us know what happens.

 

[knighteclipse1]

Sorry about naming the shop. I'll remember that. Thanks so much for answering these questions for me. I will check them all and get back with you. I know the CEL code had something to do with the fuel trim...but thats all i know...thats what the guy said at the shop. when i first got it back from the exhaust install, it idled horribly and ran bad. it is better, but like i said, its studdering for lack of a better word during acceleration. mind you, its still pretty quick. but not like it was, something i am not happy with thats for sure. i also have noticed the boost is running around 15-18 psi. (more towards the lower end of that) Also having problems with my clutch pedal not going all the way to the floor after its been driven awhile, it feels as though it has resistance in the last 20% of travel. but it goes away after its been sitting awhile. and it gets worse the longer distance that it is driven. i have replaced the slave cylinder and master cylinder and clutch and preasure plate and have a fidanza flywheel installed as well (geez...should i have started another thread for this one guys?) any suggestions?

 

[VBGSX]

If you're not sure what the code is or don't have a friend with a logger that can tell you, go the the local autoparts store(autozone, Advanced Auto, etc). They can and usually will check the code for you. They'll not only tell you what it is but they'll do it for free.
Post back your results here.

Next thing is to do the boost leak test:
http://www.vfaq.com/mods/ICtester.html
This is definitely something you(everybody) should do. Boost/vacuum leaks can cause all sorts of problems and if you have any, you will never see your cars full potential.

Good luck

 

[knighteclipse1]

o.k. just came back from the local autoparts store and they checked the code its p0170 something about fuel trim on bank 1. when i check it in my haynes repair manual it doesn't show that code. it does show p0171 as system adaptive fuel too lean(bank 1) I am really confused now

 

[knighteclipse1]

I want to thank all of you who helped out...no boost leak...it was the o2 sensor which was causing the problems. Smoked a Acura today

 

[dsm john]

i have a p0170 code too , what did you do to the sensors to fix it ?> was it the sensor after the cat ?

 

[knighteclipse1]

i replaced the O2 sensor before the cat (assuming i had one ) when they installed my three inch turbo back exhaust the shop eliminated the one behine where the cat went. replacing the sensor was pretty straightforward. and it made a very big difference.