So I bought a Wrx with a 185,xxx for 2 grand any ways the car ran fine but needed a clutch. Fixed drove it around it was fine. Then I installed a catless down pipe and a blitz nurespec race after that while driving the car it started to smoke while coming to a stop. I can get on the throttle and nothing. But somtimes it smoke while stopping. Change the pcv valve still dose it. Also I there is a lil bit of oil in the top mount. Also the car has new plugs coolant and oil. I was guessing either the turbo is going or my valve seals are going bad. Car dose not over heat and runs fine and no codes. any help would be appreciated. Thanks

 

I am not sure how the wrx is but on the stil if you run a down pipe cat less or not you need some kind if ecu tune. Most popular and easiest is Cobb. Maybe it has something to do with your air/fuel levels idk just a thought?

 

As for the oil maybe look into an oil catch can?? But if the smoke is white/blue you could be burning oil.

 

does your turbo have any shaft play?

 

Little oil in the top mount is normal. It's from your breather lines on your heads being recirculated back into your intake.

If you feel like spending some cash, a wideband airfuel ratio gauge is a wise investment. It'll really help with diagnosing problems.

Then you can be sure whether or not you're running rich.

 

what color is the smoke? blueish white, white, dark grey, black? did you tune after downpipe install?

 

Cat less down pipe won't cause the smoking. I would know.....way back when, when I had a brand new 03 wrx I ran catless a dp and up and a CAi without a tune for over 2 years no tune. Never blew never smoked.

 

Just because you did it doesn't mean it was advised. The car requires a tune after doing this. Any time you play with the A/f especially if you remove a cat. Some cars have a sensor on the DP too

 

1. depending how recent the exhaust work....perhaps burning off any residual oil on the exhaust

2. removing the stock exhaust you maybe removed heat shields which arent a part of the aftermarket system so any oil that gets on it is burning.... look for small oil leaks...

3, does the smoke linger? if it does....its burnt oil....and itll look bluish....
blackish smoke is raw fuel...and whiteish is coolant which usually dissipates really quickly...


how does removing a cat change a/f ratios?

 

It isn't fuel. He does not need a tune with a catless dp install.

Please explain how the A/F ratio of a 2.0 wrx with a td04 running a factory 16bit ecu with OEM map is changed enough to cause smoke out exhaust by installing a catless DP.

A catless dp simply increases exhaust flow. In this situation the factory boost control solenoid is not utilized beyond capacity.

There is a AFM reading intake air volume and an oxygen sensor monitoring a/f ratio. Using these and other variables, the ecu sets injector pulse and ignition timing based upon predefined tables.

So when slightly more air is brought into the engine due to increased exhaust flow it is monitored and compensated for.

Yes, this car does have a sensor on the DP. It is there simply to see if the catalyst is oxidizing the carbon monoxide into carbon dioxide. That is it's sole purpose. It does nothing but assist in keeping tree huggers happy (which makes no sense because carbon monoxide is reactive and picks up oxygen atoms to become carbon dioxide...and trees love that ish)


Astin, you should double check your air filter too because it could have changed your A/F ratio enough to blow smoke out the exhaust. HAHAHA

 

Thanks guys I kno for sure it's oil I can smell it I have no oil leaks on the motor the smoke is coming out of my exhaust I had a friend follow me to confirm it's coming out of my exhaust it dosnt constantly smoke it's only somtimes. I think it's gonna come down to my turbo or valve seals hopfully not my rings

 

My bet is turbo is getting a little tired, new td04's are super cheap so change that puppy out!

 

Had a similar problem turned out to be valve guides

 

Astin,

Do you also have an aftermarket BOV installed?

 

No I don't stock still