Ok, so I guessed that the fumes are normal as there are no cats to deal with them but I'm amazed how rich my car it at tickover. In traffic the cabin fills with exhaust fumes after a minute or so, is this normal?

I assume the rich (like my old metro with the choke out) tickover is a result of there being no cats? When I drop my lad off at school I near choke everyone when I stop at the kerb

Car is a Hatch STi with a full H&S decat and Mishimoto CAI.

TIA

Ian

 

Is this all the time, or only when cold?; newage run rich until warm, maybe hatches are the same

 

Depends on the mapping my jdm was mapped really rich at idle tht bad if i stalled it cold i could not get it started again lol could be a faulty lambda id get it checked by the mapper

 

Have you got a wideband gauge fitted so you can check AFR's?

 

i had this after decatting but it's because I re-used the donut gasket. Once the new donut went in I wasn't getting knocked out by the fumes in the cabin anymore.

did you get proper subaru gaskets fitted at the time or just re-use the old ones or (even worse!) use the ebay type gaskets?

 

Did you upgrade the fuel pump ?

Siv

 

Mine smells rich and when it's cold on idle... No smell when warm

 

Ok, lots of suggestions

Yes it had an updated pump fitted.

I assume new gaskets were used as it was a complete, new turbo back fitted.

Mine smells all the time, its no better after 120mile run than first thing on the recent cold mornings.

I don't have a wideband. Its, hopefully, booked in with the mapper at the end of the month. It was only mapped at the start of august so it might be the lambda has gone since then.

Ive never had a decatted car so I didn't know whether this was normal.

 

Sounds like the fuel pump gasket could be unseated, it's quite easy to snag it and put a kink in it when refitting.

This happened to me on my last re map and the fuel was trickling down the back of the tank, smelt really strong inside the car.

Siv

 

Re fumes, what type of crank case breather / catch can setup are you running?

 

Standard as far as I'm aware, would an upgrade/aftermarket one help?

 

I've had 2 fully decatted and mapped imprezas and have never had trouble with fumes or running rich.
Only time with fumes was when uppipe to manifold gasket went..

 

Did you find out what was happening?
I have similar, WRX-S Hatch with ej20 bugeye fitted, AVCS, Fuel rails, FPR, Decat, Syvecs and all mapped
Mine is popping constantly at speed off throttle as well, so definitely over fuelling. It's back in now to be looked at. Any info greatly appreciated ;-)

 

daF1rby - is your syvecs fitted with the wideband sensor? If so you may just need your closed loop fuelling setup.


Fatboy, has the car been mapped for the mishimoto intake? Only times I've had fumes into the cabin is when the donut gasket has gone in the downpipe - other than that all smells go out the back and even then it wasn't overly powerful.

 

Yes it was mapped with all of the mods on. The problem went away but has reappeared in the past few weeks. I think it's the lambda sensor, as I'm now sitting in traffic a lot and it's not getting revved very often.

Interestingly Matt C had the breather arrangement changed on his hatch to solve the same problem. Apparently it's overly complex

 

Thanks for your reply, mines been back in for over a week and has now been diagnosed as cyl 3 down on pressure, so this is where the unburnt fuel was getting thru :-(
Currently in the process of getting another ej20 STi engine fitted
And I bought this one so I didn't have the chocolate piston problems! Ha ha! :-/