[savenger]

Just bought a 2009 i30CW petrol 2.0 and having intermittent issue with exhaust smell in the cabin while driving. I've tried turning off the HVAC system entirely, closing the vents, putting it on recirc only. Problem persists.. just been driving around with the windows down and copping it. bought a carbon monoxide detector on ebay so I'll be keen to measure it once that arrives.

Bought it dealer used so I took it back. Mechanic walked me through the exhaust system and insisted it's holding pressure, though I'm not sure how thorough he was. He checked/cleaned out the cabin air filter and checked the seal on the rear hatch.

fuel economy has been very mediocre too. averaging 12.5l/100 city driving. maybe not related but noteworthy.

Anyone else had this problem? My theory is that there's a small leak in the exhaust system and the engine bay is filling with exhaust fumes which makes its way into the cabin but I'd love some guidance.

[CraigB]

City driving in the 2ltr will cause high fuel usage, if you think you might have an exhaust leak the first tell tail signs would likely be heard and some black soot developing around the area.

If around the engine and cabin is where you suspect then first check the flex pipe at the base of the headers, they can start to split and not be noticeable with the stainless mesh that covers them.

Get a exhaust shop to inspect and if an issue is found take report back to your dealer for replacement.

[Dazzler]

Welcome savenger,

Wow, that fuel economy does seem high even for city driving.. I'm guessing it must be a 4 speed auto? The Wife had a 2.0 petrol 6 speed manual CW and that was giving around 8 L/100 kms average but we only live in a small city. Can't remember last time we had a traffic jam...

My first thought was an exhaust leak. Craig has offered some good advice as usual... 

[sundiz]

High fuel consumtion and smelly exhaust sounds like O2 sensor issue. But that would most likely illuminate MIL light.

[savenger]

^^ thanks everyone.

carbon monoxide meter showed some intermittent readings inside the cabin, seems to be originating from the around where the shifter is. seems very random, sometimes it's fine, other times there is a strong smell and the detector goes off.

got it up on a hoist and had a look for exhaust leaks - appears to be fine. mechanics theory is that the catalytic converter may have some level of carbon buildup or blockage and exhaust may be feeding back into the engine bay. Very expensive to replace the cat and may not even be the issue so I'd rather avoid that.

would an ODB2 meter be helpful in diagnosing an 02 sensor or cat issue if the MIL light isn't coming on?

[Dazzler]

^^ thanks everyone.

carbon monoxide meter showed some intermittent readings inside the cabin, seems to be originating from the around where the shifter is. seems very random, sometimes it's fine, other times there is a strong smell and the detector goes off.

got it up on a hoist and had a look for exhaust leaks - appears to be fine. mechanics theory is that the catalytic converter may have some level of carbon buildup or blockage and exhaust may be feeding back into the engine bay. Very expensive to replace the cat and may not even be the issue so I'd rather avoid that.

would an ODB2 meter be helpful in diagnosing an 02 sensor or cat issue if the MIL light isn't coming on?

You could try the RSPCA You could maybe get one off a low mileage wreck cheap?

Thanks for the update too.. we always appreciate those.. please continue to keep us in the loop. Helps others going forward that might experience a similar issue. 

[sundiz]

would an ODB2 meter be helpful in diagnosing an 02 sensor or cat issue if the MIL light isn't coming on?

Many of the cheap scan tools are able to read the 02 sensor values from the diagnostics port. If the values are OK, then the issue is somewhere else. If the sensor was fubar it would light up the MIL light.