Hey Guys,

Firstly I have used the search button and found a few threads suggesting my cat is dead. However, I also noticed there is a lot of conflicting advice/suggestions as to what to do.

I get this smell occasionally (after normal driving) usually when I stop at the traffic lights with the Air con on. My fuel consumption is horrendous (14L/100K) according to the computer (I havent reset the ECU since purchasing this car). My car is a TH '99 exec, since owning it (7 weeks) I have replaced: Air Filter (KN), Fuel Filter, Spark Plugs (rear and front bank - iridiums), Spark Leads (Topgun - i know, they are shit after i researched), Oil flush and change to Penrite, Oil filter, Coolant flush and change and Bendix CT pads.

On top of this, It idles really rough (around 700-750RPM) when at the lights in "D" gear (foot on brake). It idled rough (intermittent) when I first purchased it but put it down to the things that I have replaced however it is still present.

I'm not too mechanically minded but would you put this down to maybe a dirty throttle body?

Apart from these drama's the car is in great condition and is really pleasant to drive.

Thanks in advance for all your help.

Usually the rotton smell comes from LPG converted cars, So it may not be you... Might just be the Aircon sucking in from outside the car?

Im no pro, But it may be another explanation as to why it's happening.

I had a bit of a rotten egg smell from my TL every now and then from the exhaust, had the cat removed and replaced, turned out the original cat was fine... so i dunno where the smell came from...

well on thr idle issue, it is a well known fault on these cars, depends what you mean by rough. is it actually missing or does it feel a little bumpy in drive with brake on? listen to your exhaust and see if it actually misfires. alot of people, me included have a slightly rough idle, even after replacing damn near everything. mine doesnt miss at all and is in perfect running order but in drive i can feel a vibration, no movement on the rev gauge. i think a split engine mount can cause the same problem, so check them for splitting etc. as for the cat, i suppose you have no choice but too replace it, im glad i live in NZ, no emissions testing=no cat converter=extra power ha ha . clean green NZ!!

Thanks Guys for the replies.

In response to your questions robssei - it doesn't really miss it's just the vibrations and the needle on the RPM odometer goes up and down slightly from anywhere between 700RPM - 800RPM - it doesnt feel like its going to stall but the longer I sit at the lights the more it does it.

Anymore insight into the rotten egg smell? I have also thought about LPG cars but it's also done it to me when alone at the lights (no other vehicles around).

how is your temp guage, is your water tempt normal? there is a possibility the sensors or thermostat could be faulty which send false readings to the ecu.

you can delete double post :)

temp is fine, sits a bit below half, doesn't go any higher.

before blaming the cat, lets look at other options.

1) Try and different petrol station and different RON fuel
2) The engine could be running rich and not burning off all the fuel during the cycle, is reaching the cat and the sulphur in the fuel is being converted to hydrogen sulfide.
3) Check the condition of the following: spark plugs, spark leads, think about doing an oil and filter change. Possibly oxygen sensor as well, this can often be the culprit for bad economy.

Once you have exhausted the above options (which should be done anyway as part of preventative maintenance) then get the cat checked out

I thought that eggy smell is from the cat converter?? I remember smelling it when I bought my car (and it was a brand new car). I could be wrong...

before blaming the cat, lets look at other options.

1) Try and different petrol station and different RON fuel
2) The engine could be running rich and not burning off all the fuel during the cycle, is reaching the cat and the sulphur in the fuel is being converted to hydrogen sulfide.
3) Check the condition of the following: spark plugs, spark leads, think about doing an oil and filter change. Possibly oxygen sensor as well, this can often be the culprit for bad economy.

Once you have exhausted the above options (which should be done anyway as part of preventative maintenance) then get the cat checked out

Thanks for your advice but clearly you did not read my first post correctly.

I have changed petrol and petrol stations (many times, however always use premum unleaded). Number 2 means nothing to me. Number 3 was addressed in my first post.

How can I diagnose the oxygen sensor? Or is this best left to a mechanic?

Sounds like your oxy sensor with that poor economy, hense you cat is storing all the unburnt gunk.

cheers, will get it looked at. Anyone know a part number and/or supplier of where i can aquire a replacement o2 sensor?

well i had that smell when i converted from using RON 91 to RON 98 it was there for 2-3 tank loads i think its mixing of the fuels that does it,

to check the o2 sensor you need to unplug it and see if your economy rises
if it stays the same your o2 sensor is fine

It comes from certain petrol types/brand. try a different brand. BP never gave me issues. I dont think my Cordia had a cat, but i still got a smell from it sometimes.

It comes from certain petrol types/brand. try a different brand. BP never gave me issues. I dont think my Cordia had a cat, but i still got a smell from it sometimes.

The smell is from the sulfur in the fuel being broken down chemically inside the cat