Decat'ing my car

[grimstoner]

I have a Peugeot 206 2.0 Gti. After being in a little accident (appropriated by the local carwash) and being repaired, it's had this little issue.

On cold mornings, after driving about 2km's (dunno if it's time/distance/heat dependent), I'd get a dashboard warning stating "Catalytic Converter Fault" and "Pollution failure", after which it'd start misfiring terribly. Once I've switched it off, and start again, the warning is still displayed, but the car runs fine. After about a week (if it doesn't happen again), the warning goes away.

After reading a bit, I saw that it is possible to "decat" my car. What does this involve? What happens to the fuel-air mixture? Is it then still controlled by the onboard computer? Is fuel consumption worse/better? I assume also that it'll sound a bit more Brakpan then? If I decide to resell it, will there be issues with the new taxes?

Anyone know of a place that'll do it in the east of Snorcity?

 

[spiderz]

Take the cat by the back of the neck and slowly remove it from the car without it scratching you. (or the car)
Your car is now de-catted

 

[4Motion]

You will get much better performance with a downpipe and decat.
Do it!

 

[Pitbull]

I have a Peugeot 206 2.0 Gti. After being in a little accident (appropriated by the local carwash) and being repaired, it's had this little issue.

On cold mornings, after driving about 2km's (dunno if it's time/distance/heat dependent), I'd get a dashboard warning stating "Catalytic Converter Fault" and "Pollution failure", after which it'd start misfiring terribly. Once I've switched it off, and start again, the warning is still displayed, but the car runs fine. After about a week (if it doesn't happen again), the warning goes away.

After reading a bit, I saw that it is possible to "decat" my car. What does this involve? What happens to the fuel-air mixture? Is it then still controlled by the onboard computer? Is fuel consumption worse/better? I assume also that it'll sound a bit more Brakpan then? If I decide to resell it, will there be issues with the new taxes?

Anyone know of a place that'll do it in the east of Snorcity?

That happens if the air fuel mixture is not right. Just get it dyno tuned and it should be fixed. The engine is giving the warnings because the mixture is wrong.

 

[Gnome]

I only know of 2 methods in general. There may be specific methods for you vehicle tho that I'm not aware of.

A bit of techinical detail: The catalyzer has a oxygen sensor before and after the catalyzer, it detects a problem by analyzing the air before and after.

Anyway, Method 1:
Chip or change the engine map

Method 2:
A small catalyzer box thingy that is fairly small is installed, this box contains the oxygen sensor and just a small amount of exhaust passes over it to fool the sensor, it is therefore much less restrictive. It'll still wear out over time but it doesn't cost an arm and a leg (well it does but much less so than the full size variant). Good thing is no modification of the electronics needed.

Method 1 might be bad if something goes pear shaped with the "chipping" or changing of the map or the device they install to fool the ECU.
Method 2 is very safe but it will usually be more expensive but it is the safest as far as I know.

 

[Naks]

Method 2:
A small catalyzer box thingy that is fairly small is installed, this box contains the oxygen sensor and just a small amount of exhaust passes over it to fool the sensor, it is therefore much less restrictive. It'll still wear out over time but it doesn't cost an arm and a leg (well it does but much less so than the full size variant). Good thing is no modification of the electronics needed.

AKA mini-cat. Specialist shop like Powerflow should be able to do this for you, may cost a couple of grands. A new cat will set you back anything between 5-10K.

Get it done

 

[Gnome]

AKA mini-cat

Ah yes, thanks, forgot the name

Example for the OP: http://bigdaddiesgarage.com/mini-cat-cel-fix.html

 

[Pitbull]

I can't believe you people?

He wants his car fixed you and give him conversion ideas
So much for asking good advice in this section I guess...

 

[riscbroker]

But no-one's answering the OP. I'd also like to know, can you remove the cat and have the vehicle dyno tuned without attracting legal or mechanical issues? I've heard horror stories of turbo issues following cat removal....

 

[Laserdick]

Go to Powerflow, there are often 2 cats - have both done as the other will soon go too.

That happens if the air fuel mixture is not right. Just get it dyno tuned and it should be fixed. The engine is giving the warnings because the mixture is wrong.

I am willing to bet that you are quite incorrect. The misfire is caused by the cat that has most likely disintegrated inside the pipe blocking the exhaust path from the engine. He can replace the cats/s but it will cost a packet and they'll go again eventually. The best thing he can do is have Powerflow remove the cats and place the O2 sensor in such a way that it fools the computer.

I can't believe you people?

He wants his car fixed you and give him conversion ideas
So much for asking good advice in this section I guess...

Chill - the advice is sound, see above. No one suggested he have any conversion done that falls outside the gambit of fixing the issue he is having.

@OP: so it soon - your car is most likely underperforming drastically as well as using too much fuel and the misfire could easily lead to ignorant/tricky mechanics suggesting bent valves and head removal. Powerflow shouldn't charge much over R2k for this job.

 

[Gnome]

I can't believe you people?

He wants his car fixed you and give him conversion ideas
So much for asking good advice in this section I guess...

I think you misunderstand the concepts and therefore don't think we are giving him a solution. I've listed 2 thus far.

I'd also like to know, can you remove the cat and have the vehicle dyno tuned without attracting legal or mechanical issues? I've heard horror stories of turbo issues following cat removal....

We did answer him and YES it can cause mechanical issues. Depends which method you take. With the min-cat modification the chances of having mechanical issues are 0 if the shop did it correctly. Legal, I'm not sure, probably not legal but police don't have the technical expertise to diagnose it anyway and even a mechanic would need to look VERY carefully to spot you removed the catalyzer and fitted a mini-cat. And that is if he even knows about mini-cat's.

 

[Naks]

But no-one's answering the OP. I'd also like to know, can you remove the cat and have the vehicle dyno tuned without attracting legal or mechanical issues? I've heard horror stories of turbo issues following cat removal....

We suggested the most cost-effective solution to his problem.

Without the mini-cat, you would need an engine remap to tell the ECU to ignore/fake the input from the O2 sensor. AFAIK, a dyno tune can't do that. A remap is significantly more expensive and dyno tunes are somewhat unreliable.

 

[Gnome]

Without the mini-cat, you would need an engine remap, to tell the ECU to ignore the input from the O2 sensor. AFAIK, a dyno tune can't do that. A remap is significantly more expensive and a dyno tunes are somewhat unreliable.

Spot on.

 

[SirFooK'nG]

Sent my astra 180 to Powerflo for the minicat. Had to get a branch for the car as my cat is part of the exhaust manifold. A new cat is ridiculously expensive, the whole conversion took a couple of hours, and set me back about 4K. The car sounds so much better, performance is wayyy better (my old cat was pretty blocked - 180K km). An my low range torque kicks in earlier! Worth every cent!

 

[grimstoner]

I am willing to bet that you are quite incorrect. The misfire is caused by the cat that has most likely disintegrated inside the pipe blocking the exhaust path from the engine. He can replace the cats/s but it will cost a packet and they'll go again eventually. The best thing he can do is have Powerflow remove the cats and place the O2 sensor in such a way that it fools the computer.

I'm willing to bet that it's not causing a blockage. This happens about twice a month for the past year, most frequently on cold days. After the said restart, the car runs fine and I don't suspect it's underperforming at all; there are also no weird sounds. Also, over the last couple of months, I've recorded about a 9l/100km consumption, which I believe is pretty good for a 2.0 NA engine, so not using too much fuel.

Which leads me to believe that it might just be the sensor itself?

there are often 2 cats

Isn't there 1 cat, but 2 oxygen sensors?

Is there a Powerflow in Pta?

 

[Adeptus Mechanicus]

@Pitbull: I'm glad you don't work on my car, mate. You have no clue.

@OP: The decat/min-cat option will be the cheapest and most effective solution to your problem. It is likely that the lambda sensor and/or cat matrix itself is stuffed. Replacing this with an OEM solution will likely be costly.

 

[riscbroker]

OK thanks guys, I've got the drift now

 

[Gnome]

Did you by any chance ever fill up with LRP/leaded feul instead of unleaded or use additives that contain particles that stick to the exhaust (eg. lead additives). In that case it's the o2/Lamda/Oxygen sensor that is screwed.

Will be cheaper to repair if it is only the o2 sensor. They are fairly expensive tho.

 

[blaaislaai]

Get rid of the CAT.. you will get uptoo 10% extra performance. a mini-cat is about R800 at powerflow.. it basically just fools the ECU that the CAT is present while its not.

 

[Pitbull]

Go to Powerflow, there are often 2 cats - have both done as the other will soon go too.



I am willing to bet that you are quite incorrect. The misfire is caused by the cat that has most likely disintegrated inside the pipe blocking the exhaust path from the engine. He can replace the cats/s but it will cost a packet and they'll go again eventually. The best thing he can do is have Powerflow remove the cats and place the O2 sensor in such a way that it fools the computer.



Chill - the advice is sound, see above. No one suggested he have any conversion done that falls outside the gambit of fixing the issue he is having.

@OP: so it soon - your car is most likely underperforming drastically as well as using too much fuel and the misfire could easily lead to ignorant/tricky mechanics suggesting bent valves and head removal. Powerflow shouldn't charge much over R2k for this job.

Sound advice? What if his car is still under warantee or something?

As for me being incorrect, that is very likely. I mentioned it because I had the exact same problem. It turned out that there was a problem with the air/fuel ratio. This cost me an arm and a leg to have it fixed at a dealership. After I paid the invoice the clerk said I could have had it changed via a normal Dyno tune.