Unusual Decat Emissions Issue!

[unfortunately_french]

Hello All,
Had an RS192 on my car for approximately 3 weeks now, has been ok so far however today when driving the car (a mixture of fast and eco driving) when doing some eco driving suddenly the emissions warning light came on. When it did I wasn't surprised considering the car has a DECAT fitted, however I was surprised that it's only just come on now when the DECAT has been on for 3 weeks?

Now I know that nearly everyone with a DECAT has there emissions light go on after fitting, however has anyone had it like me where it was fine for a substantial amount of time and then randomly came on? I'm running tesco 99octane so it isn't a fuel issue. Can't see it being lambda either really unless the sensor suddenly packed up while I was driving slow. Thoughts appreciated...

 

[DrR]

They usually take a while to come on? Mine didn't come on for 2 months i think.

 

[Mike@Rentech]

Modify your car from standard spec, expect light to come on.
Ecu has done it's checks and finally decided that's somethings wrong hence light.
Major faults bring lights on it 2 driving cycles.

 

[unfortunately_french]

Ok so that's one person that has had it take a while to come on, what exhaust system are you running? I know that removing the cat is removing the cat regardless of the exhaust system used but just out of curiosity? Also have you managed to get yours to turn off? I know that blanking the lambda sorts it (but don't know how or what effect it has on the car taking a lambda reading) and have heard that sticking it on one of those RS tuner modules that everyone seems to talk about...

 

[Clarkey]

I decatted mine last saturday and light came on yesterday, so yeah can take a while.

 

[unfortunately_french]

Are you suggesting it's taken the ECU three weeks to work out that the CAT is no longer there lol? Surely this can't be the case. Don't understand what you mean about 2 driving cycles?

 

[Mike@Rentech]

Decats should be illegal in my opinion.
Remember you pay your car tax based on emmissions.
As to driving cycles etc I don't program the ecu's in the factory.
I just deal with all the s**t other garages can't fix day in day out at my place!

 

[DrR]

Reason i put my Decat on was because they increased my VED, so I increased my emissions!

 

[unfortunately_french]

Hmm I suppose that they kind of are in the sense that if they increase the emissions enough that the car would fail an MOT and not be roadworthy because of that part, Just taking the chance that a traffic cop wont pull me and smell the difference and get his emissions tester out. The road tax for my car is £235 i think...which is mighty steep in my opinion!

 

[DrR]

It's not tax anymore, it's VED.

 

[unfortunately_french]

Ok well whatever it is, it costs too much and there's too many potholes...but let's not go off topic. Maybe i'd get a sports cat if they weren't the same price as the whole system lol so any thoughts about getting it off without using an rstuner?

 

[Mike@Rentech]

Turn light off it will come on again, put cat back on bunnies happy trees will grow and the whole world will be a better place. LoL
If you want a decat with now warning light take panel apart remove led job done.

 

[unfortunately_french]

Yeah I did think about doing that, I thought I'd have to take the whole dash off though as I did it before with an ABS light on a different car . Mike your wish will come true, the CAT will go back on.....for about an hour in june when my MOT is due lol

 

[Mike@Rentech]

Haha

 

[DrR]

They called it VED so they don't have to fix the pot holes lol

I've heard if you leave the sensor out of the decat, and bung it up, the light doesn't come on.

Mike knows lot more than I do though!

 

[unfortunately_french]

They called it VED so they don't have to fix the pot holes lol

I've heard if you leave the sensor out of the decat, and bung it up, the light doesn't come on.

Mike knows lot more than I do though!

Yeah this is what I said earlier up the thread about blanking the sensor (bunging it same thing) but I think that means that the sensor is no longer taking a reading from the exhaust gases and the ECU relies on that info for the car to run well iirc which is why I didn't wana go down that route. I'm cheesed off because for 3 weeks my car has had a decat and no emissions light and then earlier when actually driving slow for a change it randomly comes on

 

[Chris_786]

Mine was about 1K miles after I put my decat on it. Chill out dude.

 

[Greeny.]

Never had one on in my old 172 after 3 years of a de-cat!

 

[unfortunately_french]

Mine was about 1K miles after I put my decat on it. Chill out dude.

Im cool as a cucumber dude, i said i was cheesed off thats all lol

 

[unfortunately_french]

Never had one on in my old 172 after 3 years of a de-cat!

*jealous*

 

[hipwell]

The rear lambda (one in the cat) does nothing at all towards the running of the car, it just takes readings.

So yes you can take it out and use a blanking plug but this still won't guarantee the light doesn't come on as the lambda will be getting extreme readings from air which the ecu may pick up on.

When I used to have my decat I couldn't get the lambda out of the cat so I just left it unplugged and blanket the hole in the decat. Car ran fine and the light came on but honestly guys why does everybody hate on a little led light ?

What I did notice though is that after gray remapped my car with the Rs tuner the light never came back on

 

[Munson]

How do people handle insurance with a decat? I want one but I'm concerned about not being insured.

 

[Chris_786]

"Exhaust system changes" is the correct term.

Goes down as exhaust - other.

 

[mark123]

Decat won't have any significant effect on carbon dioxide emissions which is what the tax is based on, it is pretty much equivalent to MPG. In fact it would make it emit less carbon dioxide as its main purpose is to change carbon monoxide to carbon dioxide.

 

[Munson]

"Exhaust system changes" is the correct term.

Goes down as exhaust - other.

Yeah but I'm talking about the validity of the insurance? How many people actually declare a decat specifically? I have read that it's a legal grey area. Not having a go. Just interested. When the insurance assessor sees my car upside down on the back of the lorry, and notices there's no cat, I'm humped. No?

 

[TimR26]

How do people handle insurance with a decat? I want one but I'm concerned about not being insured.

My insurer had no problems with it but probably varies from company to company whether they'll allow a decat.

 

[Ol’ Tarby]

Mines been on nearly a year and still had no light come on

 

[unfortunately_french]

Ok guys, I don't know why it bothers me maybe it's just the fact that it looks better without the light on or the fact that people ask why the light is on when they get in the car. A remap is the next thing on my wish list so i'll get that done and maybe it will sort it. I'll probably blank the lambda hole on the cat and cable tie the sensor up in the mean time and see if it makes a difference. As regards to insurance, if you don't tell them and have a crash just be sure to get the car recovered to somewhere you can put the cat back on before the guy from insurance comes to inspect. That wouldn't explain the rest of the stainless i've got on there though