Deadly Aura

I have fitted the decat pipe, was told that the light shouldn't come on but it has.

What can I do!?

Thanks

Ben

MSC

Did you screw your O2 sensor into it? Which decat is it?

MB

Lambda spacer needed.

markforrester99

Dont worry about the light too much, it wont effect the car.

You need to buy some spark plug anti foulers. I opted for two and screw them into the 02 sensor boss on the decat and then screw the O2 sensor into that.

http://www.ebay.co.uk/itm/BLOX-CEL-F...item2ec1f5dc7c

I brought an invidia decat thats supposed to have a CEL fix built into it but i didnt bother taking the risk of having to go underneath the car again so i just fitted the two foulers as well

Deadly Aura

Apparently its an invidia one. The sensor screws into the side/top. Thanks for the link Mark, I will have a look. Had the devils own job getting the sensor out, luckily the thread wasn't too damaged and its managed to screw into the decat. Hope the item you listed above sorts it. I know it probably no problem with the light on but it bothers me, and it also means that if something else crops up I wont know because the lights already on.

Mark, what are spark plug anti foulers? Not heard of them, what do they have to do with the lambda sensor?

Thanks,

Ben

PhilipGB

They move the sensor away from the exhaust flow I'm guessing reducing it's reading. Some people also stuff wire wool in the spacer.

markforrester99

Yeah basically what happens is you have the two O2 sensors, the first one in the manifold is for fueling and the second one is to check that the cat is working efficiently. If you secure the Cat 02 sensor into the decat then it will see no change in the emissions and bring up the check engine light to warn that the CAT might be passed its best. By fitting some spacers like the one on the link i posted you move the sensor outside of the direct exhaust flow so it has a hard job actually reading whats going on emission wise. It should never light up again if its spaced out enough.

Glad you got everything sorted in the end!

TTS Performance

So how are you adjusting the fueling to stop it running lean. Removing the Cat reduces back pressure by around 20%. The closed loop Lambda monitoring goes open loop on full throttle so you will lean out terribly. Not good for your engine.

Deadly Aura

TTS
Thats interesting. Not doing anything. Sounds like it might be a better idea to get a hi flow cat then eventually.

Can you explain more about how that works and why it goes lean?

MB

TTS, that info is not entirely correct.

I've seen a lot of NA S2000s dynod, and AFR only becomes an issue if you have a lot of breathing mods. Running a decat alone will come nowhere close to running the car lean.

In fact you need a good intake, header and decat to run into high AFRs. You will not lean out terribly.