WRONG.
It isn't simply unticking a box so the ECU stops looking for it...
While in basic terms, this is correct, the ECU is mapped specifically to suit the fact that there is a De-cat in place, eliminating the need for the secondary Lambda probe. Only utilising the primary for AF Readings.
The secondary lambda is purely there to confirm that the CAT is working, properly.
No-one/hardly anyone uses O2 sims or lamda spacers as it's not the right way to do things.....
There's a reason why people use K100/Kpro....
Not wrong, you untick a box which stops the ecu looking for the sensor that is no longer required due to there being no cat as you have said yes, obviously the ECU is remapped to suit whatever modifications you have, not just because you have a decat fitted. You map it to take into account the engine is breathing better overall and would still do this even if you left the cat in place and fitted other modifications.
The way you have worded the first part of your response implies that the stock setup uses both O2 sensors for A/F monitoring which is incorrect. You then correctly state the second O2 is just to confirm the CAT is doing its job.
Saying not to use an O2 sim or spacer is not the right way to do things is incorrect. All you are doing by fitting the Sim or the spacer is ensuring the correct sensor voltage is seen by the ECU. This has exactly the same effect as telling the ECU not to look for that voltage and if done right there is no reason why anyone can say this is not the right way to do it. When the O2 sensor is in place behind the CAT the voltage does not cycle up and down so much and therefore the second sensor outputs a different signal to the first sensor, this is what the ECU expects to see. If the CAT is removed it has the same effect as putting both sensors side by side which causes the signals to be almost the same, the ECU then thinks your CAT is knackered and this is what then brings the EML on. All you need to do to prevent the light from coming on is ensure the rear O2 sensor outputs a different less fluctuating voltage to the ECU, I believe from some recent testing I have carried out this voltage is around 0.45v and as long as the ECU sees that you will not get any EML issues.
I am not daft, I have fitted and remapped ECU's in various cars and know how it all works, you then copy a post from my other thread to prove what ? the only reason I am not sticking with the unichip is because the software is not available to allow me to remap it myself which Is why a Kpro is a good option, its nothing to do with me looking for more functionality at all, although I agree that is a bonus.
I thought the whole point of this forum was to help people out ? I think we all need to remember not everyone can afford to just go out and buy a Kpro and pay for a remap ! If people already have some other form of management fitted or wish to eliminate an EML due to removal of a cat then there are still other cheaper options available and this thread was purely to try and find out which method out of the cheaper options works the best ! Not to start yet another thread that leads to the generic answer of just go fit a kpro !
And just for the record, you all seem to say you MUST get a remap with a full exhaust system/header/decat fitted ? well I stuck my wideband on mine without the unichip fitted just to check the fuelling was still ok and it was well within spec, if anything its running a little on the rich side. I am in no way saying every EP3 will be like this, but mine certainly is and I have no lumpy idle or stalling at junctions etc.
Not trying to fight with anyone here, I am just trying to help out those people who cannot afford to blow a load of cash on a fully mappable ECU plus the tuning time !
