Error codes - Page 1 - Boxster/Cayman - PistonHeads UK

I had 200 cel sports cats, along with new lambda sensors and a valved exhaust fitted to a Boxster 2.7 last week. After about 80 miles the CEL came on. Returned to the garage and the fault codes were 420 & 430 warm up below threshold. I spoke to Top Gear who were very helpful who said it rarely happens but they will send me some Lambda sensor eliminators and that would sort the problem out. I have the car booked in for a weeks time to have this done, in the meantime I obviously want to use the car. I have done some research and am finding a bit of a minefield! Some say don’t drive the car, some say it’s ok. The thing I’m concerned about is once the eliminators are fitted, is that a solid permanent fix, or is it just a trick to keep the CEL off, and could it cause future damage. Any help and advise is much appreciated.

My understanding is you space off the sensor so it reads less directly and this tricks the ecu as such. I believe you are ok to drive it in the meantime but if it was me I wouldn't be thrashing it until the spacers are fitted and the faults cleared.

Ok, thank you.

Why are you not getting the car remapped properly to match the new cats? Surely that would solve all the issues rather than bodging around them?

I would expect the fuel trims within the current ECU mapping to be able to compensate for the 200 cell catalytic converters. You can't beat a remap, but in this particular case I don't think it is necessary and I would simply add the lambda probe spacers if it was my car. Your car, money and choice to make though.

I've used the lambda spacers for the best part of 10 years. The angled ones work the best. A remap would be nice but isn't an absolute necessity.

Thanks for your replies. As a coincidence I’m visiting a Porsche specialist tomorrow with a Porsche drive group, so while I’m there I can also hopefully get some advice. I’ll do whatever it needs to get it right! Having spent 3.3k so far a little bit more won’t hurt. I love this motor and intend to keep it for at least another 3 years on top of the 4 I’ve already had it, and it is thoroughly mothered!

Forgive my ignorance, but if you adjust the lambda sensor mounts then isn't the ECU getting a non-true reading for the purposes of fuelling and therefore while the CEL won't come on the mapping is not optimal and you may be damaging the engine? I get that the ECU will adjust fuelling based on sensor data, but you're tweaking the source sensor readings.

It’s sounding like getting it mapped is the answer as you suggested originally, I’ll hopefully get some more help with this tomorrow and will update the post. Thanks.

Twinfan said: Forgive my ignorance, but if you adjust the lambda sensor mounts then isn't the ECU getting a non-true reading for the purposes of fuelling and therefore while the CEL won't come on the mapping is not optimal and you may be damaging the engine? I get that the ECU will adjust fuelling based on sensor data, but you're tweaking the source sensor readings. If it is the set downstream from the cat (which it sounds like) then it is just monitoring cat performance and plays no role in engine mapping. I think.....

Discombobulate said: If it is the set downstream from the cat (which it sounds like) then it is just monitoring cat performance and plays no role in engine mapping. I think..... Gotcha, makes sense, but I guess mapping could be affected if the car thinks it needs to do something to get the cats to be more effecient e.g. run richer/leaner whatever.

Twinfan said: Discombobulate said: If it is the set downstream from the cat (which it sounds like) then it is just monitoring cat performance and plays no role in engine mapping. I think..... Gotcha, makes sense, but I guess mapping could be affected if the car thinks it needs to do something to get the cats to be more effecient e.g. run richer/leaner whatever. Correct, the downstream lamda probes don't do anything to alter the fuelling. They are just there to check to see if the catalytic converter(s) are operating correctly. When catalytic converters were first introduced they only used to have one lambda probe fitted per bank not two like they have now.

The Porsche specialist said fitting the eliminators will work sufficient enough, I’ll also go through it with the garage next Tuesday. Thanks for all your help and advice on this.