Hi Guys,

I put a berk high flow cat in about 2 years ago which is now rattling, since I don't want to buy a new cat every 24 months I've just taken delivery of a japspeed decat. I can't decide what to do about the inevitable CEL.

I know I can get the extender fix, which should stop it coming on and if not I cant stuff it with wire wool and that should sort it. However my concern is that the car will still over fuel even if the CEL isn't being triggered.

I've also see extenders that have a mini cat in them just for the O2 sensor, and while that seems like a great option it's about £60!

What I'd really like to know is, could the car still be over fueling because of the decat, even if the CEL isn't coming on?

If so, how could I find out (dyno?) and what could I do about it (remap?). I guess if the answer to these question is yes, yes and yes, I should bite the bullet at get the £60 mini cat extender.

Thanks

 

Fitting a decat will make your car run leaner at WOT, the second O2 sensor is just there to make sure the cat is working it has nothing to do with the fueling.
It's the first O2 sensor before the cat that measures A/F and helps the ecu to adjust the fuel on part throttle.

 

Just get one of these.....
http://www.ebay.co.uk/itm/TEGIWA-O2-...item5d4f3fa702

If you look around you can find them for less than £10.

Reset the ECU and the Cell is clear.

As for running Lean, take you car to a garage that can monitor live AFR and have then conduct a road test.

 

^ Blox cel eliminator from Tarmac Sportz in the Traders section for £8.95 works great

 

Would Be interested in your old one

 

Thanks for all the input guys, I didn't realise that the second O2 sensor is for cat check only! Other threads have given me confidence since the decat is the only airflow mod I've done, AFR will be OK.

@noodles, I'm going to hang on to the HFC in case I need to refit it for an hour once a year

 

Thanks anyway