Fuel Consumption & Changing Front 02 Sensor

[NA84WA]

Hey Guys,

I have noticed a higher fuel consumption lately. I have had the car tuned and a PHAT DP installed. A couple of tanks after the tune the car was getting about 550km per tank of fuel with a consumption of 10.2L per 100km, which is what it was getting before the tune so no change in ecomony. Now the car is getting about 420 per tank with 12-13L per 100km. Which shouldnt really be the case as my driving style hasnt really changed.

My question is could the front 02 sensor (A/F sensor in manifold) be on its way out and if i change it will the fuel ecomony improve? Ive had a CEL light and the code was P0420 which is to do with the cat converter and that is correlated to the rear sensor. I realise the front and rear sensors communicate but from what i have read it seems the rear is only to check cat efficiency. The code was cleared by the tuner and parameters increased so the CEL wouldnt occur again.

If anyone has had any experience with this sort of stuff that would be much appricated!!

Thanks guys

[Dropz]

P0420 is common with these cars, changing the parameters should keep it in check.

As for the higher fuel consumption, it may be due to the changed parameters. If nothing else has changed then get the parameters reset and see if it changes back.

[parso_rex]

Its unlikely that the sensor has failed and it will most certainly be the tune.These sensors are completely different to the usual wide-band sensors found on most other vehicles. Perhaps the tune still has a very rich mixture up top and with you now spending more time on boost your economy suffers.
As for the 0420 error code this is something that should have been removed in the tune so its never an issue, its an easy thing to do involving single mouse click
M