(T) Barchetta emissions !!!

If the signal from o2 sensor voltage is swinging between around .2 v and .7v the mixture is correct.

Don't play parts roulette it's very expensive and doesn't really work.

You can't read o2 sensor signal wire with a multimeter , voltage changes to rapidly. You can use an oscilloscope type meter to view signal output.

You can possibly check the coolant temp sensor that sends signal to engine ecu.
There may be a separate coolant temp sensor for gauge. Don't be fooled into thinking ecu seeing correct temp as gauge shows correct temp if ecu and gauge have separate sensors.

If o2 sensor signal correct and you don't have misfire then your cat is not working.

I don't know which cat you bought but some cheap ones only last long enough to get you through one test.

What brand o2 sensor did you fit as replacement, was the old one faulty?

How do i measure O2 voltage ?

With an oscilloscope or graphing volt meter

Do you have a manual for your car showing where the sensors are located on engine?

Hello arnietwo,
I live in a small town in Guadalajara in the center of Spain. 3 weeks ago my 1995 yellow Barchetta past the ITV after several tries from a friendly inspector. My problem is also at 2000 - 2500 rev.. I was told that the problem could be some leakage at the exhaust. I remember that in the german forum I read sometime ago about leakage problems with the flextube before the catalysator.
Hope this helps you and when I check my exhaust I will inform what I found.

Regards Juan Carlos

Juan, muchas gracias, tuve un fugo tambien en el tercer parte del tubo de escape. Todo bien ahora.

Hello Arnietwo, happy to read that you found the leak and everything is fine again.
In the next weeks I will go under my Barchetta and try to find and solve the problem in mine.

Problems yet again with emissions at ITV.
Went 2 weeks ago and readings were
CO at idle 0.48,( max 0.5)
CO at 2500revs 0.41 (max 0.3
So failed on second part.
I checked my exhaust and thought possibly the connections between pipe after cat and muffler section wasnt tight so fixed that.
I went today,
CO idle 0.34
CO 2500, 0.54
So worse ??? He also said hydrocarbon was high at 160, but not sure what that means.
So any suggestions would be appreciated. My first thoughts are to buy new better quality lambda sensor, but not sure ??

Bought new bosch lambda sensor €90, fitted it and went again to test centre.
Readings this time,
At idle 1.00
2500revs 0.71
So worse again ????
Im getting a bit sick of these emission issues every year!!!
So annoying as the car is driving great !
Im thinking there has to be something more, other than idle control valve, cat, spark plugs, lambda.
Can anyone HELP ??

I feel for you, same problem every year with itv.

It drives me barmy that every day I follow some crappy old truck or bus straight out of the Flintstones kicking out more smog than a powerstation and somehow they have got a bloody itv sticker for this year, how do they get them through when little old barcky can't get through looking as clean as whistle?