Can anyone tell me where bank 1 sensor 2 o2 sensor is located on my 1.4 fiat grandpunto jet black 2
Good morning Martin. As I've no idea how much you know about this sort of stuff here's a picture of a typical O2 (lambda) sensor:
This is actually one I removed from my boy's Vauxhall Astra, but they all look very similar.
There are two sensors on most modern 4 cylinder petrol engines, one will be screwed into the exhaust before the Catalytic converter so it can "sniff" the exhaust gasses directly exiting the engine and the second will be directly after the Cat. Bank 1 sensor 2 will be the post cat sensor so the second one I just mentioned. - Sensor 1 is always pre cat and sensor 2 post cat. The "bank" bit becomes relevant if you have an engine which is not "in line" for instance maybe a V6 or V8 or maybe a "Boxer" type like the Subaru flat fours. Other types also exist - Porsche flat 6 for instance.
Is your engine the 8 valve 1.4? If so it will be very similar to the exhaust in my Panda so I'll now post a few pictures which may help you. Here's a top down view of the front of the engine. The radiator is on the left and the exhaust is hidden behind the aluminium heat shielding but you can see the white cable going to the top sensor (pre cat so sensor 1) and if you look right down to the ground, just in front of that thick black water hose with the "jubilee" clip, you can just see the post cat sensor and it's wire (post cat, sensor 2) sticking out of the side of the down pipe where it starts to bend under the engine:
Here's a close up of the Pre cat (Sensor 1):
and here's one of the post cat (sensor 2):
Hope that all helps.
It can be very difficult to remove an oxygen sensor if it's been untouched for a number of years so give it a really good soaking with release oil and let it soak in for a while before you start. Some are so severely corroded into place that they rip out the threads as you try to remove them (special taps can be bought to try to clean up the thread if not too badly damaged) and I've even had one which ripped the whole threaded fitting out of the side of the pipe instead of unscrewing. You can buy special sockets to tackle the job but if it's really tight, and you're fitting a new sensor so don't need to save the old one, it may be best to cut the wires off and use a deep single hex socket to remove it. If it's really tight and you don't think it's going to move without doing damage it's probably best to get a garage on the job as they will likely have an Oxy Acetylene torch they can use to apply some extreme heat which will usually shift it.
A useful thing to know is that our Panda, (and I think all the 8 valve engines?) use the same sensor for both pre and post sensors so you can swap them over for reasons of fault elimination. The pre cat sensor has a significant roll in engine management (trimming fuel mixture) whereas the post cat sensor does very little except monitor the exhaust gasses exiting the cat for emission purposes so won't really affect engine running. Of course both sensors will light up the engine light on the dashboard if they either fail or detect exhaust gas content outside expected parameters.
A couple of quite common failures are for either the electrical connector plug to loose connections internally (unplug it and have a good look inside for corrosion or the supply voltage to the heater element in the sensor to fail either due to a problem in the electrical plug or a break in the wiring. Of course the wiring is subject to engine vibrations so fatigue stressing in the wires can cause internal breaks in the wires (inside the insulation) which can be difficult to find. I'd say a wiring or connector problem is just as likely to be encountered as a failed sensor so never just fit a new sensor without checking for continuity problems first (unless you have a spare sensor just sitting doing nothing!
Good luck. please do let us know how things pan out?