I'm trying to replace the lambda sensor on my 1994 55SX, as I reckon thats the cause of my engine fault (injection light comes on at high speed & reduces rev limiter to 4500rpm), but I can't find a spanner that will fit it and leave enough clearance round the downpipe. Any special tool/trick to shift the sensor?

FIAT: Fix It Again Tomorrow...

I'm told it's an 18mm job exactly the same size as a spark plug.

all things must pass.

Hi.
Disconnect the wiring connector from the front of the engine and get the car on axle stands as it is easiest to get at it from underneath. You will need to either buy the correct spanner for the job or use a slotted socket to remove the sensor as a flying lead remains attached to the sensor after it is removed.Sorry don't know the size! Watch out you don't damage or mess up the probe as this is easy to do and the thing is sooo delicate.
[xx(][xx(][xx(]

Barnsley Tyke.

No joy using spanners - I can't get them to stay on the nut! It's a 21mm on mine, although I had to hammer the spanner onto it (rust!). I'm thinking of hacksawing the body of the probe off to leave just the nut bit, then I can fit a 6-sided socket on it to undo the damn thing.
Since the probe is dodgy anyway, would disconnecting it at the wiring connector make any difference to the running of the engine?

FIAT: Fix It Again Tomorrow...

Hi.
If disconnecting the Lambda wiring makes no difference to the running of the engine then why bother having one?..........why not disconnect it and see what happens..........THEN use a nuclear warhead or whatever is your preferred method to get the thing out.......put something on the thread of the new one to help get it out the NEXT time you need to, before you fit it.....but not on the probe ..or else.............[}]

You'll still need the right tool to screw the new one in without damaging it and it would be nice to apply the right torque to the thing as well!............why not get your hand in your arse pocket and get it done right

Barnsley Tyke.

A little less sarcasm please, Derek! [8D]
Major probs are:
(a) The bloody thing's well seized with rust so needs immense torque to shift it;
(b) The downpipe shape makes it impossible to get a spanner onto the nut properly in order to apply the above immense torque;
(c) I can't find a deep enough socket, never mind a slotted one!
Nuclear warhead, now that's an idea...

FIAT: Fart In A Tin

Can I recommend a lot of WD40 and a garage mechanic with the right tools.

Well said Evil-Punto......a good mechanic with the right tools (which means "hand in arse pocket" i'm afraid) looks like the only way out if it is in as tight as you say it is........go for it and put the cost down to experience.........[8][8][8]

Barnsley Tyke.

Hi again.
Sorry to sound sarcastic....not my nature REALLY but you could always replace the downpipe et al....eh?...(OUCH!)[^]

Barnsley Tyke.

had to remove mine last week to change the clutch (gearbox out) and it was tight.

used wd40 and applied a little heat to the downpipie using a blowtorch plus an open ened spanner that fitted real snug. once warm it came out pretty easy.

need to take care not to burn anything combustible or to apply heat to either the sensor or cables.

i could get the cables off, so a socket wouldnt have worked.