2000 Xantia 2.0 - which octane?

[MortyDK]

Dear all,

I have just acquired a used Citroën Xantia 2.0 16v, first registered in the year 2000.

The original instruction manual didn't come with the car. I have tried to google which octane the car needs, but without luck.

Does this car need 95 octane petrol? Or can I safely drive on the cheaper 92 octane as I've been used to so far?

[Harry1975]

i should say on the filler flap,not the cap . my 97 1.8 16v is 95 if that helps

[xantia_v6]

The engine has a knock sensor, so will adjust the timing to suit either grade of fuel. It should be a few percentage points more efficient on higher octane, but as they say, your mileage may vary...

[Harry1975]

how do you adjust a knock senor ?

[CitroJim]

how do you adjust a knock senor ?

You can't, it does it automatically. It actually listens for the sounds of the engine knocking and retards the ignition timing until it stops. All fully automatically. Hence why it can compensate for different fuels.

The knock sensor is just a microphone attached to the engine block. As simple as that!

[MortyDK]

I had an older Xantia before -- a 95 with a 1.8 engine. When I accelerated briskly, the engine would sometimes pull un-evenly, i.e. the engine would audibly stutter a bit, and the car wouldn't accelerate smoothly. This only came when I pushed it a fair bit, and usually in warmer weather.

Is that related to the octane being a bit too low for the engine, or is it something else?

Thank you,

[Harry1975]

thanks for info on knock senor , i thought that was the case, i know for sure now cheers

[MortyDK]

This is a great forum! Thanks for the answers.