Xantia Knock sensor location (?)

VertVega · Unread post by **VertVega** » 20 Nov 2010, 20:51

This is a general question. No problems with the knock sensor

I have seen knock (pinking) sensor in ebay list and I noticed that I have no idea where it is connected

Can you describe the location please?

Pic of the sensor from ebay,

Deanxm · Unread post by **Deanxm** » 20 Nov 2010, 20:56

it will be fitted on the front of the block , usualy obscured by the inlet manifold or ancillaries.

D

VertVega · Unread post by **VertVega** » 20 Nov 2010, 21:16

That's why I haven't seen/noticed it so far

Thanks.

Citroenmad · Unread post by **Citroenmad** » 20 Nov 2010, 21:21

DickieG was selling one of these at the national rally this year, i couldn't work out what it was. I was surprised when he told me, and interesting sensor.

VertVega · Unread post by **VertVega** » 20 Nov 2010, 21:28

Is it also in diesel models?

Citroenmad · Unread post by **Citroenmad** » 20 Nov 2010, 21:35

No, i dont think so.

Deanxm · Unread post by **Deanxm** » 20 Nov 2010, 21:36

no, only petrols, it just allows the ecu to run with the ignition so advanced its always on the edge of pinking but not quite it also means you can run a lower octane fuel without risking detonation. if pinking or pd starts the knock sensor detects the vibrations and turns them into an electrical signal to tell the ecu to retard the ignition timing.

Very clever use of old technology as the sensor is just a very sensitive low output piezo ignition really.

D

addo · Unread post by **addo** » 20 Nov 2010, 21:55

Xantia petrol engines discontinued the knock sensor in very early 1999. The plug is still on the harness, but no provision made for it in the ECU software.

Mine is like this; I've wondered what might happen if one were connected in.

Deanxm · Unread post by **Deanxm** » 20 Nov 2010, 22:05

Interesting as i thought they were only really used on turbocharged engines for obvious reasons, i have to admit ive not seen one on a nasp engine but that could be because i wasnt looking, i dont know.
I wonder why they would stop using them.................

D

addo · Unread post by **addo** » 20 Nov 2010, 22:37

They went to feedback from the sparking circuit. It's apparently seen as a better telltale of prevalent conditions inside the cylinder.

Deanxm · Unread post by **Deanxm** » 20 Nov 2010, 22:41

i think a google is in order here.................

D

Unread post by **CitroJim** » 21 Nov 2010, 07:46

The sensor is in fact a piezo microphone and it really does listen for a knocking noise!

Adam, I'm surprised it was deleted on later models...

Fact is, running an engine with the ignition advanced as far as the prevailing conditions will allow helps both with power output and and fuel economy. The knock sensors allows that and goes a way to explaining why an engine so equipped runs a little better on premium fuel...