Xantia V6 broken exhaust (update: and rough low rpm running)

[addo]

Item 7706 in the harness diagrams; plugged directly into the Hydractive ECU.

Where's me donut?

[Mandrake]

Well......item 7706 goes to pin 11 of the ECU, which is "Braking sensor signal" according to the Hydractive 2 training manual. This is a pressure switch attached to the front brake lines which is normally closed and goes open circuit when the front brake pressure exceeds 30 bars triggering an automatic switch to hard mode during hard braking.

That switch also only exists in Series 1 Xantia's and was deleted in Series 2. (It will always report CLOSED on a Series 2 Xantia on the Lexia regardless of brake pressure)

Now maybe they have re-purposed pin 11 for a different purpose on the Series 2 - if so I haven't seen any information about that.

Certainly on a Series 1 Xantia there is no ECU pin unaccounted for which would be free to run to the priority valve pressure switch.

[Mandrake]

My oxygen sensor has arrived, however I'm not quite sure what the little packet is that came with it ?

Is it graphite to put on the threads ? It doesn't really show in the picture but its a kind of gold/brown colour, not black, and somewhat granular. I know you're not supposed to grease the thread on an oxygen sensor with normal grease as it can poison the sensor or block the tiny ports that sample ambient air, but am I meant to put this graphite like stuff on the thread when fitting ? Also, the cable looks rather short to me, but perhaps I have misjudged the length of the original ?

[Ben82]

Simon, I believe it's Anti-Seize:
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(took me a while to find that video, but knew I watched one recently with replacing an oxygen sensor )

[addo]

It's copper grease. Meant for the threads of your sensor, but you are welcome to use otherwise at your own risk...

[Mandrake]

Ah that's what it is. I've never used copper grease before so I wasn't sure what it looked like. Cheers.

[lexi]

I've never used copper grease before

That means that my Son skyped me this morning from a totally different Planet.............New Zealand

[Mandrake]

Yes it is a different planet - a planet where there is no salt on the roads and the undersides of cars aren't covered in a layer of rust in mere months. A planet where you can remove 10 year old drop links without a hacksaw or grinder simply by applying a spanner and allen key, and where rear suspension arm calipers don't rust and go wildly out of alignment... Although I'm aware of copper grease I've never needed to do a job back home that required it...

[addo]

Il est utile. Vous l'appliquez modestement à vis de culasses lors du remontage.

[CitroJim]

Although I'm aware of copper grease I've never needed to do a job back home that required it...

Aah great See how we're educating you Simon..

We Pommies live on the stuff and have tins of it delivered daily here - it's what keeps our cars good...

[lexi]

UK.......the country of Challenges. Rust, Rain and Recession Coppaslip is also good for decorating fairy cakes and giving them to nosey neighbours

[myglaren]

Although I'm aware of copper grease I've never needed to do a job back home that required it...

Aah great See how we're educating you Simon..

We Pommies live on the stuff and have tins of it delivered daily here - it's what keeps our cars good...

Indeed, and it makes a nice alternative to Marmite on toast.

[addo]

Awfully quiet in here... I reckon the OP has traded in the V6.

[CitroJim]

Awfully quiet in here... I reckon the OP has traded in the V6.

Funny you should say that Adam, I was just thinking we haven't had an update from Simon for a while..

Mind you, I believe he's like me - totally pre-occupied with work in the week and can only play cars at the weekend...

[Mandrake]

Yep, that's about it Jim... I don't really even get a chance to drive the car during the week, let alone work on it. It gets driven maybe 2, 3 times at most during the week and only for short trips. (I can really notice the brake discs rusting up through lack of use in fact, they make a lovely grinding noise when I first start using them again)

Part of that is me avoiding any unnecessary long trips when I don't know what kind of fault I'm dealing with. The last thing I want to be doing is long high speed trips with a misfire and risk melting the cat. (if it isn't already damaged) I don't think its misfiring, but until the performance is back up to normal I can't be sure, so I'm playing it safe.

If I had a lit and heated garage I might do a little bit of tinkering during the week but I don't which means that at this time of year working on the car is out of the question except at weekends, and last weekend was a wash, literally.

I'm waiting patiently for pay day before I can proceed with anything as funds are now zero, I have my oxygen sensor at the ready, I plan to buy that exhaust system off ebay (how does yours look by the way Jim ? I assume it has arrived now) the only snag really is that I haven't been able to sort out an adaptor from the oxygen sensor socket to my gauge - I really want to measure the back pressure before installing the new oxygen sensor and before blindly changing the exhaust but I can't locate an adaptor or the parts needed to make one.

The cheapest purpose built back pressure gauges are around £120 - twice the cost of the exhaust, so that is obviously not going to fly when its most likely a one use tool for this car...

Anyone have any further thoughts on the back pressure gauge adaptor ? All I really need is a threaded adaptor that fits the oxygen sensor socket with a compression joint to a long copper pipe - the one Addo linked to earlier on ebay is the sort of thing I need but I don't think it has the right thread for the oxygen sensor socket.