Simon's new Xantia V6 and Leaf blog

[Mandrake]

I think Simons problem with the emissions was that they DID overrev it ... and then failed it! It'll sail through a second time, they'll be too embarrassed to do otherwise.

Yes, the emissions were absolutely fine - it only "failed" because the tester over-revved it during the test then was too incompetent to read the report, realise their mistake (an easy enough mistake I'm sure when it was only 10rpm too high and was probably being monitored on the dashboard tacho) and re-run the test, instead of handing the botched test report to the customer...

Anyway, it went back for a re-test today and passed no problems at all. Not even a murmur about the hand brake, and the emissions result was even better this time - fast CO of 0.03%, HC of 12ppm and idle CO reading of 0.00% (less than 0.01% I assume, not truly zero) - can't ask for better than that from a 17 year old V6!

The only advisory is a small exhaust leak at the joint between the CAT and the centre silencer (the bane of my existence) which has been puffing out carbon onto the pipe, so I'm going to order a new clamp and pull it apart to see why it's leaking even though AFAIK the flanges are OK... maybe the fitting of the joint and/or sealant wasn't quite right when it was last fitted.

Anyway, the pressure is off, MOT'ed for another year, meaning another Xantia lives for another year. Now I can get on with a few other jobs to keep the perfectionist in me happy, such as lower ball joints, exhaust joint, cruise control etc without worrying about a looming MOT...

BTW the mystery creaking noise that I talked about a few pages ago that happened when turning the steering or stopping/starting seems to be completely gone now - don't know what it was, will possibly never know...but I suspect now that it has new hand brake cables I won't hear it again...

[Stickyfinger]

GJ,,,,nice to have a sheet of paper to prove something these days....I miss my Tax Disk, I keep thinking I'm guilty !

[Hell Razor5543]

I think Simons problem with the emissions was that they DID overrev it ... and then failed it! It'll sail through a second time, they'll be too embarrassed to do otherwise.

Yes, the emissions were absolutely fine - it only "failed" because the tester over-revved it during the test then was too incompetent to read the report, realise their mistake (an easy enough mistake I'm sure when it was only 10rpm too high and was probably being monitored on the dashboard tacho) and re-run the test, instead of handing the botched test report to the customer...

Anyway, it went back for a re-test today and passed no problems at all. Not even a murmur about the hand brake, and the emissions result was even better this time - fast CO of 0.03%, HC of 12ppm and idle CO reading of 0.00% (less than 0.01% I assume, not truly zero) - can't ask for better than that from a 17 year old V6!

The only advisory is a small exhaust leak at the joint between the CAT and the centre silencer (the bane of my existence) which has been puffing out carbon onto the pipe, so I'm going to order a new clamp and pull it apart to see why it's leaking even though AFAIK the flanges are OK... maybe the fitting of the joint and/or sealant wasn't quite right when it was last fitted.

Anyway, the pressure is off, MOT'ed for another year. Another Xantia lives another year. Now I can get on with a few other jobs to keep the perfectionist in me happy, such as lower ball joints, exhaust joint, cruise control etc without worrying about a looming MOT...

BTW the mystery creaking noise that I talked about a few pages ago that happened when turning the steering or stopping/starting seems to be completely gone now - don't know what it was, will possibly never know...but I suspect now that it has new hand brake cables I won't hear it again...

I wonder if the last point (the creaking) was because it had not been driven that much prior to your ownership, and so a little bit of surface rust built up (not unlike that which appears on brake disks when the car has been stood for a few weeks), and was creaking as it was wearing off. Now the surfaces are clean they move smoothly without complaint.

Well done on the MoT, although it is doubtful that it should have failed in the first place!

[Mandrake]

I wonder if the last point (the creaking) was because it had not been driven that much prior to your ownership, and so a little bit of surface rust built up (not unlike that which appears on brake disks when the car has been stood for a few weeks), and was creaking as it was wearing off. Now the surfaces are clean they move smoothly without complaint.

I don't think so, because for the first 6-8 months that I had the car there was no creaking noise at all. It appeared very suddenly, seemingly out of the blue about 2-3 days after I drove through some massive flooding at 70mph on the motorway - deep enough flooding that it nearly pulled the car off the road and completely covered the windscreen, reducing my visibility to zero until I got out of the water...

I'm pretty sure water - a lot of water - got up into places that it shouldn't be, and it wasn't until a spell of sunny dry weather a few weeks later that the noise started to subside a bit, but only fairly recently - a few months later had the noise subsided to the point where I realised I was no longer hearing it... (when you get used to a noise it takes a while to realise it has gone!)

Well done on the MoT, although it is doubtful that it should have failed in the first place!

Thanks - I agree it should have passed the first time too, however all's well that ends well - I had already bought the handbrake cables anyway and fully intended to fit them soon after the MOT, I just wasn't expecting to do them in a hurry over a long, mostly rainy weekend before an MOT retest! I'm glad they're changed - the handbrake does work better now and that is one less thing to fail in the future...

[CitroJim]

Excellent news on the MOT Simon, even though it should have gone through first time! Main thing is that it now has...

Good for another year now!

[Mandrake]

In amongst the MOT excitement I forgot to post about an odd behaviour I noticed on Friday morning...

In the last couple of months I've noticed that the performance of the engine isn't always what it should be (yes, here we go...) where it could be really zippy one day and mediocre the next with no real apparent cause, so I'd decided to do a battery off reset with the battery disconnected for 15 minutes. After I reconnected it I didn't actually start it for a couple of days as we didn't need to go anywhere in the car.

The day I next started it we'd had really heavy rain over night, and I mean REALLY heavy, absolutely pelting the loft windows in the upstairs bedroom enough to wake us up several times...

Anyway I started it up to go somewhere and there was a massive misfire such that I could feel the engine really shaking - bad enough that my other half who never notices things about cars said "that's really shaking badly, is there something wrong ?"...

Some of you might remember a while ago that when I changed the spark plugs and spark plug leads and had the mishap where the spark plug well got filled with coolant it misfired really badly for a few minutes the first time I started it up and gradually came right - well it was behaving exactly the same this time with a really bad misfire of 1 maybe 2 cylinders.

I was in a hurry to get somewhere for an appointment and thinking that there might have been a bit of water that found its way into the engine bay the night before I figured I couldn't really do much except to drive it a bit to see if it would clear, so after 20-30 seconds of idling and continuing to misfire I set off, and by the time I had got about 50 metres up the road the problem vanished. By the time I stopped at the next junction it was idling perfectly and the performance also seemed fine - if it was still down a cylinder or two on power by that point I would have really noticed it!

So, what the heck happened, and is it the same thing that happened last time after changing the spark plugs ? The way I see it, there can only really be two possible explanations:

One is that water was affecting the ignition system - in both cases water was involved. In the first I'd accidentally filled one of the spark plug wells up to the top with coolant while changing the expansion chamber, (although I did very carefully clean it out before removing the spark plug, and the spark plug and spark plug cassette was being replaced anyway, so it was all nice and dry before reassembly) and in the second case there was extremely heavy rain that perhaps found it's way in through one of the many scuttle cracks. Unfortunately I was in a hurry and didn't have time to pop the bonnet and look for evidence of water ingress.

The other possibility is that the battery off reset triggered it - in both cases the battery was disconnected long enough to reset the ECU to all default parameters. My line of thinking here is that if the engine is running a bit lean (which I do have suspicions of on this car...) due to for example low fuel pressure, the ECU may have been compensating for that with the data learnt from the oxygen sensor, however if you do a full reset the initial start after that will be purely factory preset fuelling - it takes around 60 to 90 seconds for the oxygen sensor to start working on a cold start and if it has forgotten any previously learnt fuel trim that might have been compensating for a lean mixture it would suddenly be trying to start the engine on a lean mixture, thus a lean misfire.

As soon as the oxygen sensor comes online the ECU will notice straight away that it is running very lean and quickly make corrections to the mixture to bring it back to normal - thus the misfire which started off very bad to the point the engine was shaking suddenly goes away. Which is pretty much exactly what happened. It wouldn't have been any more than 2 minutes before it was running normally again and it hasn't misfired again since.

IMO if it was water in the ignition system it would have taken a lot longer than 2 minutes to disperse it to the point that it could go from a bad misfire to normal running.

The fact that the emissions test was absolutely perfect the following day (first attempt at the MOT) and again today suggests to me that there isn't a mixture imbalance between cylinders. Any imbalance like an individual lean cylinder caused by an intake runner leak will raise CO and HC readings as the excess oxygen from the lean cylinder will be read by the oxygen sensor. This will cause the ECU to attempt to compensate the mixture in the process causing all the other cylinders to run richer than normal, thus higher HC and CO. In fact to get HC as low as 12ppm you need to have really good balance between the cylinders...

On the other hand if the fuel pressure is indeed low, it won't really have any effect on the emissions reading because the test is performed at idle and at a constant 2750rpm at a light throttle - in both cases the ECU will be in closed loop mode, using the oxygen sensor to compensate the mixture. So as long as the oxygen sensor is warmed up, the emissions will still be perfect. I know from empirical testing with fuel pressure on the old Silver V6 that this is the case and that the ECU has quite a large compensation range - and indeed that car ended up getting a 3.5 bar regulator fitted to it and then proceeded to fly through the emissions test.

I haven't been able to measure the fuel pressure on this car yet because all the seals in my fuel pressure gauge (especially the dump valve button seals) have decided to swell up and start leaking. (anyone know how to fix that ?) But I do intend to measure it soon. I have a number of different regulators (I think I still have 3 spare ones! ) and they all measure different in pressure with one of them as low as 2.7 bars, so they do seem to lose pressure with age. (The spring fatigues ?) The fuel pump is also conspicuously noisy too.

Although the pick up from low rpm and and with a light throttle has been really good on this car compared to the silver v6 it has always lacked a bit in the foot to the floor acceleration compared to the other car, (which is exactly where low fuel pressure would show up) so I think it's time to fix my fuel pressure gauge and do some pressure testing....

[Mandrake]

Here is the fuel pressure gauge by the way:



It's leaking through the clear overflow pipe (which should only dump when the button is pressed) AND out past the button itself!

It doesn't look very easy to get at the seals (I assume there are two) in the side section that goes to the button, perhaps impossible.

Another problem is that the seals in the "tyre valve" like safety cutoff valves in the hose sections seem to swell up (I assume) and block themselves off if exposed to petrol for too long - so I have to actually remove them to get it to work at all!

Is there any way I can service this gauge or am I best to chuck it and start again...

[CitroJim]

Defnitely not chuck it Simon, there must be a way to dismantle the dump valve or else just remove it totally..

The dump valve is not needed if you can tolerate a little spill when you disconnect.

[Mandrake]

Hi Jim,

I went to take it apart yesterday and discovered that all the threads were well and truly locktited.

The only one I was able to break the locktite on and get undone was the one that the clear hose pushes onto - this revealed the shaft for the dump trigger button, so on a whim I poured a little bit of light oil into the hole (some LT 71141 as that's what I had to hand ) on the basis that maybe the o-ring was dry and/or distorted and squeezed the trigger many times, then put it back together.

Presto, no more leak through the dump valve!

I used it to measure the fuel pressure - I've been noticing a bit of intermittent lack of oomph for the last few months (no-where near the problems I had with the Silver problem child, but enough that I can tell something is not quite right) so wanted to rule out fuel pressure.

Turns out the fuel pressure - at least on a cold engine, is absolutely fine. About 2.4 bars at idle with the vacuum hose connected rising to 2.9 bars with the hose disconnected. More importantly flooring the pedal with the hose disconnected should hold the pressure absolutely steady without any dip which it did, which says that the pump has plenty of delivery. (With the vacuum hose connected the pressure should rise from 2.4 bars to 3 when you floor it of course)

Furthermore I tested the ability of the fuel rail to hold its pressure after the engine is stopped - after 45 minutes it still had 2.6 bars of pressure in it which is absolutely spot on as well.

So unless there is a problem that only exhibits when it gets hot, I can't find anything wrong with the fuel pressure. I notice that the air intake temperature sensor has two lugs snapped off and doesn't sit in the housing properly any more so I will need to replace that, but I don't think that would have a major effect. An air leak around the o-ring of the temperature sensor could be the source of the strange air intake whine it has always had though!

[Mandrake]

In other news, Richard and I had a go at replacing the lower right balljoint a week ago in an effort to eliminate the rattle in the suspension on steering lock... and much to our chagrin it turned into a bit of a disaster.

Nothing went right and nothing wanted to come undone at all. We had the Clark impact driver that is well recommended by others, on it's first outing, and the Sealey ball joint removal tool, but do you think it would shift it ? Nope! Not a chance in hell... In fact it was so tight that the impact driver basically twisted the slotted ring around nearly doubling the width of the slot. Part of the problem there we think is that the teeth on the tool were not long enough to engage both levels of the slot, thus applying all the force on the one further from the hub. We tried plenty of heat, and also tried a good old fashioned breaker bar with a long pole while the hub was strapped down with a trailer ratchet strap and that also would not budge it.

In an effort to get better access to the joint to apply more heat we tried to remove the discs but the two brake carrier bolts that have to be removed before you can get the disc off also would NOT budge. Argh! With it by now being late afternoon and the rain and wind picking up and the prospect of a car off the road we somewhat sheepishly decided that discretion was the better part of valour and put it back together with the original joint, using only the new nut that came with the new joint and some fresh grease. Luckily we hadn't damaged the boot or overheated the joint, in fact the joint felt absolutely fine with no slack in evidence.

To get the heat shield back on I had to chisel off the ends of the now highly distorted lugs which means that there is now no driving edge left on the slots for any future attempts to get the joint out. So it is now 100% definitely a hub out of the car on the bench with vice and stilsons job...in fact in truth it might require a replacement hub as it may be nearly impossible to remove with the keying on the joint now destroyed...

Definitely one of those days where nothing goes right and you wonder why it is you "enjoy" lying under a car in the rain grunting and cursing for several hours..I think I should have stayed in bed that day...

On the plus side, it feels absolutely fine to drive afterwards (no worse than before that is, the rattle is still there) so I don't think we've damaged the joint, in which case I will be letting sleeping dogs lie and never attempt to remove that joint again, and won't be attempting the one on the other side either...

Also, after seeing the condition of the joint it has now made me reconsider the source of the rattle and the fact that it only happens on a right lock - I'm now starting to suspect the track rod end - in truth I should have replaced that first before the much more difficult lower balljoint. Lesson learnt!

Poor Richard probably waits in anticipation for the day that I visit with a nice easy job...

[CitroJim]

Excellent news on the fuel pressure gauge Simon That's an excellent time to hold pressure...

What a game with the balljoint I've never tried doing one in-situ. I always have removed hub complete and mounted it in my massive vice and used the tool with a four foot breaker bar.

Not had a lot of trouble with that method yet but it does involve more work initially..

[Mandrake]

All good on the car front.

A couple of weeks ago it was treated to an engine oil and filter change - the oil was well black and in need of a change...

This time I decided to go for 5 litres of fully synth Castrol Magnatec 5w-40 and a Bosch filter. I know not everyone here likes Castrol but I have always been partial to it. In the month or so before the change I had noticed there was sometimes a light "tapping" coming from the engine for up to 10-20 seconds or so after a cold start, not from the top end either.... That has completely gone with the oil and filter change. (I'm guessing the oil pressure was a bit slow to rise from cold - it certainly wasn't low on oil)

Last weekend I got around to changing the air intake temperature sensor - I previously mentioned it had two tabs broken causing it to fall out of place, seen here beside the new one:



With two of the tabs broken it was falling down on an angle causing the sensing tip not to protrude nearly as far into the air stream as it should, and also causing an air leak past the o-ring.

I had speculated that this might be contributing to intermittent low power as the air intake temperature reading has quite a big effect on the injection time, so an inaccurate reading could adversely affect the mixture. I was noticing that after I'd been driving for a while (or on a very hot day) and the engine bay had heated up fully that power and performance started to sag quite significantly, and that it ran markedly better first thing in cold weather.

I only half expected it to make a difference but it did! No more sagging power when it heats up. My theory is that the sensor was reading too hot when the engine bay was warmed up - any air drawn in past the leaking o-ring would be hot engine bay air (which can be very hot, exceeding 50 degrees) flowing right past the sensor tip, and also if the tip of the sensor had fallen most of the way down inside the tube its mounted in so that it's not properly in the air stream, it's going to tend to read the temperature of the plastic housing rather than the air flow itself - and that plastic housing also gets pretty hot.

Hotter air is less dense so the injection pulse is reduced when the air intake temperature reading increases, all other things being equal - but if the reading is falsely high compared to the actual air temperature going into the manifold (remember the sensor only measures the air flowing into the ICV bypass not the main throttle plate) then you will end up with a mixture that is too lean when the engine bay gets hot. Certainly fits the symptoms anyway.

As I have been wondering for a while whether the engine was performing as it should be (and it wasn't before I changed this air temperature sensor) after changing the sensor and noticing that it was performing a lot better I decided to be naughty and time the 0-60 time with a rather neat iPhone app called Dynolicious (David will know the one I mean ) and on a safe stretch of road which unfortunately has a slight rise towards the middle I measured 9.01 seconds. Depending on what figures you believe it should be 8.6 or 8.2 seconds for the V6 auto so I'm quite happy with that considering I was going slightly uphill, did nothing more scientific than plant my foot in sport mode, and the car is 17 years old!

Not only does it seem to be performing nicely now, the strange and annoying induction "whine" that has been there at around 2800rpm ever since I've had the car seems to be gone at last. (I think David remembers hearing this noise ?)

Clearly there was an air leak past the o-ring - I notice that the new one looks slightly bigger in diameter, as well as the unbroken clips holding it in position better, so it won't be leaking now. There was also a leak past the edge of the air filter when I first got the car - when I fixed that last year with a new filter the whine got a lot quieter (it was really bad before that) but it never went away - now it has gone completely.

So if you're ever trying to find a strange whining noise on your V6 check your air intake system for leaks - even a small leak is apparently enough to make a lot of noise!

I still haven't had a chance to tackle the cruise control yet as I have to make the time to hacksaw off and replace two of the bolts for the underneath rubber flaps before I can even get access to it, but I hope to do it before the winter as I really do miss my cruise control...

In other news the garage roof is nearly repaired (only guttering remains to be fitted) so I can start making use of it, and my mum is over from NZ for a few weeks starting Friday...

Oh and the house is still calling out for the kitchen and bathroom to be finished....

One more job I think I should do soon is the aux belt - that is looking rather cracked - does anyone have any recommendations for a source of a good quality aux belt for the V6 of the right size ?

[CitroJim]

Simon,

I'm just going to find a comfy chair, arm myself with emergency rations, alert my close family I may be unavailable for some time and then I'm going to read your latest post.... I may be gone some time whilst I read and digest it...

[superloopy]

I'd not stand for that Simon when he's sitting down [emoji1]

Sent from my LG-D855 using Tapatalk

[CitroJim]

Hi Simon, that's really interesting on the inlet air temperature sensor. I notice a lot I've seen have broken tabs and it's something I'll carefully check in my stock once my V6 Activa build nears completion...

I'm delighted it seems to have resolved an issue and as you say, when you think about it then it all makes excellent sense...

I use whatever Aux. belt comes along.. Dayco or Gates seem OK. Main thing is to keep a beady eye on them and replace them as soon as they look a bit iffy...

I apologise for my earlier comment, I was feeling very frivolous