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

Tell us your ongoing tales and experiences with your French car here. Post pictures of your car here as well.

Moderators: RichardW, myglaren

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

You're up early for a Sunday Mike :) :lol:

addo
Sara Watson's Stalker
Posts: 7098
Joined: 19 Aug 2008, 12:38
x 4

Post by addo »

Books were cooked quite well. There were carbies made in Strasbourg, that said "Sidney" on the casting. I always liked that one.

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re:

Post by CitroJim »

addo wrote:There were carbies made in Strasbourg, that said "Sidney" on the casting.
A well-known suburb of Strasbourg Adam, famed for it's 'Carbie Quarter'...

User avatar
DickieG
Monaco's youngest playboy
Posts: 4896
Joined: 25 Nov 2006, 10:15
x 14

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by DickieG »

xantia_v6 wrote:The trick of clearing a fouled plug by holding the cap off the plug by a few mm works because the waveform is different, not because the voltage is higher.
I beg to differ Mike, the oscilloscope of the Sun MEA 1500 tuner I had displayed firing voltages and the spark plug with its lead pulled away by a few mm produced a far higher spike as the coil attempted to bridge the gap caused by pulling the HT lead away from the plug, the only difference in the waveform pattern of the relevant plug was the firing voltage being far higher. The waveform of the firing pattern does vary if some of the ignition components (such as spark plugs, points/condenser) are beyond their useful life as the start of the firing line doesn't have a 90°angle, being more of a 45°turn before it rises to the ultimate voltage.

If an HT lead/coil/rotor arm/distributor cap has poor insulation the firing voltage are very low to barely rising at all, if all cylinders have low voltages then the coil, rotor arm or dizzy cap are suspect, just one cylinder then the cap, plug or HT lead are suspect, this is of course provided the engine is in good mechanical order.

User avatar
xantia_v6
Forum Admin Team
Posts: 7469
Joined: 09 Nov 2005, 23:03
x 419

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by xantia_v6 »

The point is that the additional spark gap means that the rise-time at the plug is not constrained by the characteristics of the coil and HT leads, and can be much faster. Your oscilloscope (if connected on the coil side of the spark gap) won't see this, and anyway won't have the bandwidth to measure rise-times of a few nanoseconds. What you are seeing on the oscilloscope is mostly the behavior of the coil reacting to the spark, not the characteristics of the spark itself.

User avatar
Mandrake
Posts: 8196
Joined: 10 Apr 2005, 17:23
x 328

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Update: I now have two inlet manifold gaskets on order from Citroen, £2.50 each, should arrive in a couple of days. (so they say :roll: ) I decided to get two as I know I'll have to do the leaky cam covers at some point in the future so it would be silly not to get a spare gasket for that now.

I also have a new set of rear spark plug leads on order, I've managed to find some at quite a good price I think. Initially I was going to get them from ignitioncarparts.co.uk, but when ordering I noticed the £72 was excluding vat, so by the time shipping and VAT was added on it was going to cost me £95, and I'm already in the doghouse for the money I've spent on this car recently, so I did a bit more searching and came up with this:

http://www.mister-auto.co.uk/en/ignitio ... _g685.html" onclick="window.open(this.href);return false;

£60 but there is also a 35% off promo code at the moment (don't know how long that is lasting) meaning that the final cost including shipping and VAT is only £46.39. Not bad! :) Hopefully this company are legit, I guess I will find out soon.... ;)

addo
Sara Watson's Stalker
Posts: 7098
Joined: 19 Aug 2008, 12:38
x 4

Post by addo »

Yes, they're legit. Logistics are ex-France.

User avatar
Mandrake
Posts: 8196
Joined: 10 Apr 2005, 17:23
x 328

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Thats good to know addo.

BTW Jim, I just noticed AFTER ordering that the plug leads I've ordered say they are resistive. Any thoughts on that ? As I said, the leads in there now definitely measure as resistive leads around 4-6k (with two leads having intermittent breaks) so it must be that there is more than one version of the leads... does anyone know the resistance of the actual plugs ?

The plugs I fitted from GSF were Bosch FR7DC+ which at the time I ordered were the only ones they listed for my car, however now when I check again on their website it says in the comments section that the plugs are recommended for CNG/LPG. Wait, what ?? I don't remember seeing that when ordering... :roll: They also now list NGK BKR6EK as available, which weren't listed a few weeks ago.

So my question is, are the plugs that I have suitable for petrol, or have I bought the wrong ones ? :evil: I'm assuming the difference could be the plug temperature.

Never seems to be simple to get the right parts for a Citroen does it, especially from GSF...(who also sold me the wrong handbrake cable) :roll:

Edit: Just looked up the Bosch plugs I have from GSF and they are NOT resistive plugs, while the NGK type listed by GSF are resistive. The plot thickens. :?

Bosch: http://www.gsparkplug.com/shop/bosch-fr7dcplus8.html" onclick="window.open(this.href);return false;

NGK: http://www.gsparkplug.com/shop/ngk-bkr6ek.html" onclick="window.open(this.href);return false;

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

Simon, plugs are a nightmare :twisted:

First thing is, the Bosch FR7L series ARE resistor plugs. You know how I know? I have a set of FR7LDC here brand new and they measure 4K each!!!! I measured them. Sorry but the website is wrong...

No matter even if you use them with resistive leads. An extra 4K on top will make no odds at all... The NGK BKR6EK and FR7LDC are direct equivalents. Both have twin electrodes. The FR7DC is a single electrode job. The + part means the plugs have precious metal electrodes.

You only really need the fancy ones with precious metal tips if you are running LPG so I'd say a set of the FR7DC+ are more than perfect for you. They have Yttrium electrodes. In my experience, none of the PSA engines are exceedingly fussy of plugs unless running alternative fuels. I have a set of BKR6EIK in my XM and they are Iridium tipped jobs with very tiny needle-point electrodes and they do seem to make a small difference when running on LPG.

Resealing a cambox in an ES9 engine is FUN! basically, you need to have the cambelt off and cams out and then very carefully reseal using the right sealant. They have no gaskets at all, just a shallow channel for the bead of sealant. Until it gets bad enough to cause enough oil loss to cause smoke I'd not worry overtly but do have the manifold off and check the plug well for oil at regular intervals.

If you are careful and don't use any gasket sealant on it the inlet manifold gasket can be re-used a couple of times at least..

That's a good deal on the leads :-D

User avatar
Mandrake
Posts: 8196
Joined: 10 Apr 2005, 17:23
x 328

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Hi Jim,

If it helps at all, the same website says that the FR7DC is a resistive plug with normal electrodes, while the FR7DC+ is not a resistive plug and has yttrium electrodes. So unless you have a pair of FR7DC+ on hand to measure I'm still inclined to believe that mine are not resistive plugs.

I could easily pull one out when I do the leads and measure it, although I'm worried about how well it will seal a second time after the crush washer on the plug has already been used once... one other thought as well, how can I tell if the plugs are sealing properly and what would the symptoms be if they were not ? The face where the plugs screw down onto is a bit dirty, I did my best to clean it with some rag on the end of a socket extension, but its really hard to get at to clean thoroughly, so I'm concerned there could be some grit stoping one or more plugs sealing properly...

Since the work the other day the idle is not as steady. When cold the idle is perfect, as the car warms up and the idle speed drops it starts to become a bit erratic, and it wasn't like this before. Despite the poor running the hot idle was perfectly steady before. :? Of course it might just be that the faulty plug leads are even more faulty after moving them around during the work, I won't know until those are changed. It's also possible that fixing the inlet manifold leak has change the idle characteristic, but why for the worse I don't know.

The cam box sounds like a job for when I'm living somewhere with a garage! :( Obviously it would be crazy not to do the cam belt and water pump at the same time and that's not a job to be tackled lightly, nor tackled in a car park...so it will just have to wait. Fortunately I don't do a high mileage as the car is not a long distance commuting workhorse...

Some more oil has arrived for a second ATF change, just waiting on the manifold gasket and spark plug leads now.

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

I didn't look that far into the plug types Simon, I must confess. The ones I measured here were in fact FR7LDC+ Yttrium tipped jobs so I do tend to feel that any Bosch plug with an R in its name is resistive but no matter... As I sad before, the extra bit of R is not going to be a problem...

When doing the timing belt, which actually is easier than generally believed, along with the water pump it's a nice idea to swap (if not already done) to a C5 type automatic eccentric tensioner rather than the rather complex dynamic tensioner the engine was fitted with originally; those must be set with a SEEM gauge whereas the C5 eccentric is set by adjusting it until two arrows line up.

The downside is that a full cam belt kit is bloody expensive but I know Chris570 found a good source of them at a not totally piggy bank busting price...

Looking forward to seeing what improvement a new set of leads make...

User avatar
Mandrake
Posts: 8196
Joined: 10 Apr 2005, 17:23
x 328

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Me too.

Just thinking outside the box here regarding the gearbox Jim, do you think there is any possibility that the erratic shifting behaviour I sometimes get with the gearbox could be due to poor electrical connections between the ECU and the gearbox ? Are the plugs on the wiring loom somewhat accessible such that I could dose the connectors with some contact cleaner ?

What if one of the electrovalves like the one that regulates the rail pressure or the one that operates the torque converter lockup is not getting a good reliable electrical feed ? I imagine that could cause havoc (and potentially clutch damage) and not necessarily log a fault if its not a complete open or short...

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

It's worth a shot Simon, the connector (called a KOSTAL) is right on top of the 'box and acceessible'ish. It's a meaty old thing and has a quarter-turn ring and handle sort of thing on it to release it... I'd try to get some electronic contact cleaner in there and blow it dry with an airline. There's often ATF hanging around the KOSTAL connector as it's not particularly well sealed into the casting...

I'd have a look at the ECU connector too. The autobox ECU hides under the battery tray and it's really not a good place for it to be. The one in my original V6 looked like a relic from the lost city of Atlantis but was OK and cleaned up well.

User avatar
Mandrake
Posts: 8196
Joined: 10 Apr 2005, 17:23
x 328

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Oh dear oh dear.

Just back from driving into Glasgow and back (20 miles, most of it motorway) and not wanting to sound like the boy that keeps crying wolf, but I think the torque converter lockup clutch (at minimum) is about to spit the dummy in a big way. :(

Cruising at 60mph in 4th even a moderate increase in throttle was lifting the revs at least 500 rpm with no increase in speed, the sudden increase in revs made it seem like it was changing down a gear but its clearly the torque converter lockup (or some other clutch) letting go as if I manually change it down a gear the revs go up 1000rpm instead of 500.

With variations in throttle I could feel it constantly gripping then slipping, it seemed like anything other than moderate throttle the torque converter was in full open slip mode even in 4th, where normally it will try to stay locked up at those speeds in that gear. :(

At slower around city speeds it was making some awful noises (accompanied by intermittent slipping) along with the usual groaning noise...either one or more clutches is slipping under load due to the clutch being damaged, or the rail pressure is too low allowing the clutches to slip. (Sadly there is no way to measure the rail pressure with the Lexia like there is on the AL4) What it was doing today is NOT engine related as far as I can see.

I fear this gearbox's days are numbered and even another change of oil is unlikely to rescue it. Sigh. :cry:

Why oh why couldn't Citroen have provided a manual gearbox option on the V6....(yes I know there are some manual V6 Activas, but they're like hens teeth) I think if it does die then it's no more automatics for me, the constant threat of failure after a certain age or mileage is just too much of a burden especially when its your only car. :?

User avatar
CitroJim
A very naughty boy
Posts: 42145
Joined: 30 Apr 2005, 23:33
x 1237

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

No worries Simon, just pop the 'box out, send it down to me and I'll rebuild it for you...

Don't send me the torque converter, send that direct to Mackie's as they're just down the road from you in Paisley...

In fact Mackie's will do the whole job for you.

Sadly yes, from how you describe it the 'box is not a totally happy bunny. This other noise? What did it sound like?