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

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

Post by Mandrake »

Has anyone else noticed that only a day or two after being seriously threatened with being sold (yes I was serious) the very next thing that I checked, by pure chance, turned out to be the problem ? (Or at least seems that way so far)

Does anyone think that car knew it was for the chop and decided to relent ? :-D I guess the moral of the story is NEVER assume that because you have replaced something a few months earlier with a brand new part, that it can't possibly be the cause of the problem you're seeing... if you think that way there are some problems that you will never find. Every symptom needs to be treated on its merits without assuming replaced parts are working 100%, certainly for parts like coils which can often become "iffy" rather than completely fail... #-o

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

Post by lexi »

It's strange that the ES9J4S is supposed to be more economical than the ES9J4 (mainly due to the VVT if I recall?), so whilst I'm thrashing Simon's mpg, I'm still a fair way off Jim's economy figures.
Weight maybe?

Vel is big mind, but I had 36mpg on a 162mile run last week on country roads. I was driving like a guy who had an allotment and played bowls though :lol:

Caravans were passing me and giving the finger........just the caravan with no towcar :shock: :lol: :lol:

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Ben82
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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Ben82 »

lexi wrote:
It's strange that the ES9J4S is supposed to be more economical than the ES9J4 (mainly due to the VVT if I recall?), so whilst I'm thrashing Simon's mpg, I'm still a fair way off Jim's economy figures.
Weight maybe?
Just had a look on parkers at the stats, there's about 30kg between the Xantia and the C5. The quoted mpg is 24 and 27 respectively. Going by that, Jim should be able to hit 40mpg in a C5 v6 :D

I had a look to see if there were any Vels for sale over here (out of curiousity as I've never seen one (here or in the uk)) but there were none. Also looking on one of the parts suppliers sites, they don't even list the Vel, so at a guess it was never released over here.

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Chris570
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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Chris570 »

Mandrake wrote:
CitroJim wrote:It was generally rough running Simon. Stumbling on pickup, misfires and popping in the exhaust on occasions...
Apart from popping in the exhaust, the same symptoms I was seeing, although I suspect mine was a lot worse.
If only you can try moderating your driving you will find a well-sorted V6 can be very economical. I see around 35mpg out of mine on my regular forays into Somerset and I reckon the XM has the edge. Maybe because it's more aerodynamic or how I drive... The XM imposes a different sort of driving style; a laid-back gentle one. the most pointless part of my XM is the sport switch :wink: It's never used.

Those that know me do know my driving style is quite moderate.
Don't worry Jim, I'm no Xac. :twisted: My driving is really quite moderate and smooth most of the time but I like to open it up sometimes, where its safe of course. I like to have the power on tap and have the responsive throttle even if I'm not using it all the time.
I assure you the V6 Jim is talking about was almost un-driveable, it was that bad. The popping was unburnt fuel in the exhaust..... I have a theory that the engine was also cutting out when slowing down to junctions causing hydraulic pressure to drop in the autobox, showing a load of stupid symptoms...

As a side note i get 33mpg from my XM ES9 with mixed driving (including the odd booting it) and i've got a sh*gged O2 sensor.

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Chris570
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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Chris570 »

CitroJim wrote:
Mandrake wrote:I like to have the power on tap and have the responsive throttle even if I'm not using it all the time.
That's precisely what I like about the V6 and find dangerously lacking in smaller offerings... Not that I use it often but a good reserve of power can be a great safety aid..

I also like the big brakes too...

Some small engined cars I feel positively unsafe in. One I don't is the Activa as despite only having a small engine it's not short on urge in all the right paces :-D
Let's get you some manly brakes on the Activa then ;)

While we're at it i'll 'adjust' your boost to a level with a hairy chest :P

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

Post by Mandrake »

Chris570 wrote: I assure you the V6 Jim is talking about was almost un-driveable, it was that bad. The popping was unburnt fuel in the exhaust.....
At times including the last week mine has been almost un-drivable as well. Enough to push me to the point of getting rid of it. It was making my old 125hp 2 litre Xantia look positively sprightly!
I have a theory that the engine was also cutting out when slowing down to junctions causing hydraulic pressure to drop in the autobox, showing a load of stupid symptoms...
Bear in mind that the deceleration cut-off will cut the injectors completely on the over-run, although only above 1400 rpm, and then will re-enable them if you get below 1100 rpm. It's also normal for the engine RPM to drop to about 1000 rpm at certain speeds with no throttle if the torque converter lock-up clutch is fully open as the torque converter only couples efficiently one way.

At least mine does that. I notice the steering becomes heavier if I'm drifting with no throttle in these conditions and the rpm has dropped to 1000. If the torque converter happens to be locked up when you release the throttle the engine RPM stays up as it would in a manual, so it all depends on whether the ECU has decided it should be locked or unlocked at the time.

What "stupid symptoms" were you seeing exactly ?
As a side note i get 33mpg from my XM ES9 with mixed driving (including the odd booting it) and i've got a sh*gged O2 sensor.
As I said I managed 32.8 on a trip and that was with plenty of booting it up hills and overtaking and a full load, as well as a bit of slow driving through small country towns... so they can certainly manage 33 ish on a trip. I'm curious to see what I'd get now on a proper trip especially with 99 fuel as I managed the 32.8 on 95 and around town it gets a lot better mpg on 99 than 95...

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

Post by CitroJim »

Mandrake wrote:Has anyone else noticed that only a day or two after being seriously threatened with being sold (yes I was serious) the very next thing that I checked, by pure chance, turned out to be the problem ? (Or at least seems that way so far)
I'm surprised you even needed to pose this question Simon. It's a well-known fact they know and respond to feelings. They can sulk too. My V6 Xantia is a terrible sulker and will throw up something if she feels neglected...

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

Post by Mandrake »

Yep, this car is a sulker too Jim :lol:

Went for a short drive today, overall far better and much more power than its had lately but not as good as yesterday, its hesitating a bit again at lower rpm, the pickup is sometimes not as quick as it should be but then after a slight delay it will usually pull strongly at low rpm.

Perhaps the old coil pack while better is still not 100% ? After all I did replace it in the first place looking for a misfire...or do I still have a genuine low fuel delivery problem as well with a blocked pump strainer ? Or perhaps still intermittent knock sensor activity ? Hard to tell but its still not 100% right, and there is nothing to say that there was only one problem!

A possible sign that there were multiple problems is that the idle is still perfectly smooth and miss free today despite the hesitation when pulling at low rpm.

I just realised that the coil pack is well under a year old so if I can remember where I got it from (!) I might be able to get it replaced under warranty. I've nothing to lose trying as the faulty new one is no good to me now.

Northern_Mike

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

Post by Northern_Mike »

CitroJim wrote:
Mandrake wrote:Has anyone else noticed that only a day or two after being seriously threatened with being sold (yes I was serious) the very next thing that I checked, by pure chance, turned out to be the problem ? (Or at least seems that way so far)
I'm surprised you even needed to pose this question Simon. It's a well-known fact they know and respond to feelings. They can sulk too. My V6 Xantia is a terrible sulker and will throw up something if she feels neglected...
It's not as bad as it used to be. Mine used to destroy themselves when they found out I was about to sell them. The Volvo 360 that ate it's diff on the way to be traded in, the Orion 1.6 that threw a leg out the day before I sold it, the Astra GTE that dropped a valve 2 days before it was being traded in.. the list goes on and on!

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

Post by Mandrake »

Contacted the seller of the now faulty coil pack on eBay about a possible replacement but I don't hold out much hope as its a parts clearance house who probably don't have any more, especially at the £70 I paid. The only other ones on eBay at the moment are £140 for an intermotor branded type and £220 for one of an undisclosed brand! :shock: Probably all I can hope for is a refund but it won't even come near the cost of replacing it. :(

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Post by addo »

Was it showing unreliable dwell times per plug pair?

My engine problems were in two batches. One batch came with the blocked exhaust, the other with a faulty positive terminal.

The faulty terminal was pre-Lexia; I swapped countless items at great cost with name brand new ones. Ultimately it was fixed for about $60 with new starter cable (heavy gauge and slightly longer) and a new brass battery clamp pair at the same time.

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Mandrake
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Re:

Post by Mandrake »

addo wrote:Was it showing unreliable dwell times per plug pair?
Do you mean were the three different coils showing significantly different charge times ? Or do you mean were the individual charge times fluctuating a lot from moment to moment ?

If the former, a couple of pages back in the thread I posted the ignition coil charge times at idle for the new now removed coil pack:

http://www.frenchcarforum.co.uk/forum/v ... &start=930" onclick="window.open(this.href);return false;

Charge time 4.09ms

Coil 1/5 +0.11ms
Coil 2/6 +0.06ms
Coil 3/4 +0.19ms

If you mean are they fluctuating a lot, its hard to tell when I can't graph the figures but I recall that the individual coil figures did seem to be fluctuating significantly although I don't recall which ones and by how much.

I'm still not sure that I understand what the figures are showing. Charge time I understand - its how long it takes the current ramp to reach the peak current each time the coil is charged, in this case 4.09ms. Fair enough.

But I don't understand what the individual coil readings represent. The heading in the Lexia is "Charge time reg. :" whatever that means ? No documentation of course... does that mean that you add the base charge time (4.09ms) to the individual figures, say 0.11ms of the first coil to get the actual charge time of that coil ? So the charge time of coil 1/5 is actually 4.20ms then ? Therefore the individual figures are just showing you the relative difference in charge time of each coil...
My engine problems were in two batches. One batch came with the blocked exhaust, the other with a faulty positive terminal.

The faulty terminal was pre-Lexia; I swapped countless items at great cost with name brand new ones. Ultimately it was fixed for about $60 with new starter cable (heavy gauge and slightly longer) and a new brass battery clamp pair at the same time.
What symptoms were you getting from a faulty battery terminal ?

I've got a new negative terminal but haven't fitted it yet. These halfords clamps aren't that great really. I originally went and got this one:

http://www.halfords.com/webapp/wcs/stor ... yId_255205" onclick="window.open(this.href);return false;

Which they say is a "four way" terminal, whatever they mean by that. Turns out that the hole for the cables which you can't see in the picture is far too big for the two cables I need to insert, even if I fold them back double. :?

So I took it back to get this one which they claim is a "two way" terminal, thinking that the hole must be smaller in diameter to suit inserting two cables:

http://www.halfords.com/webapp/wcs/stor ... yId_255205" onclick="window.open(this.href);return false;

Well it turns out that the hole in the main clamp section is slightly smaller but only just, and its still going to require folding the two cables back at least double maybe even triple to clamp properly, which is why I haven't done it yet while I explore other options. :? Even the guy in halfords couldn't tell me what 2 way and 4 way meant....it didn't seem to have any correlation with anything on the clamp - both require at least 4 thick cables to get a decent bite on the clamp, and while my positive terminal has 4 cables the negative only has two, and not very large at that.

Still trying to decide how best to fix the battery clamp.

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

Post by Mandrake »

Ok guys, intermitent power loss and hesitation is beginning to creep back in again, including a slight miss at idle... :roll: whats going on ?

Original coil pack not 100% either ?

Intermittent wiring somewhere in the engine loom ?

Voltage drop across my spade connector which shouldn't be in series with the ECU feed ? Voltage drop across my negative clamp even though it seems tight ?

Something unrelated like fuel delivery, eg coincidence ? Fuel delivery wouldn't explain a miss when idling though since fuel demands are low at idle, but could affect wide throttle performance.

Swapping the coil pack over made a massive difference, but maddeningly it isn't lasting with symptoms beginning to creep back in after only two days!! :?

Trying to think of the best way to get some direction on where to look. Perhaps I need to check the earth returns for the ECU and battery. Does anyone know where the earth connection on the ECU connector goes to ? Does it go to a bolt somewhere on the engine or does it run directly to the earth multi-plate beside the battery ?

How many earthing points are there on the engine and where are they ? Earthing is something I haven't checked at all, so I really need to check all the earth returns are good, particularly the ones the ECU and sensors rely on.

Northern_Mike

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

Post by Northern_Mike »

Mandrake wrote:
Intermittent wiring somewhere
This one. It can't really be much else, can it?

I do hope you've repaired your battery clamps.

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Ben82
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Xantia V6 broken exhaust (update: and rough low rpm running)

Post by Ben82 »

Simon, have you checked SEDRE? Pretty sure that'll give you a good idea where the Ecu is grounded (Using The "Installation" diagram). Pretty sure one of the sections in SEDRE is "general earthing points" too so might give you an idea of where the ones that are used on the engine (of course the engine is one big hunk of metal so really any bolt on it turns into an earthing point but you're really only interested in the ones used :) )

Pretty sure your favourite youtuber has a video on ground noise testing using a scope with the differences between a good and bad ground :)