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 »

Thanks addo, that does look like just the ticket for making up an exhaust back pressure adaptor...

Meanwhile I've got some cheap in-line spark testers on their way... the idea being to monitor the HT output of all three coils at once visually during a cold start to see whether what sounds like misfiring is in fact in intermittent loss of spark on one or more coils or whether it's something else. (It was doing it again today when started for the first time in a few days, particularly noticeable around 1000-1200 rpm, and it persisted for the minute or so before I drove off) I'll try to get my scope onto the drive signals to the coils as well. Since they're only low voltage I can probably just spike them with a very fine pin to get a connection without messing around trying to make a breakout harness.

The result I get from those tests will then determine where I focus next...

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DickieG
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Post by DickieG »

addo wrote:A faulty lifter often manifests on a compression test, as noticeably slower pressure climb than "good" lifter cylinders. It's the sort of additional detail that's taught - you watch the needle's behaviour as it climbs on each pot.
If the engine only had two or maybe three valves per cylinder that might apply but with four I just can't see it as only two of the four would be necessary to achieve a decent figure/pressure climb on a compression test. After all many 4 valve per cylinder engines shut off two valves at low rpm and/or have VVT in some form or another to increase combustion chamber swirl/turbulance.

The only sure way of eliminating this potential fault for sure is to lift off the cam covers and use feeler gauges.

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

Post by Mandrake »

Planning to go out and do various tests on the car today, can anyone describe where the two pipes just below the main throttle body intake go to and what their exact purposes are ?
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The left hand one looks like a crank case breather but where does the other end terminate ?

The right hand one heads off towards the battery...could they in any way cause poor running if they had leaks ?

Do they just go into the throttle body on the vacuum side of the butterfly or is there more going on in the housing ?

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Post by addo »

A slightly oversized hose clamp says the amateurs have gone before you. It will probably be the carbon canister purge line.

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Mandrake
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Post by Mandrake »

addo wrote:A slightly oversized hose clamp says the amateurs have gone before you.
:lol:

Is there originally a crimped clamp there or was it push fit ? The rubber is too hard now for a push fit seal...
It will probably be the carbon canister purge line.
Which does what exactly ? Sorry, my knowledge of 21st Century anti pollution systems is pretty limited...

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Post by addo »

That hose normally has a "Clic" clamp; the removal and refitting thereof separates men from boys (or at least, those who have the tool, from those who don't).

Behind your NSF blinker there's a black tubular canister. It will have a vapour line with brown (maroon) solenoid entering your engine bay somewhere near the back of the nearside headlamp. From the solenoid, the line ("purge") passes to the vacuum side of your throttle flap.

Disconnecting the solenoid plug will make no measurable difference to performance but put the K light constantly on. Disconnecting the purge infeed will cause a sizeable vac leak that sucks power at lower revs and may cause a high, unstable idle. Flat stick it won't make much difference.

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

Post by Mandrake »

Thanks for the info.

It looks like my afternoon of tinkering on the car has been brought to a screaming halt. Dressed in overalls with plenty of layers underneath and hands full of tools I arrived at the car to find a half flat front right tire with the head of a wood screw poking out of the middle of the tread. :evil: So my afternoon will now consist of finding somewhere to fix a puncture that won't screw up the balancing of my centre-less rims... oh joy. :roll:

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

Post by Mandrake »

Well that's that hopefully sorted.

I went to two different places, as soon as I mentioned centre-less rims they both turned me away saying they couldn't balance them, I didn't want to drive far as my spare wheel is quite dodgy, so I ended up going to the local Citroen service agent just down the road from me on the theory that they at least should be able to balance Citroen rims! I was quoted £15 for puncture repair but inevitably the phone call came to say "can't repair as its too close to the sidewall"... :roll: They did have a point, the wood screw was embedded in the outer most major channel on the tread...

So they got a new tire up (a matching Michelin Energy) the next day all fitted and balanced, I'm now just waiting for a chance to swap it back on and check to see that it is actually balanced properly at 70mph...(after my previous hassles with getting centre-less wheels balanced I'm paranoid)

Always a bit gutting when a 6 month old tire with less than 3000 miles on it is written off but them's the breaks. :roll: At least the wear mismatch between the old and new one will be minimal once the new one beds in.

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

Post by myglaren »

I bought Vredestein tyres from ATS a while back, as they seemed to be the only ones capable of balancing the wheels.
They did an excellent job at a reasonable price and the tyres were 'insured' in case of such a puncture.
They would come to the car and do a roadside repair where possible anywhere in the country.
If the tyre was irreparable then it was replaced with a few % of the cost charged according to the amount of wear.

I have no idea if they still do that but it seemed a decent deal as the tyres cost the same as their competitors.

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Post by addo »

After tyre monkeys trying a similar pitch on me twice, I bought one of the old school DIY patching kits with the sticky rubber "cord" and large needle for insertion. Been good value.

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

Post by Xantidote »

Mandrake wrote:Always a bit gutting when a 6 month old tire with less than 3000 miles on it is written off but them's the breaks.
Yes, gutting. I picked up a screw in a nearly new tyre on the front a couple of years back.

I'm of the school that likes the best tread tyres on the front. However, it did occur to me that as the rear wheels generally follow the front, there is an added benefit in actually having the better treads on the rear, so that when one picks up a screw, it's likely to be the more worn front tyres that pick the screw up, so protecting the better rear tyres :-D

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

Post by citronut »

of you can keep the old tyre till you find an independent tyre shop they will be able to fit a mushroom patch as Adam says, they are allowed to do this anywhere on the tread face,

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

Post by Mandrake »

citronut wrote:of you can keep the old tyre till you find an independent tyre shop they will be able to fit a mushroom patch as Adam says, they are allowed to do this anywhere on the tread face,
Too late, the old tire is gone...I should have asked to keep it but didn't think about it, and didn't get to speak to the mechanics anyway.

I would have taken it for a second opinion on the repair but my spare tire turned out to have a huge crack on the sidewall (see below) so I wasn't happy driving any great distance on it unnecessarily nor driving much above 30mph...nowhere else within short driving distance would touch the centre-less rims so I didn't have a lot of options.

Does anyone agree the crack below is unsatisfactory even for a spare tire or am I just being paranoid ? The tire seems to be ok in other regards although the rubber is probably fairly old as most spare tires are...
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Mandrake
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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Time for a quick rant.

Got a chance to take the car for a 75mph drive to check the wheel balance (imbalance is always worst at 75mph on this car) and the new tire is not properly balanced. :evil: It's not horribly wrong like it was when the previous outfit fitted the two new tires last August and had 150g of balance weights per rim taking 3 tries to get it right (saga documented in another thread...) but it is definitely not balanced satisfactorily, not even close, I can feel it on the steering wheel as well as through the floor.

I know for a fact that all four wheels were perfectly balanced before the puncture so it won't be any of the other wheels. Considering that I took it to them specifically because most places can't balance the centre-less rims and I assumed Citroen could, annoyed is an understatement...is it too much to expect wheel balance to be done right first time ?

Looking at the receipt there is only £10 worth of labour and no mention of wheel balancing, and I don't see any new balance weights fitted or any sign of existing ones being removed or moved.

So either (a) they didn't even check the balance, or (b) checked it quickly with the existing weights, thought "close enough" and went on to the next job instead of taking the time to get the balance right.

Given that I didn't specifically ask for the wheel to be balanced (bearing in mind I only took it in for a puncture repair originally) where do I stand exactly ? Correct me if I'm wrong, but isn't it totally unacceptable to fit a new tire to a rim without at least checking the balance ? In other words, the fact that I didn't specifically ask for it to be balanced is no excuse if they turn around and say I didn't ask for it or pay for it ? A new tire being balanced when fitted should be universally implicit ?

Maybe its a genuine mistake, but I'm bracing myself for the phone call tomorrow to get the problem rectified and hope I don't run into any more problems, other than the waste of more of my time and petrol...

This folks, is why I do as much of my own car maintenance and repairs as possible...although I'm sure I'm preaching to the choir here. :lol: Nothing ever seems to be straightforward with this car... :roll:

Northern_Mike

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

Post by Northern_Mike »

Mandrake wrote:
So either (a) they didn't even check the balance, or (b) checked it quickly with the existing weights, thought "close enough" and went on to the next job instead of taking the time to get the balance right.

Given that I didn't specifically ask for the wheel to be balanced (bearing in mind I only took it in for a puncture repair originally) where do I stand exactly ? Correct me if I'm wrong, but isn't it totally unacceptable to fit a new tire to a rim without at least checking the balance ?
In my view, yes, it is totally unacceptable. Take it back and demand they rebalance it. I have done this in the past when they've failed to balance wheels correctly.