Simon's new Xantia V6 and Leaf blog

[Mandrake]

I cleaned the throttle plate area thoroughly yesterday. One of the symptoms before cleaning it was that holding the throttle open just a fraction was causing it to try to stall.

Despite idling perfectly with the throttle closed (now that the ICV is working) holding the throttle open just a fraction would cause the revs to drop down to a near stall, surge back up to above idle, drop down to a near stall etc in an endless cycle that occurred every 2-3 seconds. Also there was an annoying stumble/hesitation when accelerating from the lights even with a relatively light throttle - just like the old car...

Both these symptoms only appeared after fixing the ICV, since before that it was idling too high for a stumble to occur and the computer had no idle speed control to be able to cause the idle speed to cycle up and down.

I'm pleased to report that cleaning the throttle plate has cured both symptoms. No more hesitation on take off and no more trying to stall or engine speed trying to cycle up and down by holding the throttle slightly open. I did have to reset the ECU for it to fully adapt to the clean throttle plate though.

The interesting thing was the throttle plate wasn't especially dirty. It was visibly black and dirty around the edge, but I've certainly seen worse... It doesn't take much to upset the delicate balance between idle control and throttle progression!

[CitroJim]

That's interesting Simon. I should have done Steve's when we had the inlet manifold off and will certainly do mine when I have mine off to do the plugs...

[Mandrake]

You don't need to take the manifold out to do it Jim. Just remove the air filter box and rubber sock to reveal the throttle plate.

Its only the edge of the throttle plate and the throttle body immediately around where the throttle plate rests when closed that matters. There is supposed to be a calibrated air leak around the edge of the closed throttle plate - oily carbon residue works like a gasket and blocks this deliberate leakage.

This means when you start to open the throttle slightly air flow doesn't immediately increase until the plate tilts far enough to move past the muck, hence causing a dead zone. Also it causes the ICV to have to open more than normal to reach idle speed. When its clean even the slightest rotation of the throttle plate causes a progressive increase in air flow. You can feel a more progressive, immediate response to very small throttle openings when accelerating from stationary when it's clean.

A spray can of carb cleaner, a soft cloth and a few minutes of elbow grease is all it needs. I found it easy to just hold the throttle plate wide open by pulling the accelerator cable in one hand - you need to clean right up around just behind the lip in the throttle body where the throttle plate rests as well as the bit you can see.

[Mandrake]

Not much to report really - the car is running nicely, although it hasn't had a huge amount of use lately. A few observations though.

I am considering giving the gearbox a hot flush after all when I can afford it, after more urgent things have been done. Most of the time the gearbox is smooth and nearly flawless, but not always. Sometimes the changes are less than stellar and torque converter lockup a little abrupt... Then the following day its absolutely fine again.

No particular pattern I can see which makes me think that 1000 miles of hard use in a week after years of slumber may have caused some dormant dirt/debris in the gearbox to come loose and start trying to gum up the valve block, hence slightly intermittent operation. It does feel like a slightly sticky valve block.

Just because it's done a low 65k doesn't mean the oil isn't filthy and in need of flushing, it will be if its never had any oil changes - I'd have to go through the receipts again to be sure but when I scanned through them last time I did NOT see any mention of a gearbox oil change. I also haven't checked the gearbox oil level yet, but without flat level ground I can't easily do that at the moment.

If the oil is filthy it would take at least 3 changes to get it nearly clean - which costs nearly as much in oil costs alone as a professionally done hot flush, so I think my money is better spent by taking it into Mackie's in a couple of months time for a hot flush and be done with it...

After the initial lack of power when driving the car back home from Preston and a slightly intermittent power loss for the first week or so the engine seems to have settled down nicely now. It starts perfectly, idles at the correct speed now the ICV is clean and has lots of get up and go. It pulls willingly at 1200rpm in 3rd which couldn't be said about the last one!

Put it in sport mode and it winds up to 6000 rpm very nicely and is very responsive and aggressive. Its at least as good as the other one was before it started having its problems, probably better. Under power the engine is not as quiet as it was when I first got it - but that's because I believe the initial lack of power bringing the car home was woefully retarded timing. (Which was cured with a battery off reset) The retarded timing makes the engine very quiet and smooth like a kitten but kills the performance too.

Now that its consistently performing well it SOUNDS like a V6 too, with a kind of subdued roar under throttle instead of the meek little purr that it had at first... Its still not as noisy as the other one though, both engine roar and tappet and timing belt noise is far quieter than the old engine - drive it with a light throttle and the engine is almost silent.

The plug leads look old and tired and need replacing and with them so will the spark plugs, but I need to try to find a new spark plug lead guide somewhere as the old one is broken in half and they're now NFP...

There has been no use of coolant at all, so it looks like the coolant expansion chamber is ok...for now (it's already been replaced twice in its 65k according to receipts, as well as a new radiator!)

There are two odd engine related sounds that it has always had though that I can't pin down which maybe Richard or David will have an idea on when they see the car.

The first one is that when accelerating between certain rpm - I forget what exactly but I think its around 2000-3000 the engine note has a kind of "buzzing" to it. A bit like a bumble bee is the best way I can describe it. Above and below the buzzing goes away.

My first thought was it might be the broken windscreen scuttle which is literally broken in half in the middle, vibrating and buzzing at certain engine rpm - it certainly sounds like its coming from that area. But then I started to wonder if it could be the exhaust hole. There is a hole just in front of the rear back box that has got a lot worse in the time I've had it to the point that its obvious when the door is open - I wonder if an exhaust hole could cause a "buzzing" sound at certain rpm ?

Strange noise number two is a really odd one - sort of a whining noise from the engine bay, its difficult to pin down whether its road speed, engine speed, or throttle opening related. It appears when the throttle is open and goes away completely when closed. First thought of course would be a worn diff in the gearbox but I don't think so. It doesn't seem to be road speed related, and doesn't have a sudden on/off characteristic as you apply and remove the throttle. It comes and goes gradually as you adjust the throttle, and although the pitch changes slightly it only changes in response to throttle opening not engine speed.

It seems to occur within a certain rpm range, but it's quite a wide range - about 1500 to 2500 rpm or so, and only with the throttle open. Its loud enough to be quite obvious, although part of that is that the car and engine in general are so quiet that any remaining noises seem obvious. However the old car did not have this noise at all.

My gut feeling is that it is an induction noise of some sort as it does seem to be related to intake air flow. I thought maybe the stuck open ICV could have caused it but the noise remains after the ICV was fixed. I'm a bit stumped to be honest and hoping Richard or David might have an idea or at least be able to describe the noise better! As long as its not the gearbox I don't think its anything to worry about, but it does annoy me a bit.

Spheres are still waiting patiently - I think I'll be able to order them when I'm paid at the end of the month, although paying the upfront costs for moving house obviously take priority. I looked at that site that sells IFHS directly and for 8 spheres they want £200, (£25 each regardless of type) and I'm not sure how much postage there is on top of that, so it might be cheaper to just buy from AEP and pick them up over the counter...

Hopefully there will be a fine weekend next month for a visit to Richard to fit them and show off the new car however if the weather doesn't cooperate they might just have to wait until I have my own garage to work in some time in October!

[CitroJim]

Simon, if that's how much you write when there is not much to report then I dead the time you really have a lot to report

Noises I've no idea on but I do agree a fluid change on the 'box will not be a bad idea. Whether or not it needs one of these hot flushes is moot. I'd be tempted to get a sample out of the 'box and have a look.

Far more important I reckon is to do those spheres ASAP. The car was terribly hard when I saw it.

Has the cambelt been done? I ask as I'd be a bit cautious regularly taking it to 6K if it has not. I do it soon on a time-expired basis even if the mileage says it still has 20K or so to go.

Otherwise, absolutely delighted all is good

[xantos]

Glad to hear your car is working (almost) perfectly! If you wouldn't be such a perfectionist we could say perfectly without (almost)

Spheres are still waiting patiently - I think I'll be able to order them when I'm paid at the end of the month, although paying the upfront costs for moving house obviously take priority. I looked at that site that sells IFHS directly and for 8 spheres they want £200, (£25 each regardless of type) and I'm not sure how much postage there is on top of that, so it might be cheaper to just buy from AEP and pick them up over the counter...

Postage to UK for 8 spheres is £36.

[Mandrake]

Yes the spheres are top priority Jim, and are the next thing on the list. I'm going to try to slip them under the radar when I'm paid at the end of the month as I really want to do the whole lot at once, that's the spheres then sorted for about 3 years...

Xantos - if its another £36 on top of £200 that's definitely more expensive than AEP (whose office is a short driving distance for me) so I think I'll just go with AEP over the counter again.

Jim - as mentioned a long way back in the thread the timing belt was changed in late 2005, which means the belt is 9 years old but has only done about 20k. As the limit is 10 years or 72k (?) I think I should be ok to leave it until the spring, especially given the low mileage the belt has done. Realistically I have no chance of doing it before then anyway. All the belt rollers are nice and quiet too, (unlike the old car) which is not surprising as the roller bearings would only wear with mileage not age.

Don't worry, I don't make a habit of taking it to 6000! I rarely go over 4000 unless I'm really trying to overtake in a hurry...

One other thing I forgot to mention is that there is definitely a rattle in the steering at the front somewhere. I know you say you couldn't find any loose joints but when I hit certain types of corrugations or broken surfaces in the road when turning very slowly on a sharp lock there is an obvious rattle and a vibration on the steering wheel. Seems to be coming from the front right and is most noticeable on right lock.

There was a similar rattle on the old car too. If its not any of the outer joints I wonder if it could be an inner steering joint or even the steering rack not bolted down properly ? Might tie in with the steering vibration over 70mph too because I find any slack at all in steering joints magnifies wheel balance problems out of all proportion...

[RichardW]

Buzzing could be the exhaust - they do make some odd noises when they're going. If it's now audible, it's probably not that far away from letting go - they don't need that much rust before the flange clamp can't hold on any more - might be worth getting a bit of wire round it to stop if falling down on the rear sub cross brace (they may a terrible noise then ) - or is just on the pipe? I've still got part of the original exhaust flange lying about so we should be able to stitch it back together. That part is NFP, but was an amusing £217.61 when last available Think my 307 is developing a leak there somewhere too - there is a definite hissing on boost from the NSR - just about audible over the howling front wheel bearing. I shall miss it when I get it changed

On the steering noise / vibration, could be a track rod end - I had an odd noise like this on one of mine. Thought it was a wheel bearing as it would go away when the steering was just off centre. However, eventually found some play in the track rod end, and surmised that a slightly out of balance tyre was causing the TRE to oscillate and make a noise. Once new TRE was fitted noise went away. I found that there was no play in high suspension as the angle on the rod locked it up, but if you shook the wheel with it on the ground you could feel the play. Could also be the bottom ball joint - these are notorious for hiding small amounts of play when they are connected up - only way to confirm really is to split the joint and have a feel of it.

[myglaren]

I was just reading that some Skodas have a buzzer under the dash that operates when you accelerate to make it sound as though the engine is more powerful than it actually is

Perhaps someone modified your V6 with one

[Mandrake]

Buzzing could be the exhaust - they do make some odd noises when they're going.

After listening to it a bit more carefully the last few days I'm pretty sure now that it is in fact coming from the rear of the car and probably is the exhaust hole in front of the muffler.

If it's now audible, it's probably not that far away from letting go - they don't need that much rust before the flange clamp can't hold on any more - might be worth getting a bit of wire round it to stop if falling down on the rear sub cross brace (they may a terrible noise then ) - or is just on the pipe? I've still got part of the original exhaust flange lying about so we should be able to stitch it back together. That part is NFP, but was an amusing £217.61 when last available

I haven't had the car up on ramps since I bought it so I haven't been able to have a close look, but it appears to be only the pipe that is rusty - right at the bottom side of the bend in the pipe which is about an inch or two in front of the clamp to the rear muffler. I think the muffler itself and clamp flanges are ok. So two half sleeves welded over the rusty section of pipe is probably all it needs. The rusty section is only about 2" long.

The rest of what I can see of the exhaust system looks pristine for its age. Even the clamp on the rear of the cat that broke on the other car and triggered the broken exhaust thread looks fine and still has the original type of clamp.

Think my 307 is developing a leak there somewhere too - there is a definite hissing on boost from the NSR - just about audible over the howling front wheel bearing. I shall miss it when I get it changed

Ah, funny you mention the hissing - I've noticed a quite audible hissing as well, but only under wide throttle when you get above about 4500rpm - then it starts to hiss like a tyre being let down, also from the rear. I guess that is also the same leak when there is sufficient flow and pressure at high engine speeds and throttle! The old car had the same hissing noise and also had a leak nearby, although on that car it was the clamp itself that wasn't a perfect seal.

On the steering noise / vibration, could be a track rod end - I had an odd noise like this on one of mine. Thought it was a wheel bearing as it would go away when the steering was just off centre. However, eventually found some play in the track rod end, and surmised that a slightly out of balance tyre was causing the TRE to oscillate and make a noise. Once new TRE was fitted noise went away. I found that there was no play in high suspension as the angle on the rod locked it up, but if you shook the wheel with it on the ground you could feel the play.

Yep I had exactly the same problem on the old car - a wheel vibration that came and went intermittently around 75mph and wouldn't go away even when the wheels were balanced - it turned out to be about 1mm of slack in the right hand outer track rod end. I replaced both outer track rod ends and re-adjusted the wheel alignment and the vibration went away completely.

I came to the same conclusion as you - that a slight, normally inconsequential wheel imbalance (they're never perfectly balanced) was enough to set up an oscillation in the steering angle of the hub with the slack track rod joint - basically the wheel "wobbles" side to side on the slack in the steering on that side, which is why there is so much vibration passed through to the steering wheel.

Could also be the bottom ball joint - these are notorious for hiding small amounts of play when they are connected up - only way to confirm really is to split the joint and have a feel of it.

Funnily enough I still have a pair of brand new Lemforder (I think ?) bottom ball joints that were bought for the old car when I was chasing said vibration - which were never fitted as the track rod ends solved the vibration.

I'll try replacing the outer track rod ends first and see if that helps, if not I may need to do the bottom ball joints or inner track rod joints. Finding this vibration isn't urgent though, it's something I'll do at my leisure in my new garage when I have the time.

[Mandrake]

Jim will be pleased to know that I ordered a full set of eight spheres this morning.

I ended up ordering them online from AEP as it was significantly cheaper than the other options for IFHS spheres... £190 all up including VAT and free delivery.

I have all next week off (and the weather report looks fantastic ) and was hoping to swap them over early next week so I was a bit disappointed to get an email half an hour later informing me that only 3 of the 8 spheres were in stock and the rest would be 5-7 working days...

Predictably the spheres they did have in stock were the anti-sink and front and rear Hydractive regulators - the ones that often get overlooked.

If I'm lucky they might arrive next Friday but I'm not holding my breath.

Other than that not much to report, except when starting this morning there was a momentary hesitation before the starter clicked in which I recognised immediately as marginal voltage to the starter solenoid - probably due to the cold weather this morning.

As far as I know this car hasn't had the starter relay modification done yet, and aside from this morning it has never shown any starting symptoms, but with cold winter weather on the way in a few months I think I'll do the relay mod preventatively - perhaps even next week while I'm waiting for my spheres...

[CitroJim]

That's good Simon. The ride will be very much improved I'm sure It should make your car just about perfect!

I'd definitely do the starter mod, it's excellent insurance against trouble when you most need a starter.

Thinking on, I'm not sue my V6 has been done yet I will check and if need be do this weekend whilst I'm doing the cambelt and HP pump...

[KP]

Why not get them to send the ones they have in stock and get them fitted while you wait Simon? Also they are some of the harder ones to do and while your there soaking the joints of the others with some penetrating fluid would help when you get back to them?!

[Chris570]

Why not get them to send the ones they have in stock and get them fitted while you wait Simon? Also they are some of the harder ones to do and while your there soaking the joints of the others with some penetrating fluid would help when you get back to them?!

What he said

[Hell Razor5543]

^^^ What they said ^^^. Just think yourself lucky it isn't an Activa, with the last two spheres that (apparently) cold weld themselves into place!