Simon's new Xantia V6 and Leaf blog

[CitroJim]

Excellent news Simon

Detached cold air intake to the bottom of the airbox?

[Mandrake]

Excellent news Simon

Detached cold air intake to the bottom of the airbox?

Nope, haven't even had the air box out yet believe it or not...

It was the map sensor I believe, or possibly the spark plug leads, but pretty sure its the map sensor. I had checked it on the Lexia and it seemed to read as expected, but was talking to David about a problem with the map sensor on his Activa causing similar but less obvious issues so I thought why not swap it as I have a genuine spare and its 2 minutes work - the only other thing I did is wiggle the spark plug leads near the back of the manifold as the lead guide is broken at one end and not bolted down at the other and the leads look a bit shabby, but I don't think it was that to be honest.

I immediately noticed a big improvement in power and throttle response but it still wasn't what I thought it should be.

My test is to put the gearbox and suspension in sport mode, speed up to about 3000 rpm in 2nd gear (about 30mph) hold it there for a few seconds to let the torque converter lock up then floor it - if everything is good there should be an instant response that pushes you back hard in your seat as if it was a manual gearbox.

Before I swapped the map sensor there was half a second or more delay and the engine sounded quiet and meek when the power did arrive. The power increased after changing the map sensor but the throttle was still a bit laggy and the engine was still unusually quiet.

So I then did the infamous battery off (for 10 minutes) ECU reset and BAM!! It was like I had got into a different car, it was nothing like the car I drove 180 miles home...

Doing the same 3000 rpm test as above it responds instantly, pushes you hard back into the seat and to put it bluntly goes like stink. Better than the other one now even at high rpm. The engine makes more of a quiet "roar" now rather than purring, but it is still very quiet compared to the other car.

My theory is that a slightly iffy or sluggish map sensor was causing it to run lean when you put your foot down, knock and the timing got wound back just like I was seeing with the old one - except the cause was different. If the engine is unusually quiet and smooth, ("meek" sounding, rather than sounding like a V6) and has throttle lag then you can bet dollars to donuts that the ECU is knocking the timing back for some reason...

Oh, and the torque spike just above 4000 rpm is gone as soon as I reset the ECU - there is smooth power delivery through that range now. I believe the spike occurs because the timing only gets retarded BELOW 4000 rpm thus the sudden increase in power above 4000 rpm is only the power that should be there in the first place - the power only went missing below 4000rpm...

So a sudden jump in power and increase in engine noise every time you pass a specific rpm in the 3500-4000 rpm range is also a clue that the timing is being retarded.

Now we just have to wait and see whether the fix is permanent I'm going to put v-power in when I fill it up too to see if that helps, but at the moment its running better on 95 than the old one on 99...

[CitroJim]

Interesting on the MAP sensor Simon...

I'd still be doing a full service including plugs as soon as you can though...

What were you doing to the rear brakes?

[CitroJim]

Where's the map sensor located?

On the back of the inlet manifold Mike. It has a grey three-way connector attached...

[Mandrake]

Easy enough to replace then?

What should i be looking for if i get a lexia on her?

Mike I didn't see anything untoward on the Lexia regarding the MAP sensor. Unless it completely fails you wouldn't notice anything on the Lexia.

Why, are you noticing throttle lag and lack of vim and zest ?

[Mandrake]

Shoot me down if I'm wrong here Simon but what I think you mean is it's fundamentally a good car and just needs a few more bits doing to make it an outstanding one.

I think as you've written it you're thinking out loud (or typing) and it's not really a criticism of the car as such.

Yeah I'm not complaining really, just documenting what I've found. There is a lot that needed doing but I've done quite a bit of it already today and it's starting to feel like "my" car now.

[Trainman]

it's starting to feel like "my" car now.

You have no idea how happy I am to hear you say that

[Mandrake]

Interesting on the MAP sensor Simon...

I'd still be doing a full service including plugs as soon as you can though...

There are receipts for new plugs fitted just a few thousand miles ago, I can't find any receipts for spark plug leads though and they are tatty looking. The plastic guide is broken in half at the rear end and not bolted up at the front end (someone has been pretty rough with it!) so the plug leads are free to move around quite a bit... Are the plastic guides still available from somewhere ?

The ICV is definitely non functional at the moment - disconnecting the connector does nothing, if I disconnect the air hose to it and block it the idle drops from 950 rpm way down to about 400 rpm (amazing that it can still idle that low without stalling but it does, and quite smoothly!) and I don't hear any air leaks so its definitely the ICV not an air leak, so it will have to come out to be cleaned.

David seems to think there is a way to remove it without removing the whole manifold but it looks tricky to me as it still has the original crimp hose clips... so I'll leave that until after the MOT next week.

I may kill a few birds with one stone by taking the manifold out, fixing the ICV, changing the plugs and spark plug wires and checking the rear bank for oil leaks all at the same time.

What were you doing to the rear brakes?

Just the usual - a visual inspection, squeezing the pistons in a few times, removing the pads to make sure they aren't seized to the callipers and bleeding them.

The good news is there is absolutely nothing mechanical wrong with the rear brakes. The callipers are straight, the discs are in good order, the pads have nearly full thickness, the pistons were already nice and free and so were the pads, all that was wrong was there was loads of air in the lines - probably from a punctured anti-sink sphere.

The brakes are top notch now with no lifting at the rear - in fact they're more sensitive than the S2 even though it has new discs and pads on the rear... I suspect they'll get air in them again from a bubbling sphere, but not until after the MOT... (And soon after that it will get new spheres)

[CitroJim]

it's starting to feel like "my" car now.

You have no idea how happy I am to hear you say that

That's two of us

[Mandrake]

it's starting to feel like "my" car now.

You have no idea how happy I am to hear you say that

That's two of us

It took a few weeks for the silver one to start feeling like "mine" so this is fast indeed.

[Mandrake]

Right, a quick summary of today's efforts out in the burning sun at 27 degrees.

As mentioned earlier, changing the map sensor and resetting the ECU seems to have solved the throttle lag and sluggish high rpm performance, and also eliminated the power spike just above 4000 rpm. It goes like stink now, as I hoped it would. The engine has a soft but audible V6 "roar" to it now when you put your foot down but is still very very quiet inside compared to the old one.

Two new wiper blades were fitted (a spare but new pair donated by Trainman ) and the spray nozzle aim adjusted so the water actually lands on the windscreen.

The broken drivers door rear view mirror glass has been replaced - getting the old one out wasn't difficult but fitting the new one was challenging, in the finish some advice to put a bit of lubricant around the ring and squeeze quite hard did the trick! Only problem is I think I got a tiny bit of silicone on the glass which I'm having trouble cleaning off - so there is a slight milky haze to the mirror...

The rear brakes have been checked and bled and the brakes are now working beautifully - in fact they're too sensitive and finicky - I think I need to do the spring removal mod at some point - for some reason my S2 didn't seem to need that mod but all the S1's I've driven did need the mod.

A few things I've found today -

The aux belt is all cracked so will need replacing quite soon.

The plastic guide for the spark plug leads is broken in half and is not bolted in.

The rear height corrector rear facing end cap rubber is blown up like a balloon about ready to burst! In all my years of Citroen's I've never seen this before - if you push on it with your finger you can feel there is a lot of pressure in it but it's not (yet) leaking. Does this mean the low pressure leakage return line is blocked ?? If so I'm surprised the hose hasn't blown itself off the side of the height corrector. Thoughts ?

I've looked more closely into the sphere situation and I've come to the conclusion that the rear strut spheres are well past their best too - they are actually quite rusty on the sides when I look closer and when driving the car I can tell the rear is a lot stiffer than it should be even in the "hard" mode, to the point where the car is dangerous to drive at 60mph on a bumpy country road, as it is bouncing about all over the place, which does NOT happen in the hard mode when the strut spheres are good.

The only two spheres on the car that MIGHT be OK are the two front strut spheres, and even they might not be great so I'm afraid it looks like it needs a full set of eight spheres...

Both height correctors work beautifully (balloon shaped rubber end cap excepted) and respond quickly and accurately to small height errors - also the car both lifts and falls very quickly at both ends with the manual height lever. There are no creaks or groans from either front or rear suspension. The front ride height seems a wee bit high (seems to be common on Xantia's for some reasons) so might need tweaking a bit.

The rear suspension arm bearings have grease on the pivots and show evidence of having been replaced in the past. There is a bit of quite worrying rust on the rear strut feed pipes near where they go into the nut - its literally flaking away so I might need a new pipe there soon. One of the unions into the height corrector has almost completely disintegrated as well. Other than those rust under the car is pretty minimal.

Both plips are now programmed and work perfectly without even changing the batteries.

Next up is an MOT, hopefully it will pass first time then after that will come a set of spheres and then all the urgent stuff will be done.

[DHallworth]

Give your rear strut feed pipes a rub down with some wet and dry paper, Simon. Get all the loose corrosion off them and paint them with some Hammerite.

Might be worth doing this before the MOT incase they give you any problems on corroded pipes like they can brake pipes.

David.

[Hell Razor5543]

It sounds as if you are having fun with the new V6 Simon (and I mean fun in a good way).

Re my spoiler idea. If the paintwork is as good as Jim says, it is possible you will want to get the scuffs sorted. If you were to remove the spoiler off 'Problem Child', and then sand and prime it, it might be possible for the bodywork guy to re-spray it to the right colour while sorting the scuffs. He would have had to get enough paint to sort out the scuffs, and would probably have some left over.

[Mandrake]

What's the 'spring' mod for rear brakes? Never heard of that one.

It's not specifically for the rear brakes - between the brake pedal arm and the brake doseur valve is a plastic capsule with a spring inside it to make the brake pedal feel mushy like a vacuum servo system.

You remove the spring and replace it with an equal length of metal tube, thus restoring proper Citroen brakes.

My S2 didn't seem to need this modification but all the S1 models that we've had in the family have benefited from it. It makes the brakes more responsive but at the same time smoother and easier to control accurately. Search for the "silly spring" mod on the forum...

If you have a suitable piece of hollow tube it can be done in about 5 minutes and reversed as easily if you don't like the result.

[Mandrake]

Opps - filled the tank up tonight and thought it was taking a bit more than I expected to brim it, looked down on the ground and saw fuel running out the bottom of the wheel rim and on the ground. It only started leaking when it brimmed so I assume one of the vent return hoses is leaking.

By the time I got back home and lifted it up to see the fuel had evaporated and left no trace but when I pulled the wheel arch cover down a bit I see two hoses going into what I think is the filler assembly - both are plastic lines (?) with about a 50mm rubber joiner hose with a hose clamp on each end of the joiner - one of those rubber sections is perished so I assume that's what's leaking. Anyone know the inside diameter and whether I can replace it with standard diameter "fuel line" hose ?

Oh, and I must be a glutton for punishment, I updated the engine ECU firmware tonight It was running an older version than the other car so I thought why not. The only comments related to the firmware update are that it addresses stalling issues when the air con comes on, but I could swear that its more zippy after the update....

The gearbox ECU firmware update was staring me in the face too but I'm going to resist the temptation - as I know the gearbox ECU update adds the very annoying "hold first until 3000 rpm on a cold engine" depollution routine - which I hate with a passion on the old car after I updated it! (And once you update it you're stuck with the new version with this "feature" forever...)

I did give it an auto adaptive reset though...