All Things V6...

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

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DHallworth
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Re: David Hallworth's Blog aka All Things V6!

Post by DHallworth »

Well after a quick dismantle that should have taken 48 hours at most, over a month later I have finally finished stripping our old HDi Exclusive that I bought back form Jim on the other side of Glasgow. Today it made it's last ever journey on the back of the trailer to the scrap man.

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A few years ago when I wasn't using the Activa I was putting a new set of spheres on the HDi. I found that the front electrovalve was knackered. As I wasn't using the Activa I swapped them over and it sorted out the HDi. I'd actually forgotten I'd done it until it was put on the Lexia at BL Auto's after the engine swap was done! So finally, today, the Activa has been reunited with it's original electrovalve. I had it running on the driveway and cycled the suspension up and down a few times and I could feel the suspension was softer with the door open then it originally was.

A quick session with the Lexia and the fault had changed from a "Permanent" fault to an "Intermittent" one. The fault has now cleared as well and you can feel the car switching between hard and soft as it should when you're driving. It's certainly transformed the car.

The last time the Activa was out must of been about 6 months ago so today she's had a run and has performed faultlessly as always. This car never fails to make me smile, and I have absolutely no regrets whatsoever about spending the money I did on it during the summer.

David.

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Mandrake
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Re: David Hallworth's Blog aka All Things V6!

Post by Mandrake »

Glad to hear that the Electovalve swap has made an improvement David. :) Has the Activa had the diode modification done yet ? (On an Activa it's three diodes instead of two) If not it may be worth doing that as well.

There's two different ways the Electrovalves fail electrically - high resistance or open circuit diode, and high resistance or open circuit coil.

Both are caused by dry joints inside the brown plastic moulding sleeve that has the coil embedded in it. When the diode has a dry joint (or fails completely) an external diode as in the diode modification restores normal operation, however when the coil gets a dry joint it's curtains for the electrovalve... I've seen both types of failures before, and both are typically temperature sensitive where they start to play up when the Electrovalve gets hot.

I'm pretty sure my new V6 is sticking in hard mode at the front about 75% of the time too. It's usually ok from a cold start for the first 10 minutes or so but then starts to get very firm and fidgety at the front, "rocking" from side to side a lot over the undulations. (Usually a sign the car is soft at one end and hard at the other)

I haven't had a chance to try the diode mod yet to see if it responds to that but I suspect I need an Electrovalve. The funny thing is whatever the problem is does indeed seem to be temperature sensitive - I've noticed that when I drive in really wet conditions where the road is flooded and is throwing up spray underneath the car that the ride stays good - my theory on that is the road spray is cooling the electrovalve as dry joints are notoriously temperature sensitive...

I've seen the correlation between good ride and cold/wet road enough times now to know that something is going on... on a couple of occasions the road was dry when I started driving and the ride got fidgety at the front, then it started raining hard and we drove through flooded patches of road and the ride went soft again and stayed soft for the remainder of a longish drive across very wet roads! [-X

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DHallworth
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Re: David Hallworth's Blog aka All Things V6!

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Interesting theory on the reason for failure Simon. I've not done the diode mod yet. The HDi had the e-crofting box screwed in at the front which I forgot to remove actually.

It was a fairly rare colour Mike. Unfortunately it had been badly resprayed down the passengers side of the car where it had been keyed. The colour match was never right. Unfortunately I didn't notice it when looking at the car originally, I only saw it as I drove home in the passengers door mirror. Jim was also telling me it had welding done for it's last MOT and apparently was going to need more for this MOT so when the hydraulic pipe burst when he had it, it was game over. He'd already removed a fair few things, interior, injectors and some other bits and pieces to name a few before I got it back.

Was quite sad seeing it thrown away today as it had been a good car in the time we had it.

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BW
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Re: David Hallworth's Blog aka All Things V6!

Post by BW »

MURDERER!

Seriously though, the temperature theory seems to work for my car as before it got the diode kit it went hard sometimes but not all the time, so the cooling rain would explain that.

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Re: David Hallworth's Blog aka All Things V6!

Post by Mandrake »

BW wrote:MURDERER!

Seriously though, the temperature theory seems to work for my car as before it got the diode kit it went hard sometimes but not all the time, so the cooling rain would explain that.
I think the intermittent front Electrovalves are definitely temperature related - remember the Electrovalve is mounted down on the corner of the radiator so every time the radiator fans kick in it's being blasted directly by hot radiator air! [-X It's a fairly hostile environment for soldered connections, even if they are moulded inside plastic.

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DHallworth
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Re: David Hallworth's Blog aka All Things V6!

Post by DHallworth »

Well a great day was had at Glasgows French V6 HQ today...

Simon came down for a visit in his V6 Xantia and a friend of mine came to visit in his 205 GTi that has undergone a nut and bolt restoration and is currently running a Xsara VTS engine.

Simon managed to solve a couple of electrical issues he was having with it with the MAP sensor and Lambda sensors. It's a 306 GTi wiring loom and ECU connected to a Xsara engine and sensors so some of the plugs had been remade. Luckily it was just wires the wrong way around. The lambda sensor was odd, green went to red and red went to green, totally the opposite of what you'd expect.

We then got round to fitting the new exhaust to Simon's V6. The hangers were in the correct position on the back box but they weren't quite at the right angle. We heated them up with the oxy acetylene litany bent them the right way and fitted the exhaust. The new system was a perfect fit. It slid on nicely and the positioning of the flange on the centre to rear sections was perfect.

The lad who owns the 205 is also the same guy who does the detailing work for me :) As a result my Activa and 406 Coupe were given some much needed TLC. I'm pleased to report that both cars are now looking absolutely fantastic.

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We even managed to have a BBQ at the end of November due to the unseasonally mild weather that we are having at the moment...

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That's the Activa now in hibernation until Spring anyway. It's going in doors as soon as I've got a space for it, hopefully in the next couple of days.

Anyway, a great day was had by all as far as I'm aware. Can't wait to do it again now! :)

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CitroJim
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Re: David Hallworth's Blog aka All Things V6!

Post by CitroJim »

Excellent David, what a lovely day 8-)

I'd love to see some decent pictures of the 205GTi. It looks a very late one on a K plate...

lexi
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Re: David Hallworth's Blog aka All Things V6!

Post by lexi »

Ye gads. Coca cola, hamburgers, soft white rolls (wall filler) sugary tomato sauce and carcinogenic charcoal !

Total Geek food :shock: :lol:

Hell Razor5543
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Re: David Hallworth's Blog aka All Things V6!

Post by Hell Razor5543 »

While it might be junk food, it is also good 'bonding' food. It has its place, and yes, sometimes that is the bin, and other times it helps make the atmosphere at a get together.

lexi
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Re: David Hallworth's Blog aka All Things V6!

Post by lexi »

The only thing that will bond Al is the old Rusty Sherrifs badge ..................I have lost a few friends to massive constipation and anal stretch marks you know?
:rofl2: :rofl2:

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DHallworth
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Re: David Hallworth's Blog aka All Things V6!

Post by DHallworth »

There was no charcoal on sight... It's a gas BBQ with a cast iron griddle!

They were proper beef burgers from a butcher in North Wales and they were nothing short of superb!

Sugary ketchup... Yea, can't deny that one!!

:D

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Re: David Hallworth's Blog aka All Things V6!

Post by lexi »

Have just popped back from David's there to pick up something he brought back from Luke's a while back . Nice to see you again buddy. Good to hear that all are well up there . Joking on the food of course. Your Uncle Lexi will eat and drink anything...........except McDonalds :-D

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Re: David Hallworth's Blog aka All Things V6!

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Thanks to David for a very enjoyable day. :) My back is stiff and every muscle was aching this morning but that's to be expected from a few hours of bending over the engine bay of a lowered 205 for someone lazy like me whose body isn't used to doing proper physical work! :-D

The beef burgers were unusually good - so much so that after the first burger instead of taking a chance on the sausages I just had a second burger. :lol:

I was quite chuffed that I managed to solve not one but two engine management faults on the car, especially given it's a 205 that has a 306 GTi ECU and wiring loom connected to a Xsara VTS engine! :shock:

Turns out that as well as the MAP sensor the oxygen sensor wasn't working either - no wonder it wasn't running very well!

The issue with the MAP sensor turned out to be exactly what I anticipated based on the description of the problem - two wires reversed, in this case signal and signal ground. The connectors for the MAP sensor and oxygen sensor that come with the loom for the 306 ECU don't match the sensor connectors on the Xsara VTS engine so a different connector had been spliced into the loom for each one.

None of the colours of the wires match up either so we had to manually verify the correct connections. Because there was also the worry of a blown input on the ECU or a missing 5 volt reference I made up the following little test rig that morning before I went over: (Jim will get a chuckle over its simplicity)

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It provided me with an independent adjustable 0-5v source to simulate a sensor signal to the ECU. That way I can clip onto battery negative and probe each pin on the connector to find out which one responds on the Lexia when presented with a variable voltage. (Both MAP and TPS use a 0-5v range) The 100 ohm resistor on the wiper provides protection in case you touch the wrong thing like the 5v reference.

Using this we very quickly identified the correct signal wire confirming that the plug was wired wrong but that the input on the ECU was functioning ok. Phew! After swapping them around and terminating the wires neatly the car started and ran beautifully instead of stalling and sputtering. Success! Well, not quite! :twisted:

There had also been an oxygen sensor fault code so we started looking at that. When we first checked it it did seem to be working - the O2 voltage on the Lexia (in PP2000) would start switching between low and high after about 90 seconds, so everything looked normal at first glance. However when we started the car about 15 minutes later and checked it again the O2 reading on the Lexia stayed stubbornly at 0mV for over 3 minutes. Hmm....

If it had been working before the signal wires must be ok and its probably a heater fault causing it to warm up slowly, right ? That's the logical conclusion. Wrong! #-o

We checked the heater resistance - 10 ohms. Seemed a bit high to me but they do vary a lot from one type to another (one reason generic sensors are seldom ideal) so it was still a plausible value. I then used my backprobe test lead to make sure there was 13.8v at the heater connections with the O2 sensor actually plugged in - check.

Next I put my backprobe lead on the signal wires from the O2 sensor and hooked it up to my small scope, started it up and compared it to the Lexia reading and got a massive surprise! The Lexia was completely lying about the O2 switching! Both Lexia and scope started at 0v but after about 45 seconds the scope reading climbed to 750mv but the Lexia stayed on 0mv... then after about 90 seconds the Lexia started showing the O2 voltage switching between about 40mV and 900mV back and forth like you would expect it to but the scope was showing the truth that it was just sitting on a steady 750mV (rich) the whole time!

So the ECU was inventing O2 switching that clearly didn't exist, and it had fooled me at first... #-o This is known as "substituted data". When an ECU detects a faulty sensor it will switch into a "fall back" mode where it synthesises an approximate sensor reading from other sensor data and uses that in place of the faulty sensor. For example in the case of a faulty MAP sensor the TPS and engine RPM data can be used to synthesise a MAP reading that is good enough to make the car run.

The problem is not only does it use this synthesised data for itself - it will sometimes send that data to the scantool (Lexia) as if it is real data and not indicate that the data is made up, so beware! If there is any doubt the actual sensor voltage/waveform should be measured directly with a multimeter/scope to ascertain the truth of the situation. It was only my scope that revealed the lie that the Lexia presented us...

A bit of tracing of the wiring back to the ECU connector and we found that the signal wire and signal ground on the O2 sensor were also reversed - effectively feeding the ECU a negative signal voltage instead of positive...opps...

The reason for that was actually a good one - both the wiring loom belonging to the ECU and the sensor connector that belonged to the engine which had to be spliced together had green and red wires for the two signal wires and they were connected the "right" way around - it turns out that the colour coding on the two is different so we had to connect red to green and green to red to get the polarity correct back to the ECU! :lol: So apparently a 306 Gti uses opposite wire colouring to a Xsara VTS for the O2 signal even though the engine is the same... [-X

After reversing the wires and tidying them up the scope confirmed that the O2 sensor was now warming up in about a minute and switching healthily. The Lexia also showed normal switching, but that wasn't terribly useful when it had shown normal switching when the sensor was connected back to front and not operating!

After that success we then moved onto the exhaust on my car, but I'll post about that over in my blog. :)

All in all a very satisfying and enjoyable day. =D>
Last edited by Mandrake on 30 Nov 2014, 17:09, edited 3 times in total.

Hell Razor5543
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Re: David Hallworth's Blog aka All Things V6!

Post by Hell Razor5543 »

I will eat at McDonalds, but only the Deli of the Day (as they have to make it fresh). If you ever choose to get a KFC take a look for the ownership plaque. If it is owned and run by KFC (as opposed to a franchise) they have a strict, accurate food monitoring system. Once the chicken enters the broiler it is on the clock, when it goes into the warming cabinets it is onto a new, clean tray, and if it is still there after a certain period of time it WILL go in the bin (I used to repair/replace their IT and EPoS kit, and I saw this happen). They were also very conscious of the cleanliness of the kitchens (unlike some other fast food providers, in my experience).

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Re: David Hallworth's Blog aka All Things V6!

Post by lexi »

Thanks for the eatery tips James.......where did I get Al from?
Not around these places much and out of touch a bit. I only found out the other day that Srewfix was........not a dating agency :shock:

Simon. You are a whizz with the leccys. You'll be on a call if ever get CAN CLIP for Renault. :lol: