All Things V6...

[Mandrake]

Just how essential is it to have the manual version of the Engine ECU for a manual conversion I wonder ?

Yes, the automatic version of the engine ECU has extra code (presumably) in it to talk to the gearbox ECU that isn't there or is disabled in the manual ECU, however most of the information flow is in the direction from engine to gearbox:

* Throttle opening percentage (sent to pin 38 on the gearbox ECU)
* Calculated engine torque (sent to pin 39 on the gearbox ECU)
* Engine speed (sent to pin 40 on the gearbox ECU)

The only information sent from the gearbox ECU back to the engine ECU is the torque reduction request signal sent from pin 51 of the gearbox ECU.

This tells the engine ECU to retard the timing by approximately 20 degrees during a gear change to smooth gear changes and reduce strain on the gearbox by not having full torque applied while clutches are engaging/disengaging...

These signals from memory are all simple pulse width modulated square waves not encoded digital data, so in the case of the torque reduction request signal, potentially easy to spoof with a very basic PWM circuit, if required.

So if the two ECU's can't communicate with each other, what happens ? Does the engine ECU bring on the EML light ? Does the engine ECU default to full torque reduction retard all the time for safety ? I suspect the answer to both is no.

An easy way for you to test David would be to unplug the fuse for the Gearbox ECU on your donor V6 car, and after a short test drive (in hydraulic 3rd/reverse fallback mode) check whether the EML light is on, then run a Lexia session on the Engine ECU - you might see a failed to communicate with gearbox fault code logged, but that's probably it. You could also check in the parameter measurement section under Ignition and watch the torque reduction retard figure while driving to see if it is applied all the time compared to when the gearbox is connected and communicating.

My suspicion is that the automatic version of the Engine ECU will work fine without the gearbox connected, worst case scenario is that you might need a small circuit to feed a suitable PWM square wave into the torque reduction input to tell it not to retard the timing.

Is there anything else different between the two versions of the ECU, such as the actual tuning (mapping) of the engine ? Seems unlikely, when its an identical engine.

If you could use the engine ECU from the donor V6 could you also use the CPH and keys from it as well and avoid the whole reprogramming nightmare ?

[DHallworth]

Simon, sorry I've not replied, I hadn't seen your post. I've got a feeling it might be easier to get the ECU unlocked then it would to try and find a way of feeding it with a false signal to be honest.

My Activa is going for it's MOT on Thursday morning at 08:30. So I put it in the workshop to change the tyres over. I'd bought these supposedly brand new on eBay around 18 months ago and left them under a blanket at the back of the workshop, out of the way, out of the sun and kept covered thinking I'd get to them when I needed them. I fitted and balanced the first one without a problem, fitted the 2nd one and as I started to inflate it I could hear air passing through the sidewall. Upon closer inspection there's a pin hole in the sidewall allowing air out so the tyres a write off

Anyhoo, after a bit of t'internet browsing I've managed to find a brand new spare wheel and tyre from a car that was written off for £40 so it's not been to bad.

A friend of mine arrived today as I was checking all the bulbs and making sure the indicators were still orange etc and asked me when I last used the car. I told him I thought it had been a couple of years, he then asked why I liked it etc etc and was quite surprised when I told him about the trick suspension and even more surprised that I was going to the effort of changing the engine.

He then pointed out that the tax disc on the car expired in 2008. So my guess of a couple of years is way out! The cars been kept covered, started and allowed to warm through and then taken for a run down the yard and back again but it's not actually seen the open road for 5 years.

Anyway, I'm pretty confident that it'll pass it's MOT on Thursday and I'll be able to give it a good run soon enough. I'll not tax it immediately, I'll do it from 1st May so that I don't loose half a month.

There's a nice 70 mile run that takes around 2.5 hours if you don't stop. I quite often take them on after they come out of winter hibernation. A nice balance of main roads, fast roads, decent places to stop and go for a walk and it's just a nice run to go on and spend an evening out with Cheryl on so it'll be going round there too.



David.

[Citroenmad]

5 Years without a decent drive in an Activa! I just couldn't, I start getting fidgety if I haven't driven mine within a few weeks

That looks like quite an entertaining route

[CitroJim]

5 Years without a decent drive in an Activa! I just couldn't, I start getting fidgety

Gosh Same here, I don't know about fidgety, I think I'd be suffering a lot worse than that..

Good luck for the MOT David although I'm sure the car will sail through and do enjoy driving it again...

That route looks lovely

[DHallworth]

That route looks lovely

If you still fancy a week up here in May, Jim, I'll take you for a run on it if you wish.

David.

[DHallworth]

Well after a gentle warm up and a bit of a blast on the 11 mile run to the MOT test this morning the Xantia was running beautifully.

I'm also pleased to report that she passed her MOT without any big issues. Had to explain to the tester what all the grease was on the suspension linkages though as he thought it was a fluid leak but when he saw it on both front and rear he chilled out.

4 advisories:

Front balancing ram damp
Rear balancing ram damp
Centre section of exhaust is showing signs of corrosion
Hand brake just met requirements

So, nothing major and a couple of jobs to be getting on with when the engines changed. Time to use the parts I bought two years ago and implement a CitroJim repair to my Activa rams I think!

I had totally forgotten how much fun they are to drive though. Had a thoroughly enjoyable 15 mile back road run home.

David.

[hattershaun]

Well done on passing the MOT. You may find if you start using the car the Rams will dry themselves without needing any repair. Mine weep a bit when not used much.
So, now's the time to get that 4 cylinder lump removed from under the bonnet to make way for a V6.

Re: the V6 engine ECU. The engine will run fine with the ECU that's intended for an auto gearbox even if you have a manual, as I ran my car like that for a while after conversion. The only noticeable difference was between 1000 to 1500 rpm when re-applying the throttle after having been on the overrun, there was a moment's jerk/hesitation. I got used to driving round it. I bought a second hand Peugeot 406 V6 manual ECU, there's a chap selling spares on eBay from all the cars he's broken up. Citroen Service shows the part numbers for both, BVA is auto gearbox BVM is manual gearbox.

[DHallworth]

Thanks Shaun.

Can you remember where you got your ECU unlocked?

David.

[CitroJim]

Great news on the MOT David and I can echo Shaun's comments on rams drying up with use.. Mine often do...

I'm delighted you are enjoying the car again they are addictive

That route looks lovely

If you still fancy a week up here in May, Jim, I'll take you for a run on it if you wish.

David.

Sadly, for a couple of reasons David, it's becoming increasing unlikely I'll be able to do so. It's not that I don't want to, far from it, but there's a couple of spoilers that might well scupper it

[DHallworth]

That's a shame Jim, don't worry about it. If there's anything I can do though, you know where I am

Had a nice easy day today as tomorrow is going to be a long one. Leaving home at 3am to be in Cairnryan by 6am for the 7am ferry to Belfast. The return leaves Belfast at 19.30 and puts me into Cairnryan at 2200. Add 3 hours to that to get home and it's going to be a 22 hour day so really didn't want to do to much today.

I ended up washing my Range Rover, Luke's new V6 Xantia and my Activa.

Here's a couple of pictures of the Activa:

Before:



After:





I changed the indicators in the wings from the orange plastic ones to the clear ones whilst I washed the car today as I think they look much better.

Anyway, it's a bit of a sad day here today as the Xantia V6 that we've owned for 6 years is finally leaving, all washed up she now sits strapped to the trailer awaiting her maiden voyage across the Irish Sea. Really hope she behaves for Luke like she has done for us, she's been a great car.

Luke's going to have the pleasure of watching her cross the 50k mile mark shortly too.



That's all for now, will update this with more goings on over the weekend as the Xantia is dropped off and the C5 is collected

David.

[Citroenmad]

Your Activa looks very nice there, pleased it went through its MOT ok

will update this with more goings on over the weekend as the Xantia is dropped off and the C5 is collected

Optimistic, I like it!

[hattershaun]

Thanks Shaun.

Can you remember where you got your ECU unlocked?

David.

There's a company just round the corner from BL that do all sorts of work on ECUs and electronic diagnostics etc.
Think it cost a beer token or two.

[DHallworth]

Well, today has been a long day. Up at 02:45 this morning to get ready and left the house at 03:30 to catch the ferry.

After a very enjoyable and successful day, Luke is now the proud owner of a Xantia V6 which He seems to have fallen in love with as soon as he saw it, never mind drove it. It was nice to know that cars gone to a good home.

The C5 was a little bit more troublesome though. We had a quick fiddle with the Lexia and managed to change all of the settings back to English so you can now understand what the car is saying. Testing all of the actuators for the suspension was successful though, everything seemed to fire when clicked on in the Lexia. Eventually the suspension did begin to raise on its own too. Problem was that when testing the pump runs for a few seconds and that's it. As a result we couldn't get it high enough that way.

We managed to get a jack under the car after using a long piece of wood as a lever to lift it off the ground, we then pulled the wheel down and placed a block of wood between the drop link mounting on the strut and the strut top. This gave is enough clearance for the trailer. It's now sat on car deck 5 of the Stena ferry heading to Cairnryan.

When you try and start the C5 there isn't a click or anything from the starter. The lights on the dash go out as if it was trying to start then the computer says entering Eco mode. I also noticed that there's not a drop of coolant in the bottle either so I really hope nothing sinister had happened before it was parked up.

Tomorrow I'm going to try connecting a light bulb to the starter motor connection. I theory when you turn the key the light bulb should then light up. If this lights up then all of the wiring is fine and the starter is knackered. If it doesn't then we know there's a wiring/electrical issue somewhere. I tried a jump lead between the engine and battery negative today in case it was a bad earth but this made no difference.

Fingers crossed its nothing to complicated!

Right, I'm off for some kip before I get off the boat at 2200 and face the 3 hour drive home.

David.

[CitroJim]

Great stuff David, enjoying reading this immensely and delighted Luke is happy with the Xantia

You know, the symptom of what you have when trying to start the C5 is exactly what you'd get if the start inhibit relay was not working - the one that make it possible to start only in P and N...

I'd be tempted to run a sire direct from the starter solenoid and flash it to the battery and see if the engine will then turn over and start thus taking the start inhibit relay and all ignition switch wiring right out of the equation.

Looking forward to the next instalment

Buy the way, the Activa looks gorgeous

[Ben82]

You know, the symptom of what you have when trying to start the C5 is exactly what you'd get if the start inhibit relay was not working - the one that make it possible to start only in P and N...

Not 100% exact though, the computer will tell you that's the fault, although it could be the Ecu literally has its wires crossed and the "not in p" message is confused with the timer running out for Eco mode. Not sure how though.