My 406 Break - bought it for work, but already love the car

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joydivision
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My 406 Break - bought it for work, but already love the car

Post by joydivision »

Hi!

I bought a 406 Break (2.1TD from 11/1997), as I had to change my car (due to work I have to take care of over the next months and also I've got two kids, so my previous car was really needing an upgrade in terms of space, and this one has LOTS of it). I've always liked the 406 (a friend of mine owned one, years ago), but hadn't met the TD (XUD) motor yet, only the HDI. Then this car came up and I bought it, it was cheap and has little mileage. I traveled quite some miles by bus to get it, as here where I live I couldn't find anything at a good price. When I tested it, I was really paying attention and had myself prepared (I've bought used cars before, and have some knowledge in mechanics and quite more in electronics, but still I'm not a mechanic), I did notice some little things which were not obvious, but I was quite convinced and bought it. I obviously couldn’t spot the hidden ones, though. The trip back home went fine, the motor seemed a little "slow", probably due to carbon build-up not having been driven well for a long time (was used for small daily trips) and maybe not having been taken care of that well. Just with the trip it became much more responsive, though. I then took it to a mechanic I trust and asked him to do the obvious stuff (oil change, coolant change, fuel filter, air filter) and also decided to do the timing belt. Turned out my insticts were right, the timing belt would have had 20 years and could have broken on the trip home, so much for the words of the seller: "the owner made all the normal maintenance". If leaving a timing belt for 20 years is normal, then I don't know... The mechanic unfortunately also noticed that the auxiliary belt hadn't been changed, either, and a few associated components were damaged (a roller, and a kind of spring, which was making a heck of a noise which I noticed but thought had to do with some plastic near the wipers). So, the bill was raising. Then he found a pipe that goes over the motor (it's metal) which was completely in bad shape, unfortunately costs around 100 euros... all together ended up almost 800 euros... but the car is running really well now, the 109 HP are clearly there, it pushes very nicely and sounds great, lots of torque. Just what I need. Also seems to be quite economic. Despite the age (and the less careful maintenance), I think I've got myself a nice car, I really like to drive it. The interior also is in a nice shape. The exterior it has some defects in paint, nothing really serious, except for a few spots of corrosion, but again not critical, all on a superficial level. Still, I will have to take care of them sometime in the future. Right now I've got other priorities - besides the 800 euros already spent, turns out the A/C wasn't repaired correctly (seller had changed the compressor on his expenses, and the system was working, but then stopped working, seems to have a leak) and also I've discovered quite a lot of really annoying small electrical problems since then, which I'm determined to fix, as I've got knowledge and experience in electronics, but I'm struggling a bit, although I already got myself a Haynes manual for this car and found a lot on the internet, but seems there have been like almost half a dozen different versions of the 406, at least what concerns the electrical systems... So, I came to this place (and a few others) to share my adventure with this nice estate and also seek some help from the more experienced. All in all I hope that this car will make still a lot of miles with me and my family and serve me well for the task I have on hands over the next months. Here are some photos. I will open several separate threads for the most important issues I'm in the process of solving. But this is going to be the working thread - I'm going to check the list here of issues to solve. Hopefully it won't be long until I have it all sorted out. Then in the future, if the car behaves well and I have more time, I might well decide to restore it in terms of paint and some other details. Let's see.
DSC_2954_.JPG
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DSC_2958_.JPG
I forgot to take a photo of the motor, will do that soon.
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Doggy
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Re: My 406 Break - bought it for work, but already love the car

Post by Doggy »

Hi & welcome aboard. 8)

That's a good looking 406 you have there, nice colour and with the sought after leather interior. I hope it serves you well for many years. :mrgreen:

I only had 2.2 HDi's, but my brother's first 406 was a 1999 1.9 TD which he really liked. I've never driven a 2.1, but owners always speak highly of them.

There is a good deal of information on the site which you may find easily with the search function, but don't hesitate to post any questions you have - we are not one of those forums where users are criticised for asking common questions. There's not so many active members nowadays and sadly few of us still have a 406 but there is still a fair amount of know-how there for the asking.

Service life of timing belts changed a few times during the production run, but was always in the range 50 - 90k miles, or 5 years. It is good practice to replace the auxiliary drive belt, idler and tensioner pulleys at the same time, (but to be honest I only ever did the whole set at the first timing belt change on both of my 406's).
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
dirtydirtydiesel
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Re: My 406 Break - bought it for work, but already love the car

Post by dirtydirtydiesel »

:arrowu: +1 on what Dogslife said :cheesy:
Oh & welcome.

I didn't read all your post (because of how you had typed it, it started to hurt my aging eyes :wink: )

But 20 years is too long by at least 12 year's, I do hope you changed it before you used it.
2002 110 HDi estate, Rapier in monaco blue! ( found quite a bit more power :cheesy: ) SOLD I've sorted the airbag light :cheesy:
1998 3.0 V6 SE coupe in Diablo Red ( my baby ) sold
2006 206 1.4 16v sport in Aegean blue ( wife's shopping trolley :roll: )

2006 BMW e61 535d m-sport :supafrisk: run's for cover :lol:
joydivision
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Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Thanks for the warm welcome :)

Thanks also for the hints about the timing belt service interval, I was aware of it, though, so yes, when I sent it to the mechanic, I asked him to change the timing belt (also did water pump and tensioners, pulley). He confirmed the belt would have 21 years and showed it to me... :shock:

Sorry for writing long posts, I can't help it, it's always been like this since I can remember, I try to be as short as possible in writing, but turns out too long... :roll: This one will be an exception though, because I will come back here and edit it, it's like a working thread...

So, after having taken care of the important and urgent maintenance in motor, as already mentioned, done very well by a mechanic a trust, here's the list of things to get done mostly by myself (it unfortunately might grow - I'm still discovering little hidden "nightmares" - seems that the car despite its good mechanic shape, little mileage and well cared interior, has been serviced with too much of improvisation and too little real fixes...). I will regularly come back here and edit when I fixed one:

- TO DO: A/C is not working (compressor engages if I fool the system bridging pressure switch, but no cold air, still have to check if there's any gas in system left, suspect it's a leak, as the seller promised to make it work and did, by installing a working compressor and charging it, but a week later it wasn't working anymore). This one I won't do myself, don't have the equipment or access to the gas, still have to find someone to do this...

- TO DO: Blower motor only works on high speed. This is caused by faulty controller module (so called resistor, it's not a resistor). I just bought new one (unfortunately before taking out the motor - turns out the motor is different, has control module on board... now two options: repair or replace on board module or rewire with new module (found pinout looking at a video of a Megane - uses same module). But there's one more scary issue: there's a wiring hack that was made - the original power cables for blower were cut and the cables were connected to other thinner cable. Scares me a little to drive that powerful motor on such small cables... :( also don't know if they work for the control module. Have to check all this. Maybe rewire. This is important, as I want to have the A/C fixed... (might open separate thread in correct section with photos).

- FIXED PARTIALLY: Electric mirror control was not working. Took control switch out and dismantled it - was fully oxidised, cleaned it, good as new (will post photos when I can, don't have them right now). Still wouldn't work. Took out one mirror - turns out they DISCONNECTED the wiring. Connected it - woha! That's strange, now driver's mirror would go crazy when turning ignition on. After that, manual electric control would work nicely, still only on driver's side. Discovered they are linked to memory function of electric seats (ECU under driver seat). Don't have time or expertise to mess with such ECU. SO: installed a quick hack which made at least drivers mirror be adjustable: a button installed in plastic triangle cover of mirror allows disconnecting the control, so that you can have it off by default (no more crazy movement when starting the car), but when car is running, you can engage the control, adjust the mirror as you want, and turn the switch back off. Works great! No luck for passenger mirror, seems they disconnected it somewhere else! Anyone knows if there's additional connectors? Maybe in door? Seems there is no power getting there. So, I still have to fix passenger mirror... (might open separate thread in correct section with photos).

- TO DO: RPM gauge in instruments cluster is not working. For economic driving (and safe acceleration) it's useful and I really like it, so I have to fix that. Might be just a bad connection.

- TO DO: exterior temperature indication not working (shows three dashes) - might be the sensor, as it's in passenger mirror and that's the mirror that's still not working. One question: does anyone here know if that temperature measurement is really of any importance for the A/C control? this one has automatic control with temperature adjustment. if it's of any importance, then this is of higher priority, as I need A/C. I'm also not sure if the is only a multifunction display for temperature and radio of if it's the trip computer (then it's not working - or it doesn't have the button on command switch on steering wheel column).

- TO DO: multi function display and clock have no back light - install new bulbs.

- PARTIALLY DONE: change the radio for aftermarket Sony with CD which I had here - the original is only cassette. Did the change today, bought the nice adapter frame and correct wiring adapter. Nice job, BUT: speakers in front doors sounding distorted and in rear no sound at all (maybe no speakers installed? have to check). Tested the radio with known good speaker and it's fine on all 4 output channels. Will take speakers out of doors to inspect them but probably need new speakers... tweeters sound fine, fortunately.

- FIXED: locks of the doors where "spinning freely" sometimes when you try to lock/unlock - followed advice on internet, sprayed WD-40 inside, they stopped doing it.

- PARTIALLY FIXED: Hood mostly doesn't open correctly (gets stuck on right safety hook, which is stupidly annoying and really tough to get past sometimes!). First thought it would only need lubrification, but no, found a broken spring. Installed a different spring I had lying around here, seems to work, but still needs some improvement (sometimes the spring falls down).

- TO BE FIXED SOON: another one with the hood - after staying 5 days at the workshop for timing belt and all (probably hood open all the time), the gas cylinders that hold the hood open gave up their ghost - they are leaking oil and hood doesn't stay up for more than 2 seconds... ordered a set of new ones from EBay cheap, but they will take at least 2 weeks to arrive... so annoying!!

- TO DO: drivers electric window elevator works, but the automatic mode is gone, and when closing the window, it goes in steps, you have to press button like a half a dozen times to get it up - I suppose that would be a fault in the button? Checked with local parts store - this one is a rare version which they don't have aftermarket, only original, which costs 40 euros :O :O, so for now it stays like this, but I might try to repair the switch (which is a gamble, sometimes that can go wrong and then I can't operate the window!!) or maybe I can find a cheaper one on EBay. Or is it NOT the switch? If anyone knows this problem, would be helpful.

- MAYBE: electric sunroof doesn't work - no response at all. Might just be a fuse or connection. Not a priority.

- LATER (for the mechanic): small oil leak behind the motor somewhere close to the turbo, hard to get to. Only drops very slowly (I'm checking oil level often!), so not really a problem (except for the environment :( ) , but maybe a problem when it will go to inspection (MOT you call it? here it's annual inspection).

- LATER (for the mechanic): rear brake discs are worn (didn't spot that one when I bought it), that's why the handbrake even fully adjusted to maximum has to be pushed hard to secure the car well on a hill...I always leave it in gear therefore.

- MUCH LATER: there are a few small corrosion spots on exterior paintwork. For now I won't invest in new paint for these panels, but I might look for a way of at least stopping the corrosion. Ideas welcome (might open separate thread in correct section with photos).

- WON'T FIX: on cold start, this car has to be "tricked" or "helped" or whatever you want to call it. Discovered this solution on the internet, seems to be related with the Bosch pump, and it's a great tip because solves the problem I only discovered when I got home and started the next day: without the trick, it has a hard time to get started on cold start - more than 10 seconds, then white smoke and rough idle, might even cut out again. On warm start never fails, turns on in 1 second. I searched this on the net and found out that this means cold start fuel advance correction is not working (or not implemented? Bosch swap?), but an easy trick solves this: just press throttle pedal down a little to around 25%, maintain it there and then turn the key (after having the glow plug light go out, obviously) - it will start in not more than two or three turns when cold, without any white smoke and no rough idle, if 2 seconds later you take the foot off the pedal. This doesn't need a fix, just have to teach this to my wife who might sometimes need to drive it...

So, that's it (for now). You can already see that I had little luck regarding the electrical system :( but I'm still lucky as I've got knowledge in this field...
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Doggy
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Re: My 406 Break - bought it for work, but already love the car

Post by Doggy »

That's quite a list.

Once you have resolved the quicker solutions, you will probably get more helpful replies if you start a new thread for each of the remaining items, or groups of things that are related to each other.

Some short answers or clues on where to find them:

A/C
You can check if there;s any gas in the system by depressing the central pin on either filler valves, if there is any gas you will hear a distinct hiss.
Sounds like you have a small leak somewhere, the recognised method to trace is to have a specialist fill with a gas/dye mixture that leaves am obvious green stain around the leak. It works, but the one time I did it it cost about 50€.
Later I managed to remove the tyre valve adapter from a large cycle pump and fit this into one of the filler valves. I slid a cable tie into the end of the hose so it would depress the valve plunger allowing air to flow into the A/C system. (Needed 2 people to hold hose onto the valve and work the pump).
I was able to get a little pressure into the system and listen for the source of the leak. Crude, but cheap.

BLOWER
Easiest solution to the wiring problem might be to remove the connector and a section of the wiring loom from a scrap vehicle. Otherwise replace the undersized wires, but I would try to resolve the speed control issue first so you know the connections are correct before you make a permanent job of it. I don't really know how the speed control works on your car - later cars with climate control have a separate solid-state speed controller, (main transistor usually fails short circuit giving full speed only). I think my brothers earlier, basic specification car had a resistor arrangement of some sort, but his problem was overheated/damaged connections at the blower motor.

MIRRORS
This may help.viewtopic.php?f=3&t=25616&p=255689#p255689

RPM GAUGE
I believe there is a common problem problem with pre HDi diesels, but have no personal experience. I think there is a module, possibly on the back of the clocks, that converts pulses from a sensor on one of the injectors to a variable voltage signal for the gauge itself. I found some info with a quick search viewtopic.php?f=3&t=13536&p=123990&hilit=tacho#p123990
If you try similar searches you may find a better answer.

ELECTRIC WINDOW OPERATION
Try this: viewtopic.php?f=3&t=23609&p=240290&hili ... ow#p240290

HANDBRAKE
My 406's had rear discs with a small brake drum for the handbrake - you will find many posts relating to this issue, but also check out info about the backplates before you strip anything down. As you say, you can leave it in gear for now.

COLD START
I thought the 2.1 had a Lucas injection pump?
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
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steve_earwig
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Re: My 406 Break - bought it for work, but already love the car

Post by steve_earwig »

Hi there! That's one nice looking 406 8)

I think Doggy has most of it covered. Rev counter - The problem on D8 (BVM ML5T - equipped cars) was with the speedo, expensive module job. I've not heard of a rev counter dying, hopefully it is a connection. Handbrakes can be lousy, it's a set of shoes inside the disk and if it's all not in top condition and perfectly adjusted it's rubbish. Not really a problem until your safety test. External temperature gauge, the a/c only seems to use this to turn the a/c on when there's a certain (lordy, my memory :( ) difference between set temperature and actual temperature, to be honest I always found it a nuisance - I do not need the a/c on in the middle of winter :roll:
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joydivision
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Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Doggy wrote: Sun Jul 04, 2021 9:32 am
Once you have resolved the quicker solutions, you will probably get more helpful replies if you start a new thread for each of the remaining items, or groups of things that are related to each other.
Yes, definitely am going to do like that.
Doggy wrote: Sun Jul 04, 2021 9:32 am
Some short answers or clues on where to find them:

A/C
You can check if there;s any gas in the system by depressing the central pin on either filler valves, if there is any gas you will hear a distinct hiss.
Sounds like you have a small leak somewhere, the recognised method to trace is to have a specialist fill with a gas/dye mixture that leaves am obvious green stain around the leak. It works, but the one time I did it it cost about 50€.
Later I managed to remove the tyre valve adapter from a large cycle pump and fit this into one of the filler valves. I slid a cable tie into the end of the hose so it would depress the valve plunger allowing air to flow into the A/C system. (Needed 2 people to hold hose onto the valve and work the pump).
I was able to get a little pressure into the system and listen for the source of the leak. Crude, but cheap.
That's a neat tip, but I think I'll better take it to someone with all the equipment, as it might very well need the vacuum aspiration and oil added to compressor and all that.

Regarding the blower, yes, it's a solid state module fitted to the blower motor assembly, and it's defective, I tested it yesterday (strangely enough it's NOT the transistors that failed, it's another small component under the PCB, as it's really tough to disassemble, I'm just getting a new one. Going to fit it today, hopefully will be fixed. I'm going to look into the wiring question, but I think wire might be ok if not run much at high speed...

About the mirrors: drivers mirror might very well not be of the "memory" type, so would explain behavior. But I don't care to change the mirror for this, so the solution I found is good. the other one is not normal though so must be wiring problem, as also the temp. sensor doesn't work.

about the electric windows, thanks, very valuable info, will take care of it, probably will solve it.

Thanks for the very good thread about speedo and rpm counter, I suspected exactly this, so defintely will try this first (but when I find the time, not a real priority right now).

About handbrake, good to know, so one less thing to correct and good to know that I have to be careful with the handbrake of this car, always leaving in gear.

Yes, that's what I said, it normally has the Lucas pump, but this has the Bosch one, that's why I suppose it was fitted later and quite well adapted (runs nicely), except for the cold start advance correction...
steve_earwig wrote: Mon Jul 05, 2021 5:43 am Hi there! That's one nice looking 406 8)

I think Doggy has most of it covered. Rev counter - The problem on D8 (BVM ML5T - equipped cars) was with the speedo, expensive module job. I've not heard of a rev counter dying, hopefully it is a connection. Handbrakes can be lousy, it's a set of shoes inside the disk and if it's all not in top condition and perfectly adjusted it's rubbish. Not really a problem until your safety test. External temperature gauge, the a/c only seems to use this to turn the a/c on when there's a certain (lordy, my memory :( ) difference between set temperature and actual temperature, to be honest I always found it a nuisance - I do not need the a/c on in the middle of winter :roll:
Thanks for the info, especially about the temp indication and A/C. The speed gauge sometimes sticks on low speeds. But I just read the thread doggy linked to, and seems like this can be fixed by resoldering instrument cluster PCB.
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steve_earwig
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Re: My 406 Break - bought it for work, but already love the car

Post by steve_earwig »

Ooh, interesting about the Bosch pump, the Lucas one probably died and that was the cheaper alternative. I'd have thought from a 1.9 td but it could be from an XM as that 2.1 td had a Bosch pump.

Good luck with the fixes! It will be worth it :wink:
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joydivision
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Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Good news: blower is fixed, working great on all speeds now! :cheesy: . Was quite an adventure, though. I'll post the story in a separate thread in right subforum, as this may be really useful to other people. And so I only now noticed that this forum doesn't allow editing your posts later... so I can't edit the post saying that it's fixed... :supafrisk: :lol:

Regarding the blower: it was just a not connected cable! the blower motor is not exactly the right type (found out it's from a Xantia) and it didn't come with the connector for that cable which my 406 has (and that works as a feedback control wire for the head unit to know that the motor is in fact spinning when controlled by PWM signal pulsing the ground connection), so they left it unconnected, which made the speed control not working anymore. I was always looking at the wrong culprit (the control module). But more to this in the thread that I will open.

So, the list is getting smaller, but still long enough. I contacted a local A/C specialist who was recommended (hard to find one here...) but their machine is being repaired, so only next week... Now, I've noticed the speedometer is starting to fail (stick) more often, sometimes for large seconds or even minutes, especially at lower speeds. This is annoying (and might even get me a speeding ticked, would be the first in 17 years that I've got my licence, although I'm not really that driver who uses to stick to speed limits precisely...) and I need to get it fixed, this will be done together with the RPM meter (which is dead right now), have to find time to take the instrument cluster out and refurbish it :)

Otherwise the car is behaving nicely, now that I got the cold start thing sorted out (with the trick), it never fails to start quite quickly, and when it has been started once and been driven a little, all the other starts during that day are really, really prompt.

Today, I learned that I can't trust the fuel gauge too much. I almost ran out of fuel. Or at least I believe it was that, as I can't imagine any strange problem causing this and happening only once, and only after doing more than 1000 km with the car already. I was close to 905 km since I had the fuel tank filled (gauge was showing almost half of the last quarter, no orange light on yet), when I was going down a hill, suddenly the car lost power and speed and battery symbol went half on, then I pulled over and the motor was off (noticed it first due to lack of steering assistance and the radio beeping (it's a Sony, lol, they do that when switched off ignition). And yes, when I turned the key, it started right away, but the orange fuel reserve light was on, although the gauge was still in the same place, about half of last quarter. Luckily a gas station was really close, so I carefully drove there and got some diesel. Car has been going perfectly well after this. I noted down the litres I put today, tomorrow I'll fill the tank at a cheaper station I like to go to and make the calculations for average mpg, and there I will see if my suspicions about the fuel gauge are right.
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Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Oh well, it's not the fuel gauge and it was not lack of fuel. Today I filled the tank and it took only 60 litres, so would have had about 10 litres in it if I have the tank size correct (70 litres, right?), and shortly after, it did it again, cut off during driving. This time I observed more carefully and actually didn't pull over, just left the car running free, put clutch down and cranked it and it started right away, everything back to normal, didn't do it again after since then. What I observed while it was shutting off: the fuel gauge went immediately down to zero and battery light went on, but dim, no other indication lights, the engine slowly died just like the other time (probably because it was running in gear with the fuel that was left in lines). I can think of two possibilities: fuel stop solenoid acting bad (this one doesn't have the emergency fuel cut valve that can be reset or does it?? it's only the 1.9, right?) OR, a problem with the ignition barrel switch making contact fail and letting the ecu think the key has been turned off to "accessories" position (where battery light is on and fuel gauge is off). What do you think?
I mean, it's not like the engine stalled due to lack of fuel, because I just tried it, stalling engine on purpose: the three warning lights and "STOP" go on, not like here, here it's only the battery light. So, what can this be? I wouldn't wonder if it's the ignition barrel switch: if I slowly turn the key a little bit from "crank ready position (warning lights on)" back towards accessories position, the lights will go dimmer and sometimes it will go to battery light (accessories position) even a little before the key gets to the supposed position. This means it's worn and making bad contact, right? I have to solve this one, could be dangerous if it cuts off during overtaking, for example.
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Doggy
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Re: My 406 Break - bought it for work, but already love the car

Post by Doggy »

Sounds like you are making good progress, well done.

You should be able to edit your own posts with the pencil symbol, (leftmost of the 6 icons on the right next to your username).

Regarding the fuel gauge and starting issues, it might be worth removing the gauge level sensor and fuel strainer assembly from the tank and checking the gauze is not blocked and the float assembly moves freely, (access under back seat).
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
joydivision
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Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Thanks. Still a lot to do, though, and seems other things appear out of nowhere :( but I'm going to get them sorted!

That's an idea, but means a lot of work and I don't feel it has to do with the problem - fuel gauge seems to work ok, it's not very precise (from full to half means quite a few more kms than from half to empty), but it doesn't misbehave otherwise. Also, the car doesn't have any real starting problems - the cold start issue seems definitely related to the way they installed the Bosch pump (no advance correction or fast idle of whatever they call it), and it's solved easily with the throttle trick, car starts fine always. This sudden cut off has started yesterday, has done it twice. Also I don't think it's fuel related, as the battery light goes on and the warning lights as when engine is shut off or stalls, they don't go on.

On another note, I was really pleasantly surprised by the MPG result for these 905 kms: 6,5 litres / 100 km! For me that's amazing for a car like this, couldn't ask for more.
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Re: My 406 Break - bought it for work, but already love the car

Post by steve_earwig »

That's splendid progress 8) I was just reading your posts, I do enjoy sorting out other people's "repairs" :roll:

HDi's usually had bad fuel gauges, I don't remember any issues with my 2.1td though. Maybe best not to trust it until you get to know it's, er, personaility.
Unskilled meddling sin©e 2007

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joydivision
1.8 16v
Posts: 78
Joined: Fri Jul 02, 2021 7:18 pm

Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

Thanks :) let's see if I can get sorted the cut off problem, don't think it was out of fuel, everything is pointing at the ignition switch - it really feels worn.
joydivision
1.8 16v
Posts: 78
Joined: Fri Jul 02, 2021 7:18 pm

Re: My 406 Break - bought it for work, but already love the car

Post by joydivision »

So, some worthy updates. First: I have no pencil icon. Don't know why, so I can't edit my original post. :roll:

Here's what I've done:
-- Fixed the clock illumination problem (bulb holder was gone - simply soldered the bulb with wires to correct points)
DSC_2994_.JPG
-- Took the instruments dash board out, took it apart and resoldered, measured everything, couldn't find any faults, had a better research on the net and found people fixing it by bending the pins slightly on which the needle meters go, to make better contact, I went even further and treated them with deoxit and fine sand paper (they were a bit oxidized), then noticed a problem with the flex cable (that's fixed with that metal piece) that makes connection from inner PCB to the flexible PCB. Decided to go around it and soldered 11 fine wires into place. A hell of a job, and it's not really neat, as to be able to take it apart again fully, they have to be unsoldered from the connector part (where the flex cable went to, previously). I know it's not a nice solution. But it works, eliminates one possible fault source. Hopefully I won't have to get it apart anymore. Result: all the same, unfortunately. :roll:
DSC_2992_.JPG
Did another research and found out about the (in)famous Bitron 1929SJ (or speedo interface box, another name for it) which clearly is fitted into my car and when I found it (easily), I immediately noticed it had been opened before! Less work for me :lol: as I didn't have to undo the glue. Opened it and it still had the paint on it, so I bathed it in Acetone and used a tooth brush - when solder pads were blank, I started to test it. Measured all and every passive components and also the transistors and ICs. All measured fin. Decided to fully resolder all and every solder joint. Took half an hour. Put it all back together and went for a test drive - speedo working perfectly, hasn't failed yet! Normally it would fail at least once here and then, has started with this since a week or so. So, I think I nailed the speedo going to zero problem, without any need to spend money to buy a new Bitron :cheesy:
DSC_2993_.JPG
(That's how it looked when I took it out of the car. Forgot to take a pic of the PCB, duh...)

Rev counter problem is the same, though. I consulted the electric schemes in Haynes manual, it doesn't go through the Bitron, it comes direcly from the main ECU in motor. I can't find out if it uses the TDC sensor or something else to figure out the speed. As this car has some modifications (Bosch pump, for example), it might very well be a problem of missing signal? I don't know if that's possible. I've read many cars get RPM from alternator. Maybe it's still the instrument cluster, after all, as I got the point to stick to 4000 rpm suddenly and it stayed there, after knocking around hardly on the instruments cluster. After turning off ignition, it fell immediately to zero and wouldn't go alive again, not even knocking. So, maybe I knocked excessively and brought the meter off its balance? I mean, if it doesn't get a correct signal, maybe it can be made to move by a hard knock and stick somewhere else, like it sticks at zero. I don't know how these meters work, they are different from the simple meters used for temperature and fuel, they have four pins. So, this doesn't necessarily mean that the problem lies in instrument cluster. It might well be a wire or a missing tachometer signal. Right now I don't have time to fiddle anymore with this, will move this to future problems to solve. Priorities right now are ignition switch and air conditioning.
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