406 2.1td - Engine shuts off during driving, then can be started normal

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joydivision
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406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

My 406 2.1td has done this twice, have done 1000 km with the car since I bought it and this started yesterday. It shuts off during driving, but only now and then, after you can crank and start it right away and works fine. The first time I was a little scared and didn't look well at everything, I thought it would be lack of fuel, as I was close to reserve (light was on), but then I filled tank and today it's done it again. 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, but I suspect it will :( . 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. Thanks in advance for any hints on this.

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GiveMeABreak
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by GiveMeABreak »

The only time I've had the engine cut out and all the electrics on the dash, instrument panel and everything go off was on a motorway on my Citroen C5 MK I 2.0 HDi. It happened twice. After pulling over and restarting - all back to normal. In my case it was the Switch control module under the steering wheel - had the whole thing replaced and it never happened again.

I'm not suggesting this is the same in your case, but something to consider.

joydivision
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

Thanks for your suggestion. I don't think that's what is happening here, as the instruments and electrics remain normal, it's like if you turn the key to switch motor off and go to accessories position, just that it's not the case...

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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by Dormouse »

Does the ignition key or barrel have any sloppiness/feel of wear? even a fairly small amount.

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white exec
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by white exec »

On XM (with the same engine) the culprit can be engine bay fuse No.1, which supplies the double ('Bitron') relay enabling injection. The fuse may not actually blow, but can acquire poor contact, caused by an adjacent one (for the blower and A/C) getting hot. May/may not be the similar on 406. Symptom: engine cuts, but all else stays live.

joydivision
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

Dormouse wrote:
10 Jul 2021, 15:44
Does the ignition key or barrel have any sloppiness/feel of wear? even a fairly small amount.
Yes, it sure does, I just tested - it even allows for intermediate positions if you turn the key very slowly, where no lights are on at all, seems really very worn out. I could try to give it a good treat with deoxit spray first, but I suppose it needs replacing, as I'm also pretty sure the contacts for the blower motor are burnt out (as someone fixed it by pulling a different cable as +12V for the blower - I know this as I've recently fixed the blower, wasn't working with speed control, was wrongly wired). I haven't looked up the price for a new ignition barrel switch, but if it's not expensive, I think I'll change it. Anyone knows if changing it is difficult? I've got Haynes manual (procedure is explained, but kind of confusing and photos aren't great), but I think there are good videos on Youtube, remember coming across one.
white exec wrote:
10 Jul 2021, 16:10
On XM (with the same engine) the culprit can be engine bay fuse No.1, which supplies the double ('Bitron') relay enabling injection. The fuse may not actually blow, but can acquire poor contact, caused by an adjacent one (for the blower and A/C) getting hot. May/may not be the similar on 406. Symptom: engine cuts, but all else stays live.
You might be totally spot on with this! I'm saying it because of two reasons: although the engine ends up stalling (electrics staying alive), it's not immediate, it starts by loosing a lot of power (that's why I though it was out of fuel yesterday), then only a couple of seconds later it ends up stalling and you notice the steering gone stiff as it lost assistance. The other reason is that I recently fixed the blower motor (means that it is now being used regularly, while before it was almost never used, it ran only on high speed), so might happen exactly what you're saying, provided it's the same arrangement as in the XM, I will check this. Might also be only a corroded fuse, this car does have some electrical problems and some heavily oxidised electrical connections, I still have to find some time to give a good treat with deoxit spray to all push on connectors and electric connections I can reach...
I've been thinking: I guess the fact that the engine doesn't stall immediately means that I can rule out a problematic stop solenoid, right? As it would make the engine stall immediately or not allow it to start from time to time (not the case at all).

joydivision
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

Checked the fuse - it's fine, also checked ALL other fuses and applied deoxit to all contacts. All fine, and all fuses have correct rating... So I bet it must be the ignition switch then.

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moizeau
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by moizeau »

I'd put money on it being the ignition switch especially as the blower track hs been damaged. I had one that got so hot it melted the internals and I couldn't turn the key. They are straight forward to fit put I remember the steering lock bit is a pain. I changed mine and left that bit off. While your in there, take the blower live from the ignition switch and run it to power a relay which is supplied via a fused 12v supply (that you already have). This issue was also a problem on Xantias if I remember correctly. Somewhere on here will be a post with the relay mod (under Xantia).

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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by Dormouse »

remember, the switch and the lock are really two separate pieces and both might have their own faults even though they are joined together.

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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by admiral51 »

How many keys do you have on the ignition key that you use on a daily basis ?
If you have house keys etc on the fob have you tried it without them and just the ignition key ?
Just thinking out loud lol

Colin

joydivision
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

Moizeau: yes, makes sense. Thanks for the details. I think I'm going to pass on the relay mod, though, as the blower is working fine after my repair - it had been repaired previously, having been wired to another 12V feed which seems to support reasonable current (I'm already avoiding to run blower at max, anyways), so I think I'll just leave it like this. Tomorrow I'm getting a new ignition switch. Let's see where I can get it for a good price. If not, I'll have to order one from EBay.

Dormouse: I know... but the lock itself, although kind of worn, seems to work just fine.

Admiral51: there are a couple of keys, yes, but I haven't had any problems starting the car. I mean, if they would interfere with the transponder protection thing, then it would also sometimes refuse to start, right? That's what you're thinking, right?

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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by Dormouse »

magic

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white exec
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by white exec »

I know this is a potty suggestion, but it has been known for a right knee to knock into a dangling IGN key bunch or fob while driving, thus cutting the engine. Of course it re-starts normally afterwards...
How do I know this? #-o

joydivision
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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by joydivision »

Sure, sounds perfectly possible. But I'm pretty convinced it didn't happen, at least the second time it happened. The first, all is like a blurr, as I was a little scared (or at least, surprised), the second time I was already mentally prepared for the possibility, so I remember almost all details. But what can I know. It's possible. Again, would speak for a worn ignition switch. I have to see if I can reproduce it while engine is running and car stationary, wiggling a bit at the key or key bunch, I tried a bit the other day but wasn't comprehensive enough.

Anyways, tried today but didn't have any luck at local dealers, it's too old... I'll have to get it from EBay or maybe here in Portugal from classifieds site, I've seen some. Problem: I don't know the part number or the exact appearance of the connectors - I know the one for the '99 onwards is different, that I know for sure, have seen on EBay. But even the one before, which appears to be the right platform, I'm not sure If there are differences between petrol and diesel models, I mean, I'm not sure if several versions existed... Does anyone have any hints about this or do I have to dismantle the covers and try to get a look at the wiring? Right now I'm using the car almost daily, it's not very practical to do it, but I'd like to sort this quickly (although it hasn't ever done it again...), but I obviously don't want to buy a wrong switch, either.

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Re: 406 2.1td - Engine shuts off during driving, then can be started normal

Post by admiral51 »

Sorry for the late reply Joy but my thinking is that with extra weight on the key fob with extra keys etc then a small amount of swing maybe enough to turn the key in the ignition barrel towards the off position particularly if the barrel is worn.
It will start up again no issue as you would be holding the main key and not allowing any movement except applied by you.
It may depend on how tight the extra keys are held to the ignition key etc but just thinking out loud and if it is on its original barrel its done well :)

Only going on your post about the fact that you could get the battery light on and nothing else by turning the key slightly and not getting the other normal lamps on.

Colin