project 1980 Austin Princess

[SiC]

Got a wiring diagram? Google doesn't bring up much.

[SiC]

I wonder if a bullet/crimp/etc is not making good electrical contact and high resistance. So when left powered for long enough, it is slowly heating up and eventually getting hot enough to start melting stuff.

 

You don't happen to know someone with a FLIR or similar IR heat camera? If not, an IR thermometer you can wave around under there.

[Zelandeth]

I assume the fusing on this is similarly simplistic as on the early Metros, as such pinpointing the source without major disassembly is going to be hard.

 

If the dash has already been out, the favourite has to be the chances of part of the loom getting crushed when it was put back in place.

 

I'd probably pull the steering column cowl off first though just in case anything in there is to blame (is the headlight switch down there by your left knee like the Metro?).

 

At least I'd hope that once things are apart this should be pretty easy to see with a careful inspection.

[vulgalour]

Been rolling this around in my head to try and narrow things down before dismantling.

 

- ignition off, battery disconnected: all systems dead, as they should be.

- ignition off, battery connected: no hot electric smell, clock and interior light work, etc. as normal

- ignition on, engine not running: no hot electric smell (or it's taking much longer), interior light, clock, lights, radio, etc. all work as normal.

- ignition on, engine running: hot electric smell after about 1 minute, getting stronger the longer it's on.

 

NB:  Indicator flasher disconnected for all of the above.  Once connected, it continually clicks rapidly as soon as ignition is on.  Clicks at normal rate if indicators are engaged.

 

No change in how quickly the smell appears or gets stronger no matter what systems are on - heated rear screen, main beam, fan blowers, etc. - and all systems operate as normal.  Nothing in the engine bay is getting hot, doesn't appear to be earthing through the throttle or choke cable, for example.

 

Working theory (as supported in posts above) is a loose connection on the back of the dash, even though all of this has been perfectly fine the last time the car was used.  Only way to find that is to remove the dashboard which thankfully isn't difficult, just annoying because of how often it's had to be done this year.

 

The smell is very specifically hot electrics too, that slightly metallic ozone-y smell you get when something is overheating, but not the smell you get from dusty components warming up or Scalextric controllers.  It's definitely inside the car too and is surprisingly localised, you can only smell it from the driver's seat and it appears to be behind the instrument cluster rather than the ignition barrel or steering column.

[Noel Tidybeard]

next disconnect the column stalks and try again- disassemble indicator stalk and clean tracks- my 106 did something fairly similar which was alarming on a less than 3yo car!

[SiC]

next disconnect the column stalks and try again- disassemble indicator stalk and clean tracks- my 106 did something fairly similar which was alarming on a less than 3yo car!

^^ this.

 

Indicator flasher (if 2 pin unit) shouldn't be working away with ignition on, as it shouldn't have power. I'd disconnect that first and see if the smell goes.

[vulgalour]

I have disconnected the flasher, as described above, the smell persists.  Anyway, I'll report in full when I've had chance to pull the dash.

[SiC]

With it disconnected, it doesn't mean that power isn't going the wrong way through the indicator switch though still.

[MikeKnight]

The crimped connectors on the back of the current dash were always meant to just be a prototype, to see if my spaghetti inspired wiring actually worked and we could do away with the horrible printed PCB.

 

And it did!

 

I need to remove them all and solder the connections properly now. One of them has probably popped out and is grounding out. Those blue crimps I use for prototyping are absolute crap.

[vulgalour]

Probably the ammeter connections or something near them rather than indicators, I'd've thought.

[scaryoldcortina]

Instrument voltage stabilizer.

 

It's the only thing I can think of in that vicinity that might cause issues only when the car is charging.

 

Also, might be a symptom of overcharging - what's the battery voltage with the engine running?

[SiC]

Instrument voltage stabilizer.

 

It's the only thing I can think of in that vicinity that might cause issues only when the car is charging.

 

Also, might be a symptom of overcharging - what's the battery voltage with the engine running?

I was pondering that one too. However it should be still running away even with the engine not running. At least if it's anything like the MGB one where it tries to put out 10v. Could also be a "solid state" one where the voltage regulator has taken a bit of a dump.

 

My thought/suspicion is that it could be a contact miss aligned or the grease has built up gunk over time and has become partially conductive in the indicator switch.

 

The indicator flasher shouldn't be working away with the indicators off. Power must have been getting to it somehow.

[scaryoldcortina]

Backfeeding through the dead voltage stabilizer?

[vulgalour]

I do have a spare voltage stabiliser of unknown quantity. However, if that had failed it would have taken my fuel gauge and temperature gauge out and those are both working fine.  That is providing I'm thinking of the same component, a metal block on the back of the instrument cluster that is a push fit.

[BeEP]

next disconnect the column stalks and try again- disassemble indicator stalk and clean tracks- my 106 did something fairly similar which was alarming on a less than 3yo car!

 

My vote would be indicator switch tracking as well, and it's a quick thing to check before dismantling the dash.  Craig the Princess, Mrs CtP and myself had a similar experience in an Allegro (which has similar switches) on an Austrian motorway; smoke emanating from the steering column.  When taken apart it was apparent a groove had worn/burnt in the plastic via which the switch was shorting.  As an indicator switch was one spare we hadn't taken the groove was filled with superglue and a fun few hours spent fending off wasps waiting for it to dry.  No more problems during the trip and as far as I know the switch has never subsequently been replaced.  If this is the problem and you do take the switch apart, make sure you keep your eyes on where the little springs end up; they're bound to ping off somewhere!

[SiC]

Backfeeding through the dead voltage stabilizer?

Plausible. But I'd thought that flasher shouldn't have a current return path with no indicators selected? Hence thoughts on that switch.

[SiC]

The wiring diagram for the MGB, but as Lucas it's likely similar. There are only so many ways you can wire a flasher.

 

I can't see how the flasher can have power through it, which it must be if it clicking when attached, with indicator switch set to off position. Also if the voltage stabilizer if duff, then I can't see how that's making the flasher clicking either.

[vulgalour]

The replacement flasher is a two pin with a separate earth wire.  The earth is good, or at least as good as it ever gets on this car, and cannot be improved.  Thing is, I still don't think it's related to that because the problem is there with it disconnected.  I think the flasher clicking is a something of a red herring.

[SiC]

It'll have to be a divide and conquer exercise. Disconnect sections and then reattach bits as you go, seeing/smelling what happens.

 

Do you have a clamp meter to measure the current draw on circuit sections?

[vulgalour]

I'm not sure, I think we do.  It'll end up being something simple and yet obscure, like the last issue with the dash where it was the cigar lighter shorting out (since replaced with new).

[JeeExEll]

Hazard light switch?

[vulgalour]

Is operating fine.

 

Fell at the first hurdle today.  Need to get the steering wheel off to get the indicator stalk off and for that I need a big adjustable spanner or a 33mm socket, neither of which I can find.  Must have one or the other because I've done the wheel before.  On the plus side, there's no signs of anything getting hot inside the column shroud.

 

I don't think there's any point stabbing in the dark on this one until I've got stuff apart and had a look.  I only have about half an hour a day spare for car time at the most, so this is going to take a while.

[purplebargeken]

I had a 1989 Ford Escort. It smoked profusely from behind the dash one day. I simply opened the window.

 

I guess that wasn't entirely helpful.

[Christine]

It's fixed .I saw it in news 24..   Joyful,  harmonious,  relationship resumed  

[vulgalour]

It's not fixed, the problem is merely isolated.

 

The first thing I did today was unfasten the steering column cowling and have a look at the wiring.  Nothing amiss, all nice and clean and no signs of damage.  I then went to remove the steering wheel only to find I didn't have a 33mm socket at home.  Went to the unit and got the only thing I could find that would match, an adjustable spanner, which when I got home I found didn't go big enough.  Had to do some work so next break I got I went and tried to buy a new socket, eventually ended up at Halfords as it was the only place with one on the shelf.

20170920-01 by Angyl Roper, on Flickr

 

 

That sorted it was easy enough to get the steering wheel off so I could then remove the stalks.  Merely loosen the column clamp screw, unplug the two stalk connectors on the loom and remove the stalks.  Steering wheel could then go back on so the car is still mobile.  Fired it up again and waited for the smell of burning electricals which after several minutes did not manifest.  I plugged the indicator flasher in and that remained silent, though that could be because the circuit is incomplete without the stalks, I don't know, I'm not an electrician.

20170920-02 by Angyl Roper, on Flickr

 

20170920-03 by Angyl Roper, on Flickr

 

On inspection, there's no sign of anything having become warm, let alone hot enough to deform.  Several people had already suggested it could be worn or damaged tracks inside the switch so that would have to be the next step.

20170920-04 by Angyl Roper, on Flickr

 

Difficult to photograph, but once inside the switch there's no wear beyond what you'd normally expect.  The grease hasn't dried out, there's no dirt to speak of.  All of the plastic pieces are as new.  There is nothing untoward inside either switch.

20170920-05 by Angyl Roper, on Flickr

 

20170920-06 by Angyl Roper, on Flickr

 

I cleaned the contact surfaces anyway, since it was all apart, and then reassembled.  Then found that the indicator solid was locked solid so took it apart again.  Then fought with the return springs, plastic locators, hub ring, backing plate and stalk to line it all up, screwed it together, and the indicator stalk was locked solid again.  I tried several different combinations and alignments of the various internal components always with the same result: massive frustration and a locked up indicator stalk.  I can't find a diagram to show alignments, etc. of the switch internals in the manual, nor pictures online.  I don't have a reference picture myself because on opening the switch up everything moved before I even lifted the backing plate off.

 

That means in trying to fix this, I've actually made things worse.  Perfect.

 

Next step is once I've actually managed to get the switch to go together properly - which it probably will after I've had a good rest and more than five minutes spare to work on it - is to plug it back in and see what happens.  If the burning smell and smoke don't reappear than brilliant, I've fixed it.  If it does reappear and it is the switch pack I have no idea how to fix something that doesn't show any signs of being broken.

 

Time will tell.  But it's certainly not fixed.  Quite the opposite, in fact.

 

[PhilA]

Relay has silenced because it is on the battery side of the switch, the bulbs being on the opposite. Would suggest something amiss with the switch, particularly if the thing was clicking but not making the bulbs light up. Suggests a short to ground in the switch or switch loom that you removed. Smoke there would be expected because instead of having the resistance of the bulbs to stem the flow of electricity it'll be able to flow unhindered and make things get very hot.

 

That may also be the drain you were experiencing a while back, hazard circuit feeding back through the switch, which has since gotten worse.

 

Might be something as simple as a piece of the spring or something else intermittently touching something attached to the column.

 

Might seem worse but it's definitely a step in the right direction because the problem is now looking to not be in the wiring before the switch.

 

Phil

[vulgalour]

With the smoke I got I'd expect at least some deformation of plastic somewhere and there's nothing, it's all lovely and pristine.  No corrosion or discolouration of any metal components, no damage such as chafing, splits or perishing on the wire coatings, no damage to the plugs or pins, no excessive (or really much of any) wear to contacts.  It all looks like a brand new switch inside and out.  The wires are still nice and flexible, the solder joints free of cracks (unless they're microscopic, obviously) and it does look like anything has been caught in trim or similar allowing it to short out on a metal part somewhere.

 

The plan at the moment is to get the stalk switches back together if we can, reattach to the car and see what happens.  If the act of taking it apart and putting it together cured things then that's great.  If not then I've not idea.

 

The dashboard will still need to come out because I'm having problems yet again with the illumination of the main beam telltale and the right hand instrument cluster.  I have no idea why because Mike has run through everything and it all checks out right up until you actually put everything together in the car.

 

I absolutely despise electrics because they make me feel utterly helpless.  I try very, very hard to understand what's going on but it doesn't go in, much like maths, just seems my brain isn't very good with those sorts of things.  Every time I think I just about understand something with electrics and I'm asked to explain it back to check, I always get it wrong and always on something really stupid.  It just doesn't make any sense to me.

[purplebargeken]

You have my utter sympathy, electrics are a complete mystery to me and likely will remain so.

 

Good luck with the stalk.

[SiC]

With the smoke I got I'd expect at least some deformation of plastic somewhere and there's nothing, it's all lovely and pristine.

My thoughts on that is it might have been some grease that has burnt off from something hot enough to burn it but not hot enough to damage the plastic. Which is why there has been smoke once but not again.

 

Just only a theory though from what you've said on here.

 

The wires are still nice and flexible, the solder joints free of cracks (unless they're microscopic, obviously) and it does look like anything has been caught in trim or similar allowing it to short out on a metal part somewhere.

 

Still quite possibly could be. A multimeter on resistance/continuity mode and probing the stalk socket on the car side would tell a lot too if there is a short.

 

The plan at the moment is to get the stalk switches back together if we can, reattach to the car and see what happens. If the act of taking it apart and putting it together cured things then that's great. If not then I've not idea.

 

Just remember that they got this together originally in the factory, so it must be possible to reassemble it again.

 

Take it home, sit at the dining room table/desk/etc and take time. Don't force it if it's not moving. Pretty much every switch I've taken apart has been a pain to put together again. Usually the springs are always trying to escape and become misaligned when reassembling, jamming it.

 

 

I absolutely despise electrics because they make me feel utterly helpless. I try very, very hard to understand what's going on but it doesn't go in, much like maths, just seems my brain isn't very good with those sorts of things. Every time I think I just about understand something with electrics and I'm asked to explain it back to check, I always get it wrong and always on something really stupid. It just doesn't make any sense to me.

To be fair, I think in this case I think there maybe a bit more going on here than just electrics.

[Exiled_Tat_Gatherer]

Good luck with it V - I'm also a complete idiot when it comes to electrics. My (electrician!) father gave up on me years back! Luckily I haven't had a smoke signal in the car as of yet..... but I have to redo the SPitfire and the GT6 racer (from scratch that one) in thenear future and I'm dreading it!

 

Can only say - may the force be with you