project 1980 Austin Princess

[richardthestag]

not liking nerves ^^ bit but glwt MOT

[panhard65]

Oh good, there's the pre-MoT nerves I was missing!  Was beginning to think I'd got complacent and over-confident there.

What were you worrying about straight through with no advisories, well done !!!!!

[loserone]

Well done!

 

Hope you got back before the rain kicked in, that was fuggin horrible even in a modern electrical appliance

[vulgalour]

MoT's are always a bit scary, especially when it's an older car and one that you've decided to rely on as a daily as I have with this one.  I couldn't really find anything amiss so I got in the car to set off in convoy with Mike only to find the dash-mounted cigarette lighter won't power the sat nav, which is a bit odd because it didn't have a problem before.  That meant convoying without knowing exactly where I was going and Mike not realising that his fuel injected straight six turbo Supra has just a little better acceleration than my carburettered straight four Princess.  The drive out was a teensy bit stressful.  As was rediscovering Princess blind spots, made worse because I couldn't take the time I would normally for fear of losing where Mike was going.

 

We arrived without drama, happily, and the weird chuntery hunting thing the engine has been doing was still happening.  One look under the bonnet and Scaryoldcortina noticed that one of the spark plugs was loose!  I'd checked this several times and completely missed it, when I went to tighten it up it was only finger tight.  Glad we figured out what was causing the chuntering and resolved it before an errant spark plug could cause any damage.  Princess went through the MoT first and decided not to play nice with Scary and not let him have gears without a fight, behaved perfectly fine once I got in.  This car is a character like that.

20180329-01 by Angyl Roper, on Flickr

 

I assumed I'd missed something somewhere really obvious and while I did get a mild ribbing for the Arrowspeed (circa 1992) tyre that's on because the Camac (second hand from a Porsche, of all things) for that corner has a leaking rim, she went and passed with flying colours.  I was actually surprised at this, I had expected an advisory on something even though we've only done a couple of hundred miles since the last MoT because of breakages.

20180329-02 by Angyl Roper, on Flickr

 

So here's to another year of happy motoring, I hope!  On the drive home we did get caught in the sleet and rain, which was less than pleasant, and the whining speedo cable is pretty annoying at motorway speeds.  Oh, and the hazard switch celebrated the pass by now not working, so I need to fix that.  Clean sheet though!  I'm really happy about that, it makes all the hard work feel like it's been rewarded properly.

 

Just had a flash of inspiration and looked in the fuse box. I reckon I've found my issue with the non-operational hazards and cigarette lighter.

20180329-03 by Angyl Roper, on Flickr

[danthecapriman]

Sweet! A richly deserved pass that too.

[captain_70s]

Excellent stuff! Planning on painting it this summer?

[vulgalour]

There's already paint on it, why apply more?

[captain_70s]

There's already paint on it, why apply more?

Thicker paint = Stronger car.

 

Obviously.

[vulgalour]

That's the sort of logic one expects of a Triumph owner.  Everyone knows the key to a stronger car is pop-rivetted road signs.

[tooSavvy]

This thread.....

 

"Will it do The TON, Missta?"

 

 

TS

[mrbenn]

Congrats on the MOT, Vulg!

[vulgalour]

This thread.....

 

"Will it do The TON, Missta?"

 

 

TS

Book top speed for this car is 97mph. So sadly not

[vulgalour]

The issue is what caused the fuse to blow. Have you found that?

I have not yet. It could be the wiring for the rear cigarette lighter. It could be related to when the throttle cable was being an earth which weakened the fuse. It could just be a rubbish fuse First port of call will be to fit a new fuse and see if it does it again. If it doesn't, then check the things it powers are working as they should. Then, well, we'll just have to see I suppose.

[purplebargeken]

A new MOT is a wonderful thing. Well done to you all (car included).

[dozeydustman]

Well done Vulg. Having followed this thread from start to finish over the last couple of months since joining I'm sure Princess will give you many more years of motoring pleasure.

[320touring]

That's the sort of logic one expects of a Ballade owner. Everyone knows the key to a stronger car is pop-rivetted road signs.

EFA

[PhilA]

Book top speed for this car is 97mph. So sadly not

Congratulations on MoT.

 

It's evident you've improved the aerodynamics so it'll likely run the ton now.

 

Phil

[vulgalour]

Fuse #5 (16A) - non-ignition accessories

Powers (as far as I can work out): cigarette lighter (front and rear), interior light, hazards

 

Problem:  too much power going through this circuit is blowing the fuse.

 

Investigation:  I've checked for loose wires, bare wires and errant connectors.  Everything is present and correct.  I've disconnected the items listed in Powers to eliminate them from the system.  Fuse sparks when fitting, will blow if fitted.

 

Conclusion: Earth problem?   It's a bit strange really, I can't see anything that's changed to cause the problem and I can't find anything that looks faulty so I'm not sure what to do next.

 

Everything else works on the car exactly as it should, it's just this one circuit.  Any ideas?

[vulgalour]

Friend suggested it could be the clock, which also runs with the ignition off.  Disconnecting that makes no difference at all.  I have a sinking feeling that I'm going to have to pull the dashboard out again.

[Des]

 

Problem:  too much power going through this circuit is blowing the fuse.

 

Investigation:  I've checked for loose wires, bare wires and errant connectors.  Everything is present and correct.  I've disconnected the items listed in Powers to eliminate them from the system.  Fuse sparks when fitting, will blow if fitted.

 

Conclusion: Earth problem?   It's a bit strange really, I can't see anything that's changed to cause the problem and I can't find anything that looks faulty so I'm not sure what to do next.

 

Solution: Leave the fuse out.

 

You could try replacing the fuse with a strong bulb, how brightly it glows will give an idea of the current flowing, while it's there wriggle and poke at various auxiliaries see if you get a flicker. If you get stumped I reckon a flasher unit across the fuse holder might just give a nice pulsing magnetic field along the errant circuit that could be tracked with a compass, or by listening to clicks from a transistor radio like a geiger counter, all the way to the bastard self tapper that's intruding the loom somewhere.

[PhilA]

Does the fuse blow if you have the hazard switch engaged? Might have shorted to ground through the bulb inside it

 

Phil

[vulgalour]

it blows if it's engaged or not, connected or not. It's really odd and not the first time the car has done this and while I did think it was the dodgy cigarette lighter that we replaced, now I'm not so sure.

[PhilA]

Hmm, fair enough. Sounds like it's time to start tearing it apart again.

[vulgalour]

Great joy.

 

I've been having a think about this and I'm a bit perplexed by it.  Mike has suggested we have a look at the unit where there's more tools, later this week.  The only things not working are cigarette lighters, interior light and hazards, nothing else is affected.  I've no radio fitted at the moment so if I had one in, it may have taken that out too, I can fit a spare to find out.

 

What's really confusing me is with everything that it should power disconnected, something is still drawing power through that circuit.  If there was still all the bodge in the wiring I'd expect this, but we've cleaned it all up and everything should be good now.  The other annoying thing is that this circuit was working perfectly fine and I can't think of anything I've done or moved that might have disturbed or broken something.  The car was working fine so I basically left well alone when it came to the MoT.

 

The only trigger I can think of is the sat nav.  Back in 2012/3 I had two occasions I can recall of the same sat nav blowing the same fuse when it was plugged in. A new fuse on both occasions resolved the issue.  Later, in  2017, I found that the dashboard cigarette lighter was faulty when it turned out to be the cause of repeated fuse blowing and replacing it with a brand new one cured the issue, until now.  The wiring behind the cigarette lighter is quite cramped since it shares a tight space with the heater controls and the radio wiring so it's possible something back there is touching something it shouldn't and plugging a sat nav in is what's causing things to move about where they shouldn't.  In theory, whatever has moved somewhere it shouldn't hasn't moved back and that's the root cause of my fuse blowing issue.

 

Does that sound at all plausible?  It's all I've got to go on without pulling everything apart (which I really don't want to have to do AGAIN), I'm not really sure what else it could be.

[PhilA]

Yes

 

Been there done that with flexible plastic and cigarette lighter sockets.

 

Either that or the sellotape wrapped around the + wire for the not-fitted radio has fallen off and is resting against the back of something metal...?

[SiC]

I assume no crud hasn't fallen down inside the cigarette lighter socket?

[plasticvandan]

put a low ampage fuse in with the various items that run the circuit disconnected and plug each one in and see which one blows the fuse?

[vulgalour]

Phil:  I checked the tape on the radio wires and it's still present (masking tape, in this instance) and nothing is touching anything else.

 

SiC:  Not that I can see, unless something has fallen on the back and is bridging contacts.  It's horizontally mounted so tricky for stuff to fall in it.

 

PVD:  That's just it, with everything disconnected it still blows the fuse, and I'm not sure what can cause that.

[vulgalour]

It gets stranger.  Off out on errands today so heated rear screen, headlights, wipers and fan on out of necessity since it's tipping it down.  All is well until we're idling at traffic lights and the wipers start slowing down, check the gauges and sure enough the ammeter needle is falling.  Wipers off, it picks back up, wipers back on and it stays there.  I've been unable to replicate the escaping electricity problem.  I can't find any loose connections, dirty earths, damaged wires or similar so I'm really perplexed by this.  I even sat with the car at idle and as many electrical items on as I could and the escaping electricity issue did not remanifest.

 

I'm calling Old Car Stuff on it today because it self-healed and it's never been keen on very wet weather.  Conversely, it drove and ran quite nicely today, much more so than usual in wet weather.

[Squire_Dawson]

Even though it has an alternator these old ones can still struggle when you have a lot of electrical equipment in use, so I wouldn't worry too much about that. At idling speed the ammeter can show a discharge and as long as it charges once the car is moving all is well.