Smoking Gauges?

[Tonker1]

I was working on my wiring a week or so ago and smoke started coming out of the region marked by red in the image.

At the time, the hazards were on and the earth cable for the gauges came off and next thing I now the high beam lights are blinking like hazards. By the time I had flicked the battery kill switch and had the gauges out of there temporary position to take a look, the smoking had stopped.

With the gauge case earthed again, the high beams stopped blinking and there was no more smoking. With the gauge case de-earthed again the high beams would start flashing and no more smoke would appear.

The fuel level and water temp gauges still work. The oil pressure gauge has never worked and the ammeter is not wired

Has anyone had there gauges smoke before?

Do the voltage limiter boxes need replacing?

Thanks in advance

[72ls5fla]

the only gauge I have seen smoke before is the ammeter.

and it usually is followed by a bad fire........

I would take each out and have a restorer check them out.

my 2 cents..

[dodj]

I would first remove the voltage limiter and see if it is pulsing 12vdc on and off. I suspect it may be stuck on, delivering 12vdc all the time.

[Tonker1]

For testing, do you know which terminal is which?

[dodj]

Case is ground, single spade- pulsed output, double spade, 12vdc input.(edit - i didn't write what I was thinking)

Lights blinking is a circuit grounding issue. Make sure you have properly grounded your switch panel.
Gauge problem is very possibly related to the grounding. Electricity does strange things when it has to find it's own path back to -ve

[anlauto]

Scary....Where there's smoke...there's fire

[HP_Cuda]

Where exactly in your pic is the earth ground?

I'd say it's probably the ammeter as the culprit but as usual you narrow it down little by little.

[anlauto]

Where exactly in your pic is the earth ground?

He's standing on it taking the picture....duh  

Just kidding

[ChallengerHK]

The ammeters tend to be problematic, both because of age and because they were a bad design to begin with. By definition, all the power in the car runs through the ammeter.

Somewhere on here there are instructions for converting it to a voltmeter. You can also buy a voltmeter from Redline Gauge Works.

[HP_Cuda]

Happy New Years my Canadian friend!
 



 

He's standing on it taking the picture....duh  

Just kidding

[anlauto]

 

[Tonker1]

Where exactly in your pic is the earth ground?

I'd say it's probably the ammeter as the culprit but as usual you narrow it down little by little.

The ammeter has never been wired while I have owned the vehicle and the ground cable was attached to one screw holes in the gauge case. I removed it to get the guages out of the car and inspect them.

Case is ground, single spade-12vdc input, double spade, pulsed output.

Lights blinking is a circuit grounding issue. Make sure you have properly grounded your switch panel.
Gauge problem is very possibly related to the grounding. Electricity does strange things when it has to find it's own path back to -ve

I just checked the voltage limiter with both analogue and digital multimeters, the voltage is permanently 12vdc on.
The fuel gauge works, as does the temperature gauge. The other two gauges aren't wired.

Is it a problem that the voltage limiter is stuck on 12vdc on?

This is the first time that I have ever had the fuel level gauge wired to the sender. Luckily the sender is out of the tank so I've tested the gauge for accuracy and it is pretty spot on. The fuel level gauge arm creeps slowly in small increments. I took a video of the movement, I don't know if it is operating normally or if it is a sign of some other issue. Sorry for the glare and low quality audio.

http://i1161.photobucket.com/albums/q514/Tonker1/FuelLevelGauge_zps7b9884d1.mp4

Thanks in advance

[Jesus H Chrysler]

When you lost the ground, the power found the next easiest path.  Unfortunately that sometimes takes it places you don't want it to go and it fries things along the way.  For example, maybe a circuit that was meant to take only 1 amp to run a gauge is now back feeding the headlights to the tune of 10 amps.  Now the wire and circuit board runners that were rated for 1 amp become heated and start smoking.  They may not immediately burn up, but now they're weaker and more prone to catching fire in the future. 

Before putting power back to it again I'd check the board, wires and gauges for signs of burning or melting.  You'd hate to lose a Rallye cluster or even your whole car for a simple wiring problem.  Check for yellow, brown or black marks on the board, wiring and gauge interiors.  Sniff around and see if you smell burnt plastic or anything out of the ordinary.  It's better to repair or replace anything now, than let it ride and have gremlins in the future.

[73EStroker]

Actually folks there is basically nothing wrong with these ammeters. They are after all 40+ years old and require maintenance. What happens is the fibre insulators dry out and shrink. When that happens the terminals become loose inside the gauge. If the gauge is not damaged then you simply undo the nuts holding the large wires on and firmly retighten the lower nuts to make good contact thru the gauge internals. Then reinstall the wires. I did this and zero issues. What has to be done though is drill 3/16" holes straight through the firewall block and run wires to ammeter direct instead of thru terminals.
Sorry for hijacking the thread but ammeters get a bad rap.

Tinker I would say you got 12v direct thru the 3 other gauges. If this is the case then you will have to rebuild and get a new electronic 12-5v converter limiter.

[MEK-Dangerfield]

Tonker I would say you got 12v direct thru the 3 other gauges. If this is the case then you will have to rebuild and get a new electronic 12-5v converter limiter.

That's where I'm confused. The Voltage limiter puts out a pulsed 5 volts, so the only way to measure it is with an analog meter. If 12 volts did indeed go through all 3 gauges, then he got off lucky in that only one of them fried.

Just for kicks, with an ohm meter set on the lowest scale, see if the daisy-chain black wire that ties all three gauges to the voltage limiter has continuity all the way around. Maybe the wire feeding the oil pressure gauge has a disconnect in it?