Garth S

[see post #10 for solution found ~3 weeks later to the issue introduced below]

My central alarm "!" and its 'cancel' button on the console started flashing today; however, no pod indicator icon illuminated, nor would the cancel button terminate the '!'. The flashing was intermittant, and would spontaneously dissapear.
As this appeared to be a Class A alarm (cannot be cancelled by the console button as Class B alarms can), I quickly stopped to check things over. The strange thing is that no pod indicator accompanied the "!" to identify the alarm Oil pressure was strong, brakes good, brake fluid level OK ... leaving the 4th and last class A alarm as low oil level - which it was. I was letting it go, as an oil change is due ...
Problem solved, I thought - just add oil when I get home . So oil topped up, and did a check of all the pod indicators with engine off and key in the run position: they are all correctly lit - and will hilight when prompted by, for eg., pulling on the handbrake.

Took off for a test run: car running perfectly, but cresting a slight hill a mile later, the same unidentified, non cancellable alarm clicked in - this time, it was a regular 2-3 flash/sec - until it self cancelled.

Any ideas???

I'll whip it up on the hoist tomorrow, and pull the wire on the oil level gauge to check that out .... on the very faint thought that the float ball inside the sump may be stuck in the bottom position. Handbrake circuit appears OK: it is a non cancellable like a class A, but should not flash if shorted or left on.

The alarm system is trying to tell me something .... but it needs to try harder As far as all operating systems - everything appears to be running perfectly.

Mike Frye

When you first turn on the key do you have all warning bulbs testing OK?

I had a similar problem thinking they were all on, but one of the test bulbs for the lights wasn't working, so that's the one that started tripping, naturally.

I know this isn't the cause of the problem, but if one is out, more may be out and you won't have to guess next time. Check your owner's manual for which ones you have and where they are.

Garth S

Yeah, agree - first thing I checked too
.
Hummm - still a puzzle ...

the flyin' scotsman

Given that the oil level was low and the car is due for a service would it not be prudent to change oil/filter and reset the system assuming it has residual memory.

Class A alarms perhaps require full batt. disconnect.

SeanR

As Mike said, start by verifying that all of your warning lights on the dash actually work. Grab the owners manual and do a comparison.

For example, when I got my '88, I got that warning everytime I started the car, but nothing was lit. After doing the above, my ABS light was burnt out.

Start there and then move forward.

heinrich

Check all warning lights at first key turn as suggested!!

Garth S

H, my good fellow - I wish I had thought of that!

Seriuosly, this was done within seconds of the alarm first coming in - and ~ 10X since: every pod icon/message/red window/etc lights as designed.
On the basis of 'what happened last', my suspect is still the sump level indicator. This AM, instead of pulling its wire and checking both the pod alarm status and continuity on the sensor - I opted for a seismic event, in case the sump float arm was stuck; the sump was given a few love taps with a rubber mallet, followed by a brisk run in the country.

This was an excellent excuse to stop by the stable to watch my bride skillfully shoveling horse ****e, play with the new baby fille ( already 500#), watch several hundred Canada geese fly overhead honking away ... and picked a few fresh MacIntosh apples to share with the other horsies.

So far, this combined therapy appears to have worked - no alarms came in and I feel refreshed: I will repeat the sequence tomorrow.

Malcolm - an '80 is barely beyond stone age technology: it doesn't have the memory capacity of an advanced alzheimer's patient. .... but I will pull the plug on it if the alarm rings in again.

the flyin' scotsman

Shovelling horse ****e does take one to other places.

Good to know the tried and true 'bash with a hammer' still works.

Mike Frye

Garth,

Sorry, I missed the part in your initial post where you verified that the warning lights all test OK. I still think you have an indicator circuit issue that you should be able to diagnose by pulling the sensor wire and cranking it up.

I don't think there's any case where the (!) light should come on without any other light.

Garth S

So, back 3 weeks later with the same issue - the randomly flashing pair of '!''s reappeared several days ago, with no other icon lit .... and they all work correctly!
That was conforting in a perverse way, for the oil level indicator deal discussed above was like whistling to keep elephants at bay - it worked, but lacked reason: besides, when I changed oil, I started up intentionally 2 liters shy of full - and the alarm and icon came in as designed .... so proved that I had solved nothing.

What I did notice when after being slightly airborn on a 'test drive', the !'s were more intense when kissing the road again .... and this time, the voltmeter shot up to ~15v ..... Ah ha!!!
When home, battery voltage was indicating a normal 12.5V, and the alternator put out a normal 14v ...... however, when I twisted the throttle up to ~3500rpm, the alternator pooped out ~16v
Overcharging is an indicator of either a crashed regulator, a high resistance in the primary ground loop ( ground strap engine to chassis or battery to chassis .... or a shorting plate in the battery.
As the battery voltage was normal, I obviously .... and stupidly ... pulled the alternator and replaced the regulator and brush holder: started up, promptly repeated the overcharge deal! Thinking then that it was a ground issue, I did voltage drop measurements on the major ground straps .... nada. ( BTW, resistance tests tell you nothing useful in this type of search, so don't waste your time if facing this)

What should have been obvious was the thing I tested last - however, as the battery read 12.5v, it appear OK - and fooled the sox off me. In reality, it carried what is known as a surface charge .... but had an (intermittant?) dead short in one cell. Despite this, it still started the car easily .... completing the deception. However, when the plates shorted, the alternator overcharges heavily in an effort to restore the battery .... and coincidentally, drove the central informer/alarm module beserk.

New battery - no overcharge, no ! lights flashing.

Moral of this shaggy dog story .....

A system overvoltage in the 16v cars can drive the class A warning lights to bleep randomly, with no class A alarm.

the flyin' scotsman

The diagnostic techniques for this thread are truly out there. First the hammer job on the sensors then gettin' her off terra firma for the warning alarm.

Excellent work Garth...........glad you've still got dry pavement for such adventures.

BTW..........as the one cell plate is shorted would a hydrometer test not have revealed the problem or are they closed cells?

Alan

Garth good job on the detective work - a couple of points.

1) I suspect its supposed to do this deliberately - since overvoltage is dangerous for the cars electronics and the battery. Not sure if there should be any other warning for this - that does seem odd.

2) Your exact proposed cause for the battery failure doesn't make sense to me. I'd suspect instead an intermittent open circuit inside (or outside) the battery based on bumps & stress...

When a battery cell shorts it will usually cause the alternator voltage to fall not rise. Classic causes of high alternator outputs are failed regulators (you changed already) and open circuit or load impaired (usually won't still start the car) battery.

The alternator is less smart than most folks think.

It has no idea if its charging a battery or not...or how much charge the battery needs - it just tries to achieve its set voltage output.

If its working right it will have a steady state voltage that is lower with additional load and higher with lighter load. There are temperature & rpm effects and it relies on a fully functional battery as a kind of ballast to work correctly.

Instantaneous output (spikes) may be the result of additional load switching and intermittent events - but steady state average conditions should not... so if the guage accurately read 15v given what else you have checked its likely that at that moment your battery was not connected correctly.

Seems it was inside the battery anyway so great you found it... this could have been a nagging issue for a good while till it became much more obvious...

Alan

Garth S

Alan,
Actually, the first test on the battery did indicate an open cell .... so you are correct; however, we then 'bounced' the battery and repeated the test .... and it indicated a short.
Suffice it to say that something was flopping around inside - so it was replaced.
Maybe the saga continues, for I did the voltage measures again this AM - and voltages in excess of 14.5 were recorded. Not to risk the new battery, I pulled the alternator for a trip to the load tester ( friend's shop). The output was normal at idle and at full load, giving ~90amps @ 14.5v; however, at modest load, it produced 15.5 - 16v @ 20 amps ... so we suspect an intermittant problem with the rotor ( brushes & stator rings are OK): this is looking more like a root cause - and beyond what I can DIY.
The rotor will be removed and tested - or replaced ( Paris-Rhone type) - so will know tomorrow.

Mrmerlin

Garth what ever happened to the overcharging alternator???

Garth S

Stan, glad you jogged my memory : this was a real 'Sherlock' deal .... and became the following "shaggy dog" tale .....

To back up a bit, the original Paris-Rhone quit the year before .... and I took it to an alt. shop bench tester for diagnosis: what it turned out to be was some mice had made a winter home in the cooling duct - and in spring, some of their crap ( literally) was inhaled by the alt and jammed the brushes from contacting the slip rings ..... so the shop pulled it apart and blew it clear. Alt then worked perfectly ....

That should have been the end of the story - until the above episode started! During that deal ( back in '07), the overcharge also had an AC signature on top of the DC output - which took me too long to figure out.
When I pulled the alt for the Nth time, I went all the way on dissasembly: what I found was that one of the long case through bolts had trapped and abraded one of the 6 field coil wires going to the 3 sets of 2 plate diodes: this must hade happened in the year before when they ( hastely) put my alt back together.

The net effect was that one of the 3 field coils was shorting to ground ( intermittantly ??) , so the car was seeing part of a 3-phase AC generator where it should see pure rectified ~14V DC. While the battery had a bad/weak cell at that time, the shorting field coil was the culprit responsible for driving the system nitz - cars don't like AC .

The perfect cure was building and installing the AL325X upgraded alternator - and all still works like a charm ....