Central Warning Light comes on when accelerating

[mproseusa]

Does anyone have a idea why my Central Warning light on MY82 928 comes on when accelerating? No other individual warning light comes on with the Central Light. I can turn the light off by pressing the reset button, but the next time I accelerate, the light comes back on

[riber.bentsen]

Check your coolant level. Maybe it sloshes backwards as you accelerate, moving away from the censor?

Auto or manual gearbox?

[riber.bentsen]

Beautiful car btw!

[Anthony10370]

check your timing belt tension with a proper gauge, the extra forces of acceleration may tighten the pulling side of the belt just enough to slacken the tensioner side of the system causing the tensioner to send a "loose" signal to the central warning system.

[riber.bentsen]

Wouldn't the belt tension warning light come on as well then? But good call Anthony, that's probably it.

Do you have one of these:

[mproseusa]

Good suggestions guys. I'll check both the coolant level and the TB tension.
(I need to borrow the tool from tmpusfugit first ). Thanks.
Mike

[Landseer]

But the light wasn't added until 1985 -- there is no timing belt tension detector.

That said, if it were an 85-up car, that would be a good thought.

[mproseusa]

Thanks 'riber.bentsen'. I went out and checked the water tank and found that it was pretty low. I had a hard start / no start condition since May of this year. While trying various things, I think I may have caused the coolant level to recede. A lot of backfiring and rough running. Since then we've got the car back running fine.
I just added coolant, but since we are having the affects of a tropical storm (lots of rain here in Conroe, TX), I have not taken the car out to test it. BTW it is an automatic.
I'll post results later.
Thanks again,
Mike

[riber.bentsen]

You can call me Nick.. (Or Niels, but you 'mericans don't seem to be too familiar with that name)



And Landseer you have an incredible knowledge about these cars. I learn something in here every day!

[mproseusa]

Originally Posted by riber.bentsen

You can call me Nick.. (Or Niels, but you 'mericans don't seem to be too familiar with that name)



And Landseer you have an incredible knowledge about these cars. I learn something in here every day!

Thanks Niels. I totally agree with you re: Landseer's knowledge. He was a great help in getting my shark running.
Mike

[JK McDonald]

Hey mproseusa, Perhaps you have the very rare “High G-Force Sensor” option.

As mentioned above, you are right to normally expect an accompanying dash warning light for the specific problem that triggered the master warning panel. Perhaps, you are getting a "liquid level slosh" from a marginal fluid level that turns on - then - off the dash light while the master warning panel's holding function makes sure it has your attention. This could be potentially any fluid on board - low fuel, oil level, radiator reservoir, etc…

One other thought - I have seen the brake pad thickness warning circuits trigger some very strange results as well. This is especially true when the wiring had been poorly spliced, jumpered or hanging loose.

Good Luck, Michael

[mproseusa]

Thanks Michael. Good points. I have been '928' educated beyond my imagination. I am also concerned with the wiring as I've been able to "pull" insulation off wiring without much trouble. I do believe though that the water level in the tank was low. I had noticed fluid on the floor of my garage after running the engine for quite a while. The fluid appeared to be clear, and I took a slight taste of it. It was sweet, which is a good indicator of antifreeze. So when Niels suggested low coolant level, I wasn't to surprised, just embarrassed. Once I get the TB/WP changed out, I have brake pads, wiring, etc. on the to do list.
Thanks again,
Mike

[Mrmerlin]

if you getting low coolant i would suggest to replace the heater control valve and the short hose as well as the coolant bottle bottle cap, this should cure most leaks. usually a light coming on during hard starts is a low fluid.
you might consider adding fluid to the washer bottle,
top up the oil ,
and the coolant.
Also check the E brake connection under the hand brake lever ( single brown wire to switch)it can work loose and cause a temporary light

[mproseusa]

Thanks Mrmerlin. I didn't know the washer fluid level would give you a warning. I'm pretty sure that bottle is empty as I've never used the washers. Hopefully, today I'll get the car out and see if adding the coolant fixed the problem. I'll post the results.
Mike

[Mrmerlin]

if you look in your owners manual it should list all of the warning lights that come on when you twist the key to the run position IIRC yours should have a washer fluid level

[mproseusa]

Right Again Mrmerlin. It's right here on Page 28...Washer Fluid "warning light comes on when level in the windshield / headlight washer reservoir is down to 2 U.S. quarts". I never realized it was there. The light is in the Coolant temp / Fuel level gage.
Thanks,
Mike

[Mrmerlin]

any of the warning lights that come on can trigger the I light,
then the original issue can stop the trigger when the fluid returns to its just enough level

[Brett928S2]

Hi

Its not just fluid level warnings that can cause this...

I had exactly the same thing...master light came on but no other light to indicate which was causing it...

After a couple of weeks of it driving me nuts, my ABS light finally came on as well, which after a LOT of fault finding turned out to be one of the two ABS relays under the front wing....

So it COULD be ANY of the warning lights that come on when you turn on just the ignition....

And it may or may not be the coolant level ..... there is also a sensor for windscreen washer fluid level by the way...

All the best Brett

[mproseusa]

Originally Posted by Brett928S2

Hi

After a couple of weeks of it driving me nuts, my ABS light finally came on as well, which after a LOT of fault finding turned out to be one of the two ABS relays under the front wing....

So it COULD be ANY of the warning lights that come on when you turn on just the ignition....

All the best Brett

Thanks Brett ... very good information. Hopefully it was just the coolant level. It's been raining too much for me to check it out ... don't want to get the shark dirty
I'll post when I find out.
Thanks,
Mike

[Mrmerlin]

Usually the dash warning lights will burn out but the warning system still works.

IE a low coolant or washer may get left unattended for a while from a previous owner and the light may eventually burn out.
Since the new owner may not be aware of what the actual warning lights and positions should be,
the owners manual should be consulted,
this way you know what you should have VS what you do have .