Flickering instruments and headlights

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Jan 6, 2011 | 06:46 PM

Don in VT

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Instructor

Joined: Mar 2008

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Flickering instruments and headlights

Hi All,

Happy New Year. I have a new problem with the electrics on my 87.

Tonight coming home I noticed the headlights and instrument panel were flickering at the same time. My thoughts are:

Flakey ground
Problem with the alternator. The volts were at 14.8

Any thoughts on which ground is acting up ?

Regards,

Don in VT

1987 L98 daily drive
1990 ZR1 stored for winter

Jan 6, 2011 | 06:54 PM

93Rubie

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From: Indiana PA

This is going to sound crazy, but get your FSM out and check and clean every ground on the car. Not having them causes some freaky stuff.

Jan 6, 2011 | 07:22 PM

Midnight 85

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From: Hellinois

Finalist 2020 C4 of the Year - Modified

Could also be your regulator inside the alt getting ready to go bad.

Jan 6, 2011 | 07:50 PM

jfb

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From: Cincinnati, Oh USA

The voltage regulator in your alternator is oscillating. You can prove it by unplugging the alternator and the flickering will stop. You can replace the voltage regulator or you can have an auto electrical shop do it.

Jan 9, 2011 | 01:23 PM

jan-erik

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From: Oslo, Norway

Hi
I have an 85 4+3. Ithad flickering lights as you describe it and the voltage was as yours .
It was the voltage regulator which oscillated. I changed the alternator as it had some miles on it.
The flickering stopped and the idle became a bit better as with flickering the ripple is very high and the ECM get too much of that to cope with it.
Good luck

Jan 9, 2011 | 05:48 PM

RICEKILA

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From: Beautiful Down Town "SWINDLEHURST" Long Island NY

Quote:

Originally Posted by jfb

The voltage regulator in your alternator is oscillating. You can prove it by unplugging the alternator and the flickering will stop

Interesting

And if that's my problem also --- that would make 7 alts. in 8 years

I don't change my socks that often

Jan 10, 2011 | 07:45 AM

Ray Quayle

- 1986 Original Owner -

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From: North Yorkshire, England

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Quote:

Originally Posted by RICEKILA

I don't change my socks that often

Maybe that is what"s taking out the alternators!

Jan 10, 2011 | 06:02 PM

mechguy79

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Joined: Mar 2007

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From: San Angelo Texas

Quote:

Originally Posted by Midnight 85

Could also be your regulator inside the alt getting ready to go bad.

Had the same problem with my 90. I highly recommend keeping it simple. First, check your connection to the back of your alternator. Mine was green with corrosion. If you replace it use a heavy copper terminal with a hole just big enough for the terminal to fit through. You want to maximize the cross area of that connection. You will have to hammer the terminal to crimp it, but it is a lot easier then it sounds. You can use one of the heavy brackets right next to the wire and a hammer to crimp it down nice and tight.

Mine would only do it at a particular RPM, which happened to be cruising at 65 in 6th. I had an alternator shop rebuild it with a new internal regulator and bearings. Problem solved.

BTW, my voltage was never low, it just jumped around about .75 volts at a particular RPM.

Hope this helps.