I have an 88 model Holden Astra, but its exactly the same as a pulsar and I have removed the old stereo only to find I have no idea what the colours of the wires are in the car.
The colours are as follows:

Black Blue/Red Yellow Red
Black/white orange black/pink Brown

Can some one please tell me what these colours are so I can hook up my new stereo ?
Thank you.

I did an install in a mates 88 last year, so if Ill give this a go.

Black is earth, clearly. But I recomend useing the earth wire on your new stereo and earthing to the dash frame somewhere.

Yellow, I think is constant power, and red is switched power from the ignition.
Im about 99% sure on that, as it seems to be the same for all Japanese cars, but it might pay to test it first with a test light.
A car of that age might have had all sorts of dodgy things done to it, my mates car for example had no switched power supply, and I had to run a new wire from the cigarette lighter.

orange black/pink Brown are from memory the speaker wires. I think they shared a common grond, which was the Black pink, and orange and brown were left and right.
However Black white is used by other Japanese manufactors as a speaker earth, so its possible that Black/white orange black/pink Brown are all speakers, but you will have to work out which is left and right.
If you listed them as they are on the factory plug then Black/white orange will be one side, and black/pink Brown will be the other, and the wires with the black stripes will be the speaker eathers.

That leaves Blue/Red, which is an odd one.
My guess is its the accesory wire, for light dimming on some head units, or working an electric arieal, however that wire is normaly just blue.

Good luck.

Moppie, thank you very much mate, I would have been lost without your help. Now I can get that new stereo installed.
Thanks again buddy !