How to set the ignition timing on a 1987 audi 5000 S ?

Most auto parts stores will clear all error codes for free.
Or you can buy a scan tool from them that will let you clearand reset the codes.

Hi, (Please send me back your e-mail address, in order to keep in touch with your Audi 5000 problem. Maybe you need bigger pics)
"TDISLine" add to you another picture with positive battery cables on your car:

The starter motor location:

You need to find your timing belt or timing chain. There should be specific marks on the pulley's, most are straight at 12 o'clock.

Sure, no problem. The fluid is not under pressure in the reservoir. Just be aware, do not overfill the reservoir, the fluid expands as it gets hot.

Under the back seat on the passenger side.

change ur fuel pump ,

If you go to ebay, under "audi 5000 87 ignition" you will see the full ignition block with new keys, and its only $49, and you can offer less since its best offer. You can check local junk yards, and parts stores, but you may not find the part due to the age, hope that helps

The ground? You'll have to be more specific. There are several grounds involved in starting the car. Whichever it is, it'll have to be repaired. This repair should be fairly simple -- replace the broken cable or clean the connection, then replace. There's no way to bypass the ground. Let me know which ground it is, and I'll try and look it up in the repair manual, and give you some tips on how to track it down and fix it.

Do you have headlights if you turn them on. Sometimes if a battery is clear dead and you jump it and it will depend on the gauge of wire in the jumpers whether it will start right off or not. Another scenario is the battery you bought is not good or fully charged. If you have a battery with less than 11 volts it probably won't energize the starter.