# 1987 audi 5000 voltage problems and more



## saabspg (Jan 28, 2009)

just got a 5000cs. car starts and runs great but if you let it idledown all the way the battery light comes on and car dies any ideas?? battery was tested and its fine running 14 volts or so. alternator belt if fine also. can the alternator be tested?? car is also running code 2111. also hissing coming from behind differential locks under cd player. when i inspected this i see 2 vaccumm lines that make a T to 1 then it stops.i dont thinkit has anything to do with the diff switch. i will try to take a pic of it.


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## oldsklaudidub (Aug 29, 2006)

*Re: 1987 audi 5000 voltage problems and more (saabspg)*

If the alernator belt is tensioned properly it is 100% the alternator that is bad. Now Id bet that the original spec 90 amp. Sounds like the alternator is not throwing enough amps at idle so the voltage reg might be bad but the alternator is more likely at fault. Before going out for a new alternator, take a steal brush and clean the contacts on the voltage reg and see if that fixs it.
What you will want to replace it w/ is the 110 amp alternator from the 89 model year and up, you will just need the mounting bracket for that alternator since it is larger. The rational is that for the same price as the stock alternator why not upgrade.
I run the 110amp on my 88 5ktq and it basiclly solved all my electrical problems.


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## Thunderbox (Aug 29, 2008)

*Re: 1987 audi 5000 voltage problems and more (oldsklaudidub)*

just now reading this post and I have to agree with the upgrade to the 110 amp.
I did this and my 86 is now running better than ever. You can find a bracket from someone parting a 89 or newer type 44.


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