Hi guys,
I bought an Audi off a guy I worked with and it ran fine for about four months, then one day the electrics died as I was driving home. Initially the radio turned itself off, then the lights faded, then the car cut out. When I tried to restart the car, a warning light on the dash read 'fuse', but I checked all the fuses that I could find (fuse box right side of dash, and three fuses in junction box on top of battery).
I had a fitter in work (bus company) take a look at the car for me, and he said it was a faulty alternator (90A). I ordered a new one and had it fitted, and within three days (~20 miles) the electrics once again died on me. I took it back to the fitter and he said that the new alternator was probably faulty and only providing an 'intermittent charge', so I had the alternator replaced and fitted. The car also had a battery (603) fitted, I checked in Motor World and they told me it should have a 720 fitted, so the new battery was fitted at the same time as the second replacement alternator. I noticed that the cable that runs from the alternator to the junction box on top of the battery gets hot when, and has melted part of the plastic in the junction box. I mentioned this to the fitter and he told me that he has tested all the cables and there is a charge running through all of them. He also had the car running for about two hours after fitting the new battery and alternator with a multimeter to test the circuit, and took it for a test drive and it seemed to be working fine.
This time it lasted four days (~30 miles) before the electrics went again in the same fashion as before. The car appears to have been a damage repairable, as the drivers seatbelt harness has been cut, and there are air intake pipes on the engine that have been snapped. The car also races when I first start it, and sometimes stalls when I'm driving, but I'm hoping that is just down to the air intake pipes and not something more complicated / expensive to fix.
I'm just curious to know if there are any common faults that may cause this kind of problem, or if there could be any components that could be causing the electrics to somehow short and prevent the alternator from charging the battery when driving?
