Audi A8 4.0 TDI 2004 Starting issue

Good evening !

Any help or advice would be hugely appreciated. I own an Audi A8 4.0 tdi 2004 model, the car starts well from cold any time if year but it started taking longer and longer to start when it was warm but always started, the first time it failed to start, I replaced the battery and this seemed to help the problem initially for the first 2 wish weeks, then it returned to how it was before. since then around 12 months ago (it really gets used now I work away and cannot rely on the car what so ever) the alternator is charging the battery but I'm unsure on how well it dose, usually sits at 13.2v but if held at 1200 rpm sits at between 14.2v and 14.5v as I would expect. and maintains at least 13.8v to 14.4v when driving.

I initially thought it was the alternator but i guess it is putting charge back into the battery but is it enough?

I then thought starter motor as it seems lazy and turning over slow but its fine when its cold. but when boosted (I don't like doing it) it turns over really well and starts perfectly when its hot. I have investigated the location and feasibility of changing the starter motor and it seems like a total pain in the **** job !

I guess I'm just going round in circles pulling my hair out and this is really ruining the A8 experience. so any help and any info the help me sort this out would be seriously appreciated.

if any of you could also tell me what the alternator for this model should charge at would be brill.

Cheers
Reiss

So you have had it fault code read to see if the sophisticated engine management system has picked up something such as glow plug failure, a service item?

To be clear, you don't have problems starting when engine is cold.
When engine is up to temp and you stop for a short time, when you come to restart the starter turns over slowly as if the battery is drained?

In several cases, this was found to be the main power cable connection which is just to the right of the driver's right foot behind the carpet/insulation.
There is a thick cable and a terminal box within a metal and plastic box here.
People have found signs of overheating, soot on the insulation and inside the box, shrivelled heat shrink, dark insulation.
People have found this connection feels hot on affected cars.
When the battery is low and you start the car, the charging current makes the connection hot and doesn't charge the battery very well and then when you come to do a hot restart, the current can't get through to the starter and the battery is still low to make things worse.
The attempts to start the car make the connection even hotter. Once cooled down for 20-30 mins, it usually starts.
3.0TDI Hot Start Issue, Very Slow Cranking - A8 Parts Forum

http://forum.a8parts.co.uk/showthread.php?t=13499

Attachment 35915

Snapdragon I owe you a pint or 10 !!! so I stripped it down (about 10 mins) pull the cabe off and hey presto it was the same as the one photographed !
I also noticed that the nut on the terminal was plated with something so cleaned that up, crimped and soldered a new end on to the the cable and its been perfect ever since !

Turns over better and faster and charges at 14.2 amps absolute life saver !

Thank You

Glad you sorted it - that was quick I would have pontificated for weeks.
I'm just passing on someone else's knowledge!
Same issue on the Q7 but it's under the brake fluid reservoir...
#085(6) пайка плю�ового кабел�(от акб) Audi Q7,VW Touareg - YouTube