Hi guys/girls,

 

I have a theory so please sit tight lol.

 

Audi A6 Avant C7 - 2014 2.0 TDI ultra  S-tronic

87,600 miles 

full service history

full gearbox service history (3 gearbox services, 2 with Audi and 1 with an Audi specialist) prior to my ownership.

 

so I have an issue where in the mornings the car tends to stall either on first pull off or within the first few minutes, once warm it’s fine.
 

I have the AC windscreen clear on, drivers heated seat on and rear demister on, the headlights are usually on. 

at first I thought gearbox issues or clutch, but I’ve been messing around and it doesn’t do it if the electrical demand isn’t high. 
 

the alternator is a bit noisey when cold, and I planned to replace it but didn’t want to right now as it’s expensive and can live with noise for a little bit if I need to spend money elsewhere like gearbox.

 

however today I decided to use Carista live data.

 

todays test showed 75% battery charge just after first start up, voltage at ect was 14.6v in nice it turned on my windscreen clear button, rear demister and heated seat (as well as radio and drls on) it dropped to 14.1v. As I pulled away it dropped to 13.8v and stuttered a little. 
I came to a stop at the end of the road and went to pull away, it stalled and I saw 13.4v for a split second. 
 

is it possible a faulty alternator is the cause of my issues? 
 

I initially assumed clutches or gearbox fault. But after watching the voltage and logically thinking, perhaps the power usage is too much strain on a failing alternator? And it can’t regulate the draw. 
 

I’d love to hear your thoughts and any suggestions on other tests I can do to try and narrow down/ confirm the fault before spending money.

 

my other consideration was doing a calibration / reset on the gearbox incase it wasn’t done after the last gearbox service.

 

much appreciated,

 

Dave 

Edited February 4, 20251 yr by DaveOL89

I'd say the problem is electrical, so I suggest you get the battery and alternator tested professionally as a first step. It doesn't matter what voltage you measure, the battery may still be defective enough to interfere with the ignition system.

Very good point. I’m definitely leaning to an electrical issue and not a clutch issue based on my findings so far