I had to create an account here just to say THANK YOU
I had the same problem, took a 16mm2 battery cable and connected it between the negative batterypost in the engine bay as you described, and the other end to the exhaust manifold. A big difference!
Hi have the same earth problem as it has lazy start like battery flat or sometimes not even turning over, I connect a jump lead from negative post under bonnet to the engine and starts so is definitely earth problem, Where is the best place on engine to add an extra earth as it is a Q7 just like yours and noticed you said made a big difference Thanks
Slow start
in Audi Q7 Club
Posted
Hi have the same earth problem as it has lazy start like battery flat or sometimes not even turning over, I connect a jump lead from negative post under bonnet to the engine and starts so is definitely earth problem, Where is the best place on engine to add an extra earth as it is a Q7 just like yours and noticed you said made a big difference Thanks