Audi A3 8P TDI Starting problem

[Xtravaganza]

My car wont start on the Flat but will start on a Slope (facing up) fuel filter is less than a year old and (MANN filter) using Shell fuel and Premium shell too. 2006 1.9tdi BXE 103ps 140k, Once started runs and drives perfect re starts fine on any surface. thinking I'll check the pump in the Tank and change fuel filter anyway. seen suggestions for water in tank, timing, (belt looks fine), leak back on fuel line, air in system etc. Changed temp sender and had new cam & crank sensor fitted. Battery is strong. any thoughts Please.

[N7GTX]

Probably injector leak off running back to the tank overnight. A simple manual injector leak off test will show which injector(s) is at fault or, if you have access to someone with a Bosch KTS diagnostic tool this will show the condition of the injectors on a graph - green/orange/red - without the need to touch them.

Most decent garages have leak off test kits (cheap on eBay) and it takes only a few minutes to do. 4 bottles are attached to the return pipes on the top of the injectors. Engine is started and the unused fuel to each injector goes into the bottles. All 4 should be the same and take some time to fill up with the engine idling. If one fills the bottle quickly then that injector has failed.

Edited by N7GTX on Thursday 27th January 14:32

[Xtravaganza]

Thanks so much I'm looking into doing it myself.