DTrumpet

Hello everyone. I am having problems with my Audi A8 2012 4.2. The problem is when starting the engine sometimes it does not turn on or passes work to do so and if I step on the accelerator when you are trying to turn it on it makes it easier. It happens more when the car is hot, overnight turns on Perfect. After it turns on it has no problem, it runs well and the engine is perfect. I already changed the battery and it’s still the same and pass him the vag and he has no codes. Someone could help me because I’m going crazy and I have no idea it could be. Best regards

audisrilanka

Did you check Fault code history?

DTrumpet

Yes and it doesn't have any code, it's what drives me crazy the most

yuvalw123

long shot, but look at the purge valve. ( the part is cheap and easy to replace )

DTrumpet

Reading here I have seen something happening to the A8 D3 in the engine revolution sensor that is in the gearbox, and it gives problems starting and I don't know if that happens on the D4s too. If anyone knows anything please I need help. Greetings to everyone and thank you for your help

audisrilanka

Take a check of your fuel pump, it can easily check by comparing the fuel pressure values by the scanner

KnappAttack

When mine would not want to start warm it acted the same. This lasted for tens of thousands of miles. Start fine when cold but forget it when hot. Same thing for me. Using the throttle it started better.

The dealer changed fuel injectors, low pressure pump & fuel filter and what actually finally fixed it was the hi-pressure pumps getting changed. Went almost another 100K miles before it stared doing it again. Traded it in and it wasn't wanting to start again when warm, so probably needs it done again, but I sent it down the road.

DTrumpet

Thank you very much for the info. I have it in the dealer but they haven't made the diagnosis yet.. but if they tell me to change many parts I'm going to tell you that they start with high pressure pumps, so that nop comes out so expensive because I have to pay for that heheh ... let's see if with that I solve and everything

Andrew12

I had this issue with a Subaru (2.2L), and a VW Passat (W8). The Subaru ended up being an intermittent cam sensor. The VW had an intermittent crank sensor. The Subaru had no codes. The VW had codes that helped me find the issue... Sorry, that is all I have. Both were really frustrating. Do you smell gas? like the engine is flooded.

DTrumpet

Today they delivered my car to me at the dealer and the problem was the high pressure pumps, they already changed them and everything ok. Regards and thanks for the help