My car was fine since I got it, but yesterday I was idling (park) waiting for someone when the car just stalled... I was like ??.. Ever since, when i try to start it, it cranks but never starts.. My fuel tank is full, battery is good. Tried checking for codes through vag-com and there are No codes. Tried starting it hot (when it stalled) and cold (anytime afterwards).

Could it be fuel pump ? Cam/crank sensor? How can I check

 

Failed fuel pump doesn't throw a code. Cam or crank sensor should show code.
If you hear it run, could still be bad. Disconnect fuel line at filter or at engine...run pump with key or jumped wires.
If you don't hear it run, check fuse/relay or try jumping pump wires.

 

I just had my fuel pump replaced. I recieved to code when it was failing. I did take it to dealer since its still under warranty but they said they had to replace both fuel pumps. So there is more than one pump to check.

 

There's only one fuel pump in a D2 (97-'03). If there's 2 in a D3, that's news to me.
I've heard of other people handed that line by dealers.

There is a "leak detection pump" on D2's (D3 ?) that is part of a start up test the car performs (or diagnostic test procedure), that tests the system for leaks (tank, line, evap),...not a part of the fuel delivery system, but will trip a code if it detects a leak at start up or diagnostic test. The code tripped has nothing to do with the fuel pump or it's operation or failure.

 

There are no codes whatsoever.. So i have to find out by trial & error. Tried jumping the pump directly with 12V but I dont hear anything.. (normal since it's so deep in the tank?) or should i hear it?

 

Not normal, if you jumped the green w/red stripe wire (hot) and brown (ground). Plus, when you first turn on the key, esp if you 'touch' the starter, you should here it run a few seconds. It's actually toward the top of the tank. You should hear it.

 

Had similar issue with my '04 A8L. Wouldn't start for beans. Gave it a jump with the Explorer...floored it on crank and it started. Got it to dealer who said the Access Control Module was DOA. Expensive as heck - $600.00 part and it requires everything including keys to be reprogrammed. Hope it's not that.

 

My first thought is always the timing belt. How many miles or have you had it replaced recently?

 

No offense, but T-belt is always my LAST thought. Granted, a broken belt would result in "crank, no start" and if this was the case, it would have been sudden breakage since it went from running well to nothing. Had the belt been loosening before, it would have been noisy, erratic and thrown multiple cam timing codes. And if it's broken, every time you crank, you're slamming pistons into open valves...both heads rebuild or replace. Easy enough to check: remove or loosen driver's side cam belt cover, crank and watch for movement...even if belt appears OK at standstill (which is possible, if broken near crank), turn it over and watch for movement...if it broken, you've probably already destroyed valves anyway.

There's a lot of unfounded paranoia about cam belts, unless at astronomical mileage, catastrophic failure of a tensioner or other related part or installed by an idiot...Even then, very rare in an A8 engine. The belt is not simply a rubber bad...it's heavily reinforced and as strong as a chain...many high powered motorcycles use the same design in place of drive chains to the rear wheel.
Yes, ANY part can fail, but personally I worry about my belt almost as much as a satellite falling on me....but I DO inspect the belt regularly, like anything else...AND I also watch the skies for falling debris

 

Engine control unit?