SheriM21

Hey guys if you have any advice I’d love to hear it! I have a 2016 A5 cabriolet and for the last year or so it doesn’t want to start when the engines warm. If it’s a cold start, starts no problem same with a hot start, but if the car has been sitting for anywhere from 5 mins to an hour the car won’t start unless I press on and off my accelerator. There aren’t any codes, and once the car starts it runs fine. But like I said I try to start it and it cranks over but doesn’t turn on until I push on the accelerator. I have had my spark plugs and fuel injectors replaced, and still no clue.

SMac770

Long crank to start for warm restart with the B8 2.0T has come up a few times in the B8 A4 forum. Can't recall the resolution, leading thought would be the HPFP not retaining pressure (since you've already replaced injectors). If the pressure drops with the heak soak temps up, the fuel can turn to vapor and that doesn't pump easily. For the EA888 Gen2 2.0T, the fuel pressure ranges from ~4,000 kPa idling to 15,000 kPa WOT. But if I've done a decently long trip (say, 20 min drive) and see it idling at 4,000 kPa and then turn off the engine and watch, it'll climb to over 17,000 kPa from the heat soak.

Do you see your fuel pressure make 15 MPa (150 bar) on WOT, and do you see it rising past that on engine off?