skegeeman1

I just replaced the high pressure fuel pump on my 2011 Q5 2.0 TFSI. Last night when I first finished it took a few minutes for the lines to prime, but it ran great when I took it for a test drive. Fast forward to this morning when I took my wife to work. on the way back I stopped at the parts store to pick up some new coil packs for my A5 that I am rebuilding, I had been driving for about 45 minutes.. When I got back in the car it wouldn't start it was acting like it was not getting any fuel. I pumped the gas a couple of times and then the car started. It drove fine all the way home with no hesitation. When I got home I turned it off, then tried to start it again and the same thing happened. I had to give it gas to get it started.

This evening I got in it and it started right up with no issues. I took it for an extended test drive (about 30 minutes), and it again ran perfectly. When I got back home I turn it off and it started up again with no problems.

Does anyone think I bought a bad pump or was it I still maybe had some air in the lines?

Thank you in advance!

SMac770

Could have been some hiccups settling in. Hard to say as there's no fuel pressure actual vs specified log to assess. Run with it and see if it persists. Some people have had an issue with warm restarts, which typically meant replacing the HPFP. Something about "vapor lock", but can't say the cause was ever really understood. Why were you replacing the HPFP?

skegeeman1

I replaced it at the advice of Audi service. I was there to get a key created for another car I had bought at auction and I had mention my Q5 seemed to have an issue where it was sometimes hard to start. I thought it was the battery. He told me to sniff the oil fill cap when the car was cold and if I smelled gas it was the HPFP goin bad. I have been running it a couple of days and it seems to hard start when it is warm.

I think I got a bad pump. I bought another and will be trying that.