S5 Fuel Issues?

[ebergend]

Hey All

Been having some issues with my 2009 S5 lately and need some help. Got a check engine light and EPC when the car is started. Starts fine when warm but will take a second or two to turn over in the early morning (give the gas petal helps get it over). Got the following codes read:

P0171 - too lean bank 1
P0174 - too lean bank 2
P2293 - Fuel pressure regulator 2 performance
P0087 - Fuel rail/ System pressure too low

Not sure where to start. Already replaced the low pressure fuel sensor on the top of the drivers side HPFP but the only difference it made was turning on EPC. When swapping back to the old sensor EPC does not turn on allowing me to rev over 4k rpm but the car misfires pretty bad in the high rpm.

Any insight would be helpful, seems like everything I am finding online pertains to the 2.0T engines and the cam follower going bad. Would think that if that were the case here it would only be on one bank of cylinders rather than both...

[new2s5]

Had similar problem here. Had engine de- carbon treatment done. All good now.

[pr1malr8ge]

Fuel Filter first then look at fuel pump.. Low pressure is generally those two items which in turn can and will trigger the reg perf and bank leans. Possibly also could be a leak in the fuel line but you would smell fuel if parked in an enclosed lot.

Had similar problem here. Had engine de- carbon treatment done. All good now.

While a "gunked" up engine can/will run like what the OP has indicated. It shouldn't toss Fuel system codes.

[ebergend]

Thank you for your input guys. I have done a carbon clean a few months ago. Do you know if the 4.2 v8 S5 have a fuel regulator outside the fuel tank? I saw something that shows there might be an access panel under the carpet in the trunk to access the fuel pump which may help me out a bit.

[ebergend]

Ordered a new fuel pump/ filter that should be in this week. I found the access panel in the trunk to access the pump in the tank so hopefully the swap wont be too bad. I will post an update once I have the new pump and filter installed.

[buchi1728]

Did you ever figure it out? Got an 08 S5 with the same exact codes and dont know where to start

[BuyTheWarranty]

Sounds like a failing HPFP or injector issue. I suggest reading through this:

https://www.audizine.com/forum/showt...ing-Issue-Help