Low fuel rail pressure causing issues

[Leviathan888]

Hi everyone. My 2008 A4 S-line 6-speed has started having some engine troubles. At idle (warm or cold) it seems to stumble a little bit. Vibrations are noticeable in the car now from engine. Also under hard acceleration in higher gears, engine will start misfiring pretty bad until you ease off the throttle. Also randomly when starting, car will crank for way longer than usual before starting. Cold or hot

Checked for codes and found 2 for fuel rail pressure. P0087 and another that was fuel pressure regulator mechanical malfunction. Reading live data shows fuel rail pressure to be ~630kpa (91psi) at idle. Way lower than it should be. But when I rev it above 1500rpm, that number skyrockets to normal values of 6000-7000kpa.

All the symptoms seem to be fuel pressure related, my question is which part of the high pressure system do I start with?

[Jayz691]

When was the last time you checked/changed your HPFP cam follower? When they blow through, and piston wears down, it'll often throw a p0087 and p2196(iirc).

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[Leviathan888]

LOL thats funny. I decided to check the follower after making this post and found only pieces remaining. Never changed it myself after purchasing the car from an auto wrecker, guess previous owner hadn't done it either. Worth it to replace the worn cam lobe also? I have a spare pump of unknown origin to grab a new spring, keeper, piston, and rod. Plus buy a new follower

[Leviathan888]

Photos https://drive.google.com/file/d/1lMd...usp=drive_link https://drive.google.com/file/d/1aHZ...usp=drive_link

[Phil Audi B7]

Your lucky it didn’t cause more damage yo the internals. I ve read conflicting info as yo when this came follower should be changed . Some say every oil change other say 30k miles. At 75k I checked mine and it had very little wear.

[Jayz691]

Your lucky it didn’t cause more damage yo the internals. I ve read conflicting info as yo when this came follower should be changed . Some say every oil change other say 30k miles. At 75k I checked mine and it had very little wear.

Lots of variables. Early/late revision intake cam, tuned and driving style, OCI, upgraded internals, etc.

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[Jayz691]

LOL thats funny. I decided to check the follower after making this post and found only pieces remaining. Never changed it myself after purchasing the car from an auto wrecker, guess previous owner hadn't done it either. Worth it to replace the worn cam lobe also? I have a spare pump of unknown origin to grab a new spring, keeper, piston, and rod. Plus buy a new follower

I would change the intake cam, and obviously HPFP/CF. Find as many pieces possible, and be a good idea to check your oil pickup in the near future. Can inspect your oil pump assembly/balance shafts at that time also.
Seen plenty CF 's blown through, but pieces.....Damm.

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[Theiceman]

ahh yes ... the new car discoveries....