wineohs

Hello,

I have been trying to resolve a hard start issue (particularly in winter NY) with my car for close to a year. I am not mechanically inclined and don't have a vagcom. After replacing the spark plugs, coils, battery, fuel injection system cleaned. Took to Audi dealer in Feb of 2018. Scan test code came back P0303.

• They checked:
  • Swap spark plug and coil to different cylinders--no misfires
  • Base fuel pressure--- good
  • Leak down for fuel pump, no leak down
  • Leak down on high pressure rail and found high pressure rail was bleeding down below input pressure
  • Removed intake and inspect fuel rail and found no leaks.
  • Checked all cylinders, no leakage at injectors.
  • Removed high pressure fuel pump and found fuel leakage, pump follower and pump worn through.
  • Replaced High pressure fuel pump and performed LOF (?) service due to fuel in oil.

Dealer started car next morning. Hard start was mitigated immensely, but not completely gone, but acceptable.

Fast forward to June 2019. I have been working with an indie shop that while honest and efficient is admittedly not an Audi specialist. Bring car in as check engine light car stuttered a couple of times. They scan and get service code Set/ 00135 (Sympton P0087) for fuel pressure too low. They feel it is the high pressure fuel sensor. They replace that. Check engine light is off when I leave indie shop. Drive 5 miles down the road and check engine light back on.

Can anyone with knowledge of this problem, please point me in the right direction.. Very frustrated and expensive thus far.

Thanks in advance.

kelisko

This thread will be useful: https://www.audiworld.com/forums/a6-...agian-2973687/

wineohs

Thank you, Kelisco. Hard to tell what solved the OP's issue. One interesting side note is that the engine light would stay on for a day or two and you could notice power loss when giving it a lot of gas. Then it would turn off for a day or 2 and power would be fine.

Just brought it back to the indie shop today with engine light and asked them to confirm that the error codes were pointing to High pressure fuel pump/sensor. They said yes and cleared the codes. I drove away with no engine light on for multiple hours with shutting the car off, letting it sit and then re-starting with no issues..........

Bizzare