Results 1 to 8 of 8

Thread: Fuel Rail Pressure Test with VCDS

  1. #1
    Ross-Tech Employee Jef's Avatar
    Join Date
    Jan 2014
    Location
    HQ
    Posts
    1,924
    Post Thanks / Like

    Fuel Rail Pressure Test with VCDS

    Using VCDS to check/test fuel rail pressure on direct injection gas engines.



    This video also shows how different control modules will do things different because that is how the Germans designed them.
    Jef
    Ross Tech Support Team, Alpha Squad
    Auto-Scan, learn it, love it, live it... then check the fuses.

  2. #2
    NostraJackAss Jack@European_Parts's Avatar
    Join Date
    Jan 2014
    Location
    1001 State Route 17K Montgomery New York 12549
    Posts
    16,173
    Post Thanks / Like
    Great video Jef.........way to go! .......... now add mechanicals to part 2

    NostraJackAss foreseen problem's quatrain & FACTS about Fuel systems :


    When fuel PSI and Volume are in question, never omit doing actual mechanical measurements further use the OBD as a guide to compare to actual specifications obtained.

    Since VCDS only sees what the controller does, this is a very important thing to factor into a diagnostic path.

    OBD also can not detect vapor lock or air PSI being mistaken for fuel PSI!

    "Every time" I get one of those cars no one else can fix, it was because the OBD lied to the past repair shop just like Mr. Meter did!

    Keep these tips in mind and use serious safety precautions when working on the HPP system.

    NostraJackAss Has Spoken!
    European Parts Emporium/Performance / Immobilizer Solutions EPE
    Certified Master Trained NY/BAR/BAD 7076062/ASE/SAE/NASTF Legal Factory Authorized/Licensed GeKo/FaZit # 403738
    Specializing in Custom Services IE: "welding-fabrication" / EPA-SMOG Update or Pass-Thru-Programming / Data Transfer / Immobilizers & OEM Quality Parts
    Above Magic! No Written record, AUTO-SCAN or Appointment = NO HELP!
    www.FixMyEuro.com <<<<<CLICK HERE! or vwemporium@aol.com ( JPPSG & Unverified members need not PM me & Please don't email or call facility for free tech support...use the forum )
    Getting you CONTROL again of your property - TAKE IT! In Conjunction with.........

  3. Likes Bruce liked this post
  4. #3
    Verified VCDS User NZDubNurd's Avatar
    Join Date
    Nov 2014
    Location
    New Zealand
    Posts
    998
    Post Thanks / Like
    (non UDS) (very UDS)


  5. Likes Jack@European_Parts, Bruce liked this post
  6. #4
    Verified VCDS User
    Join Date
    May 2018
    Location
    USA
    Posts
    32
    Post Thanks / Like
    Hello All,

    Quick question. I have been told this test cannot be done on the 3.0L A4 engine. Anyone know if this is true? Thanks.

  7. #5
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    23,858
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by dodaman View Post
    Quick question. I have been told this test cannot be done on the 3.0L A4 engine. Anyone know if this is true? Thanks.
    "3.0 A4" engines have existing since 2002. Needless to say, they've changed a few times since then. Can you be more specific?

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  8. #6
    Verified VCDS User
    Join Date
    May 2018
    Location
    USA
    Posts
    32
    Post Thanks / Like
    Quote Originally Posted by Uwe View Post
    "3.0 A4" engines have existing since 2002. Needless to say, they've changed a few times since then. Can you be more specific?

    -Uwe-
    Well, I had some negative trim numbers on my 2005 3.0L. I found a vacuum leak and wanted to start looking into the fuel system. The numbers haven’t gotten worse, but they are still negative. (Just inside the +/-10%) The filter was replaced recently, and after reading about this fuel rail pressure test, I thought I’d try this. I don’t remember where I saw it, but somewhere I read this test wasn’t able to be performed on the 3.0l engine. That’s Why I was asking Uwe. Thanks.

  9. #7
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    23,858
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by dodaman View Post
    Well, I had some negative trim numbers on my 2005 3.0L. I found a vacuum leak and wanted to start looking into the fuel system. The numbers haven’t gotten worse, but they are still negative. (Just inside the +/-10%) The filter was replaced recently, and after reading about this fuel rail pressure test, I thought I’d try this. I don’t remember where I saw it, but somewhere I read this test wasn’t able to be performed on the 3.0l engine. That’s Why I was asking Uwe. Thanks.
    A 2005 A4 3.0 still uses low-pressure MPI injection, not high pressure FSI, and I don't think it even has a fuel pressure sensor, so no, I don't think you can do this test with a scan tool. I do think there's a port someplace on it that you can connect a mechanical fuel pressure gauge to.

    However, there are newer 3.0 engines that do use FSI injection on which it should be possible to run this test with a scan tool.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  10. #8
    Verified VCDS User
    Join Date
    May 2018
    Location
    USA
    Posts
    32
    Post Thanks / Like
    As always, thanks Uwe. A bit of a bummer. But Iíll look around for a valve to hook up a tester. Appreciate it.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •