Notices
 

  

User Tag List

Thread: Audi a8 sudden drop in fuel economy

Results 1 to 5 of 5
  1. Audi a8 sudden drop in fuel economy 
    #1
    Join Date
    Sep 2013
    Location
    Glasgow
    Posts
    3
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)
    Good Evening fellow members, hope you are all having a swell weekend!

    I have a funny one here,

    Having looked at various sites on google and other forum posts this may not be an issue for most but it is doing my head in!

    I have a 2006 Audi A8 D3, it's a 3.0tdi with an Economy map on it

    it sits on around 173k miles.

    The issue I am having is the following:

    1. Cold starts - it chokes quite a bit when starting, may 6-7 seconds before it fires, once it does there is a noticeable amount of smoke from the rear end, blueish blackish in colour. I believe this may an issue with Glowplugs maybe? I thought I would ask here for another opinion.

    2nd and most importantly.

    Over the past 4 years of ownership, any time I would join the motorway the MPG could go over 50mpg with ease, I have managed to reach even 60mpg at one point, this is no BS. 900+ miles out of 1 tank of fuel was easily achieved. Locally it would be around 40+ with ease

    HOWEVER, most recently i have noticed the car struggles to even touch 42mpg on the motorway! Locally it does not go over 30mpg I drove to London from Glasgow and I averaged 42mpg and pretty much the same on the way back. This is including the fact I always used premium diesel (the brand depends on what is more convenient to get to at the time of needing fuel) I managed to get just over 600miles out of a tank. So losing 300 miles surely raises some eye brows!

    Having read other posts I understand that most people would be VERY happy with these figures. However, for me it is a bit of a concern.

    I have read that a terraclean may be a possible solution for this, I have had this done on other vehicles and have been happy with the results but in this case I fear there could be something underlying.

    Any advice offered would be highly appreciated.

    Thank you all!

    Beel.
     
    0 0 0
     

  2. Re: Audi a8 sudden drop in fuel economy 
    #2
    Join Date
    May 2013
    Location
    Wisbech
    Posts
    241
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    8 Post(s)
    Regarding number 1 , glowplugs have nothing to do in this temperature . If we would have temperatures sub zero then yes. You might have issue with supply fuel or issues with injectors.

    Sent from my ONEPLUS A5010 using Tapatalk
     
    0 0 0
     

  3. Re: Audi a8 sudden drop in fuel economy 
    #3
    Join Date
    Feb 2016
    Location
    Blaydon, North east England
    Posts
    242
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    30 Post(s)
    I would get it scanned and see what happening with it. Also do simple checks like cracks in pipes or pipes blown off etc. Could it need a service or the fuel filter is blocked?
    2015 A6 Allroad 218 - NEW
    2012 A6 Avant SE 3.0TDi Multitronic - OLD
     
    0 0 0
     

  4. Re: Audi a8 sudden drop in fuel economy 
    #4
    Join Date
    Jun 2006
    Location
    UK, Registered Homeless
    Posts
    2,289
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)
    Is it as quick as usual to warm up?
    Does the temp sit at 90˚c on a cold day, at all speeds?
    There is a inline coolant regulator beside the auto box on the 3.0 tdi and it fails open and coolant is no longer regulated by the thermostat and wastes fuel and gives poor heater output- common fault.
    Audi A8L- 2006 - 3.0TDI
     
    0 0 0
     

  5. Re: Audi a8 sudden drop in fuel economy 
    #5
    Join Date
    Jan 2007
    Location
    Aberdeen
    Posts
    1,305
    Post Thanks / Like
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    28 Post(s)
    Is it using oil?
    Current- S3 Sportback Nav S-tronic, Mythos Black, B & O, Comfort Pack, Lumbar Support, Lunar Silver interior.
    Gone-A6 C7 biturbo saloon, A6 C6 3.0 tdi Quattro saloon, A6 C5 2.8 Q Avant
     
    0 0 0
     

Similar Threads

  1. Question Drop in fuel economy - thermostat or CTS?
    By herby0001 in forum Golf MK4 - 1999 - 2004
    Replies: 5
    Last Post: 19-07-2013, 09:15 AM
  2. Question Sudden Drop in RPM during heavy rain.
    By Klevo in forum Polo - Derby - Lupo - Fox
    Replies: 8
    Last Post: 13-02-2012, 10:50 AM
  3. Sudden power drop off when excellerating in 3rd
    By Digidick in forum Passat - B5 Forum - 1997 -2005
    Replies: 10
    Last Post: 05-01-2009, 10:38 AM
  4. Sudden drop in mpg?
    By MankyManning in forum Audi A4 - B5 Forum - 1995 - 2002
    Replies: 4
    Last Post: 09-11-2008, 01:02 AM
  5. New Passat :: Drop in Fuel Economy
    By nheather in forum Passat - Archive Topics
    Replies: 10
    Last Post: 23-10-2007, 08:02 AM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  




  


Disclaimer: VW Audi Forum is an "independant enthusiast website", administered in line with guidelines supplied by VAG in the UK, and is in no way related to any of the Worldwide Volkswagen,Audi,Seat,Skoda,Bentley,Bugatti,Porsche or Lamborghini group of Companies. For official up to date information on any of there vehicles, please visit the official websites. Any comments made throughout this website, are the views of the respective poster, and in no way represent the views of the VW Audi Forum Administration, or the worldwide Volkswagen & Audi Group of companies.


VW Audi Forum do not vet and are not responsible for any information which is posted in this forum. All content is viewed and used by you at your own risk and we do not warrant the accuracy or reliability of any of the information.


Copyright: Certain "words", "phrases" and "Images" used on this website by the Administration are "Copyright" of Volkswagen GB, Volkswagen AG (Germany), Audi GB, Audi AG (Germany), Volkswagen Motorsport GB, Volkswagen Motorsport AG (Germany), Audi Motorsport AG (Germany), Volkswagen Racing GB, Bentley, Bugatti, Porsche and Lamborghini. No image can be replicated by anyone WITHOUT the relevant Companies written permission.


All trademarks and copyrights remain property of their respective owners.

No part of the VW Audi Forum website or forum may be reproduced without written permission from the site administration


PLEASE NOTE - PERSONAL ABUSE, ABUSE AGAINST THIS OR ANY OTHER WEBSITE OR ANY COMPANY WILL NOT BE TOLERATED. OFFENDERS WILL BE MODERATED OR EVEN BANNED.


This website and forum are best viewed at a minimum resolution of 1024 by 768.



  



- VW AUDI Forum - The #1 Volkswagen (VW) Group Forum - Volkswagen (VW) - Audi - Seat - Skoda - Bentley - Bugatti - Lamborghini - Porsche - VW Audi Forum -


- www.vwaudiforum.co.uk - www.vwaudiforum.co.uk -