Volks AutosBadger5
Results 1 to 14 of 14
  1. #1
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61

    2.5 tdi quattro AFB engine flat spot

    recently bought a B5.5 2.5 TDI Quattro

    Firstly I removed the turbo elbow and did the old "mr muscle" cleaner in and moved the vane actuator, car seemed to be a little more responsive, ive got a flat spot now, seems to be around 2500/2800 - 3100/3200 rpm, pulls fairly cleanly then flat, then pulls stong again

    plugged the car into a scanner today and we got 2 codes, 546 and 575

    the first one seems to be something to do with the connection between scanner and car, the second comes up as the MAP sensor

    so i took the MAP sensor out of the NS intercooler (what a PITA!) snapped one of the screws! devil of a job getting that out!!

    cleaned off the MAP sensor with some brake cleaner and put it back, not sure it its done anything really, still seems to have a flat spot

    any body else had this or suggest anything else it could be?

  2. # ADS
    ADS
    Join Date
    Always
    Posts
    Many
     
  3. #2
    6th Gear

    Status
    Online
    Join Date
    Jul 2007
    Location
    London
    Posts
    3,238
    I would change the MAF sensor first especially if the turbo actuator moves freely from min to max when you pull the rubber vacuum pipe- sign that the N75 is working fine. If you have VCDS then you can cycle the valve on and off so it shows if it works properly. Depending on mileage worn nozzles and worn pump heads will also account for loss of power, replacing the nozzles usually restores lost ponies !
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  4. #3
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    would the maf not have come up on the scanner as a fault? i dont have VCDS to check the frequency valve

  5. #4
    6th Gear

    Status
    Online
    Join Date
    Jul 2007
    Location
    London
    Posts
    3,238
    Maf will only come on diagnostic if open circuit or shorting to +/-
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  6. #5
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    right, got hold of vcds today to try and track down the running problem with the car, ran the auto scan

    only fault code recorded was 00575 08-00 control limit surpassed

    the car seems to go "ok" but when your under full throttle it goes flat sometimes then picks up again

    I checked the tdi timing aswell and the timing seems to be retarded



    would this explain anything?

    also i ran a log whilst driving, expected boost vs actual boost

    it seems to be over boosting, then cutting it ive seen upto 2.3bar! doesnt sound right!?

    if anyone can read and interperate this data (excel file) pm me your email and ill email it over

    also using vcds i checked the n75 valve, and looking at the vnt actuator, every 10 seconds or so the actuator would fully move up, then 10 or so seconds later move down, and it did this as long as i left the measuring block running

    it moved up and down freely and seemed to move full travel


    is there anything else i can try to diagnose the problem using vcds (and how to do it)

  7. #6
    Reverse Gear

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    16
    get.jpg
    meaby you adjusted that nut?

  8. #7
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    not touched it

  9. #8
    6th Gear

    Status
    Online
    Join Date
    Jul 2007
    Location
    London
    Posts
    3,238
    Do not touch that nut yet, whilst not very difficult to adjust with a bit of know how and computer, i would leave it as it is for the time being. How is the airflow ? The MAF or boost sensor can give same symptoms as well as worn nozzles...
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  10. #9
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    how do i test the airflow (i do have vcds available now)

    im replacing the timing belts, water pump, thermostat all rollers, tensioners and damper tomorrow

    i will adjust the tdi timing with vcds

    I think i want it to be above the mid line but below the top line is that right?

    should i be aiming for the middle of the mid/top lines or nearer one or the other?

  11. #10
    6th Gear

    Status
    Online
    Join Date
    Jul 2007
    Location
    London
    Posts
    3,238
    Can you send me the csv file/boost log please but not in excell, need to see it as it is from vcds. Please log measuring blocks 11, 8 and 1.
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  12. #11
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    will see what i can do tomorrow (when are the parts we've been talking about via pm available?)

  13. #12
    6th Gear

    Status
    Online
    Join Date
    Jul 2007
    Location
    London
    Posts
    3,238
    Injectors and turbo ? I have them off the car already...
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  14. #13
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    and chip/remap

  15. #14
    Neutral

    Status
    Offline
    Join Date
    Sep 2013
    Posts
    61
    *just checked, "psi tuning chip"

 

 

Similar Threads

  1. 1999 Audi A6 2.5 TDi V6, AFB Engine, cam tensioner advice required
    By colin_d in forum A6/S6/Allroad forum (C5 Chassis)
    Replies: 1
    Last Post: 20th June 2013, 21:00
  2. A4 2.5 Tdi Quattro - Severe engine knocking and loss of power.
    By richardj in forum A4/A4 cabriolet/S4 forum(B6 chassis)
    Replies: 16
    Last Post: 28th September 2012, 08:37
  3. Replies: 5
    Last Post: 13th September 2012, 13:22
  4. A3 2l Tdi s-line engine flat spot
    By Lee_C1 in forum A3/S3/Sportback (8P Chassis)
    Replies: 16
    Last Post: 8th June 2012, 21:27
  5. 2.5 TDi Quattro Flat spots
    By chris444cat in forum A4/A4 cabriolet/S4 forum(B6 chassis)
    Replies: 4
    Last Post: 25th January 2010, 10:47

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Single Sign On provided by vBSSO

Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

Content Relevant URLs by vBSEO