Chris NottEM Tuning
Results 1 to 15 of 15
  1. #1
    darylpurnell's Avatar
    My other car has two engines!

    Status
    Offline
    Join Date
    Apr 2007
    Posts
    5

    S4 BI-Turbo MAF problems

    i have a 1999 S4 bi-turbo which i have been running for a couple months without a MAF connected (waiting for funds to buy a new one), as the car would not accelerate or rev above 3000rpm with it connected.
    i have just bought a new MAF and put it in the car and it runs just as bad as the origional one. i sent this MAF back because i thought it was faulty and they sent me a new one, but upon installing this new MAF the problem is still there.

    when the new MAF is connected and all fault codes removed from the ECU i took the car for a test drive (trying hard not to stall the not so smooth engine), when i got home no new fault codes were generated.

    The MAF has all the signals connected to it 12V 0V and 5V and i have buzzed the signal wire to the ecu and it was ok.


    I am stuck, has anyone else had a similar problem??, do i need to let the ECU adapt to this new sensor??

    thanks in advance for any replies

    Daryl

  2. # ADS
    ADS
    Join Date
    Always
    Posts
    Many
     
  3. #2
    Beerzo's Avatar
    Masa'warty 3200... Talk To Me!

    Status
    Offline
    Join Date
    Feb 2006
    Location
    Scotland
    Posts
    1,241
    Not sure if this would help but try disconnecting the battery for 30 mins ro so to allow the ecu to reset.

  4. #3
    jcb
    6th Gear

    Status
    Offline
    Join Date
    Sep 2005
    Location
    uk
    Posts
    4,077
    i should think running it without a MAF is inadvisable.
    would defo have to reset the ECU when changing something of that significance

  5. #4
    darylpurnell's Avatar
    My other car has two engines!

    Status
    Offline
    Join Date
    Apr 2007
    Posts
    5
    disconected the battery for an hour reconected and it is still the same.

    just tried clearing all fault codes first and will leave off for a lot longer, is there another way of reseting ECU?

  6. #5
    darylpurnell's Avatar
    My other car has two engines!

    Status
    Offline
    Join Date
    Apr 2007
    Posts
    5
    just had a better idea i put in my spare ecu which has been disconected from the battery for two months, still the same problem !!!

    Help

  7. #6
    Phantom_A4's Avatar
    3rd Gear

    Status
    Offline
    Join Date
    Jan 2006
    Location
    Southwater, United Kingdom
    Posts
    562
    Sparkers might be mis-firing, i had a similar problem. Wouldnt idle right at all and the revs kept fluctuating betweent 1,100rpm and 700rpm. One of the sparkers had perished quite badly so replaced all 6 and ran just like new.

    Have you tried looking in to that?

  8. #7
    darylpurnell's Avatar
    My other car has two engines!

    Status
    Offline
    Join Date
    Apr 2007
    Posts
    5
    it runs sweet as a nut with the maf disconected (although lower power) but i take look at the sparkers tomorow. thanks

  9. #8
    ZeroK66's Avatar
    1st Gear

    Status
    Offline
    Join Date
    Jun 2004
    Location
    Devon, UK
    Posts
    246
    Sounds really dodgy, you should really get this checked out by a specialist. heathchecks are as little as £45 and by the sounds of things would save you from a serious problem.

    See MRC tuning...
    Facelift Imola S4 | Custom: K04's, Tubular Manifolds, 3" DPs-> 2.75" Catback | FMIC | H&R Coilovers + ARB's | Brembo 8-Pots | SS + DTS | 503HP/475lbs/ft | 1800W RMS

    Sold: Audi A4 (B5) 2.8 Quattro | Ivory Pearl
    Melted: Corrado - IHI 1.8 20vT: 343BHP

  10. #9
    Turbo Lag FTW's Avatar
    Hate those none insured you know who types

    Status
    Offline
    Join Date
    Feb 2007
    Location
    Carlisle, Cumbria. Not Geordie nor Scotch!
    Posts
    233
    When you connected your new MAF did you let the car idle for 10-15mins so the ECU could adapt to the new part?
    From what Ive heard any modification to the air supply inc sensors requires the car to idle for 10-15mins without any acceleration as to let the ECU adapt and correctly calibrate itself. Otherwise problems will arise as the ECU will struggle to deliver the correct amount of air to the ignition process.

    I could be wrong tho, just remember reading it somewhere on the american forums.

  11. #10
    Neutral

    Status
    Offline
    Join Date
    Oct 2006
    Posts
    88
    Not sure if this will be your solution, but thought id mention it. I had the up and down idle and slighty rough running. I suspected the MAF and disconnecting it fixed the idle, but the car was a much rougher. - guess a limp home mode. Reconnecting the maf improved the running, but also brought back up and down idle and the car was still slightly rough and jerky.

    Turned out had to re syncronise the thottle (Drive by wire) with the acelarator. That fixed my car.

  12. #11
    Reverse Gear

    Status
    Offline
    Join Date
    Jan 2007
    Location
    Doncaster
    Posts
    16
    Quote Originally Posted by sun and kath
    Not sure if this will be your solution, but thought id mention it. I had the up and down idle and slighty rough running. I suspected the MAF and disconnecting it fixed the idle, but the car was a much rougher. - guess a limp home mode. Reconnecting the maf improved the running, but also brought back up and down idle and the car was still slightly rough and jerky.

    Turned out had to re syncronise the thottle (Drive by wire) with the acelarator. That fixed my car.

    pray tell how did you do that? mine has the rough idle and was told it was because of a new TB that was fitted and needed 'syncing'

  13. #12
    ZeroK66's Avatar
    1st Gear

    Status
    Offline
    Join Date
    Jun 2004
    Location
    Devon, UK
    Posts
    246
    I would stop playing guess work and give MRC a call. I would expect they would be happy to offer some advice. Failing that a visit would be highly recommended.
    Facelift Imola S4 | Custom: K04's, Tubular Manifolds, 3" DPs-> 2.75" Catback | FMIC | H&R Coilovers + ARB's | Brembo 8-Pots | SS + DTS | 503HP/475lbs/ft | 1800W RMS

    Sold: Audi A4 (B5) 2.8 Quattro | Ivory Pearl
    Melted: Corrado - IHI 1.8 20vT: 343BHP

  14. #13
    Neutral

    Status
    Offline
    Join Date
    Oct 2006
    Posts
    88
    Quote Originally Posted by pt7550
    pray tell how did you do that? mine has the rough idle and was told it was because of a new TB that was fitted and needed 'syncing'
    Hi Pt7550

    I used VAGCOM, i had the free shareware and an ebay bought wire previously. But to fix the problem i had to part with 100 dollars to RossTech and now have full VAG com. then I fixed my car in a couple of mins, after weeks of messing around.the instuction for re sync the throttle is on the ross tech web site - dead easy.

  15. #14
    A4 2.4 30V PES Supercharged

    Status
    Offline
    Join Date
    Sep 2006
    Location
    Derby
    Posts
    159

    Throttle Body Adaptation

    Disconnect the battery negative for several minutes put it back on, switch the ignition on without pressing the gas or starting the car, and leave for five minutes, you may hear the throttle resetting itself, start the car without using the throttle and let it idle for five minutes.
    This is the manual way of ressetting the throttle this needs to be done when ever the battery is disconnected for a period of time. This can fix poor idling and hesitant acceleration. Let me know if this helps.
    A4 2.4 30V

  16. #15
    A4 2.4 30V PES Supercharged

    Status
    Offline
    Join Date
    Sep 2006
    Location
    Derby
    Posts
    159

    Throttle body alignment

    Quote Originally Posted by mckay9uk
    Disconnect the battery negative for several minutes put it back on, switch the ignition on without pressing the gas or starting the car, and leave for five minutes, you may hear the throttle resetting itself, start the car without using the throttle and let it idle for five minutes.
    This is the manual way of ressetting the throttle this needs to be done when ever the battery is disconnected for a period of time. This can fix poor idling and hesitant acceleration. Let me know if this helps.
    full instructions here http://www.ross-tech.com/vag-com/cars/throttlebody.html
    A4 2.4 30V

 

 

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