1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

B7 s4 cranks but won't start

Weyroc Jan 22, 2015

  1. Weyroc

    Weyroc New Member

    8
    1
    3
    In need of some help... I have a starting issue with my 07 S4. The car cranks strong but won't start. The TC, red battery, EPC, check engine(electrical), and ABS lights all come on. I had it in the shop, fault codes were no spark/ they "cleaned" coil pack connections and cleared the codes and the car started. Ran the car for about a month with several no starts. Let the car sit for a day and it would start. They also ruled out positioning sensors, fuel pump and changed the fuel pump relay... plugs are new. No rattle at start, car has 74k. Any help? Or similar issues?
     
  2. Avatar

    Google AdSense Advertisement


  3. Crank sensor
     
  4. Weyroc

    Weyroc New Member

    8
    1
    3
    That's what I thought too. However the shop tested it and they didn't seam to think that was the issue. Would a failure in a coil pack cause the no start?
     
  5. Av4nt

    Av4nt Well-Known Member Team V10 Team Sprint saloon Audi S6 quattro S tronic

    1,505
    379
    83
    Dont B7 S4's suffer from starter issues from time to time. im sure I read this somewhere as a common fault....
     
  6. Weyroc

    Weyroc New Member

    8
    1
    3
    I haven't heard that. The car cranks over strong. I'm going to get into it on Sunday and pull the crank sensor. Probably going to go ahead and replace the coil packs as well. The problem is completely intermittent. When the car starts it runs strong, no misses, Ect. I'm also going to change the ECM relay and check the two 15amp fuses. The fault codes were no spark codes so I'm leaning towards coil packs. My question is, would that cause a no-start of one of the packs was bad? Or would it still start and just run rough?
     
  7. Weyroc

    Weyroc New Member

    8
    1
    3
    Love the car but I'm getting rid of it. Need something bigger for the fam...
     

    Attached Files:

  8. SDHA4SLine

    SDHA4SLine Well-Known Member Team Silver Audi Avant Owner Group S-line owners group

    2,617
    523
    113
    If you do don't get an Avant as the rear leg room is appalling unless the two people in front seats are less than five foot tall
     
    Weyroc likes this.
  9. Av4nt

    Av4nt Well-Known Member Team V10 Team Sprint saloon Audi S6 quattro S tronic

    1,505
    379
    83
    im pretty sure that it would just run rough if it was a coilpack and not cause it to mis-start. doesnt sound like coils to me, i could be wrong. Wait for Dualmono he should know hes an S4 guru!
     
  10. OxfordRich

    OxfordRich Collecting Rings VCDS Map User

    114
    10
    18
    Post exact codes and don't forget coolant temperature sensor's dodgey values can prevent starting.
     
  11. Weyroc

    Weyroc New Member

    8
    1
    3
    I don't have the paper with me but the code read "no spark at ignition coil" there were 7 of them. No other codes were present.
     

    Attached Files:

  12. Avatar

    Google AdSense Advertisement


  13. Weyroc

    Weyroc New Member

    8
    1
    3
    Alright! I figured it out... I changed the crank sensor, which was pretty straight forward. Contrary to a few how-to posts I've seen, you don't need to pull the cat to get to it from underneath. Take the coolant resivor off and tie it back over the engine. Remove the cam sensor plug and pull out of the way. Follow the crank sensor wire (grey plug) from the plug bank behind the coolant resivor down to the sensor. It's a one handed, by feel only job, but it can be done. Use a T30 torx on a micro ratchet, I also used a handheld L T30 to get the initial break. Remove/ replace. Right hand to get it off, left hand to put back on. HOWEVER the sensor wasn't the issue. It ended up being the #614 70 amp ignition relay in the ECM compartment. Pull the cover and take the clip off the ECM, there are 4 relays. I found it by tapping on it and then the car started. Hope this may help others. The relay was 23.00 at auto zone and was a factory replacement Audi/VW brand. Got the sensor online for 40.00, not the 125.00 all the parts stores were charging.
     
  14. leegsi

    leegsi Active Member

    489
    57
    28
    Thanks for the update and to think it was so simple to fix in the end
     
  15. kev1973

    kev1973 New Member

    18
    1
    3
    Ive had the same problem, no glow plug light was the give away that it wasn't going to start, mine was intermittent. I swapped that relay too and mine seems to be cured.
     
  16. Ed_B7_S4

    Ed_B7_S4 New Member

    1
    0
    1
    Thanks for this post!

    It helped potentially solve my issue. For the past month my car would only crank until I would get a jump or charge the battery over night. It would eventually go back to just cranking in as short as 4 hours. Tried starting it one last time after the car sat for 2 days without charging the battery before I checked out the ignition relay. I found that it was really loose and couldn't get it out, like it was fused to its connectors. Regardless of its condition, i tried to start the car after a minute of playing with it and IT STARTED RIGHT UP!!! For the past few days there have been no starting issues since and I still have not charged the battery. Must have been how the ignition relay was positioned. Talking to my mechanic, the ignition relay can overheat and can fuse to the connectors, most likely causing some sort of interrupt. I am having the connection and relay replaced to hopefully fully fix the issue.
     
  17. Nollywood

    Nollywood B7 420-R Avant Team Dakota Team V8 Audi RS6 Audi A4 Audi Avant Owner Group quattro Manual

    684
    200
    43
    Bad crank sensor, or flywheel TDC reference pin.

    Don’t rule this out, just because a shop said so, or just because crank sensor DTC wasn’t pulled in a scan.
     

Share This Page