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

1.8t with serious issues.. can anyone work this one out?

Discussion in 'A3/S3 Forum (8L Chassis)' started by WillJP, Nov 16, 2012.

  1. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    Right,

    my a3 started playing up, misfiring and running rich so brought it in at work and got this..

    20121110_155631.jpg

    says to me that the map sensor is shagged, plus boost leak, so in the process of fitting the fmic i fitted a new one. Then after a good bit of modifying trying to get the bumper back on lol i cleared the codes and fired it up but then got, map sensor signal too high, and got this on live data lol.. (engine is off)

    20121116_202157.jpg

    Ok so thought the map sensor was faulty but thought i'd check the wiring just in case and found a brake in one of the wires. Fixed the brake but still getting the same.. So unplugged the map sensor and ran live data with the engine off and it's still the same?!..

    Now i've either got the trace the wires back further to see if i find anything, the repair has messed with the signal, or the ecu is shagged??.. 1000 bar ffs! :think:

    Can anyone shed any light on the situation?
    #1
  2. Broken Byzan
    Online

    Broken Byzan Photographic Moderator Staff Member Moderator

    Joined:
    Apr 26, 2004
    Messages:
    12,584
    Likes Received:
    270
    The map sensor will show around a bar due to that being absolute pressure, anything the turbo generates is over and on top of that.

    Can't say I've ever seen a sensor too high before, the worst they do is max at 2550 mb.Were they the same sensor?
    #2
  3. Lewis583
    Online

    Lewis583 Active Member

    Joined:
    Mar 15, 2010
    Messages:
    877
    Likes Received:
    70
    It's not reading 1000BAR, it's reading ~1000mbar(milibar) which equals 1bar which is atmospheric pressure.

    If you look at Boost pressure cell in Live data you see how it reads 1400mbar, It reads this because you have unplugged the sensor so it is using a default reading. Plug the sensor back in and clear the codes and recheck the live data.

    How was the wiring repaired? Soldered or using crimp connectors? I always prefer soldering as you are certain to have a good repair.
    #3
  4. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    ahhh millibar! haha! it's been a long day lol we were stupidly puzzled awell! ha

    the wiring is soldered with heat shrink. so the wiring is actually ok then right?..

    Well the reading doesn't change even when plugged in and running but.. the map sensor isn't genuine so i'm thinking i've shooting my self in the foot on that one
    #4
  5. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    Nope, there's still a head ache! Lol I've checked the wiring from plug to ecu and they're fine. Tried it with a genuine map sensor and still the same, plus it still giving the same fault code even with it unplugged..

    Map/boost sensor signal too high

    Even went back to the standard map but still there so coming to the idea that the ecu has spiked some how..

    Next step to send the ecu off for repair?
    #5
  6. olethalb
    Offline

    olethalb Member

    Joined:
    Aug 29, 2012
    Messages:
    321
    Likes Received:
    45
    have you extended the map sensor loom with the same spec wire, thicker could cause more resistance.

    i'd recheck all connections and joins thouroughly, last time i saw this issue was a broken wire to the MAP sensor
    #6
  7. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    729
    Check all engine earths
    #7
  8. badger5
    Online

    badger5 www.badger5.co.uk Site Sponsor

    Joined:
    May 28, 2004
    Messages:
    7,297
    Likes Received:
    678
    maf sensor too high, too high map sensor signal.... whats the chances is the boost is going too high.... if not an electrical fault these faults could be teling it how it is

    the map sensor reads, you have ~1000mb for ign on no engine running..

    got access to a smoke tester? if so look for leaks and pipes from charge pipe to n75 to actuator...
    #8
  9. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    It's back to the standard map and its still there as a hard fault, even with the sensor unplugged, which of course mainly says it's wiring. I checked the wiring and found an old repair that had come apart again so fixed that.. I've checked the wires from the ecu plug to the map sensor plug with wiring diagrams and they are fine.

    I am down to either thinking that the repair is causing resistance in one wire or it's the ecu..

    may sound odd but would you say that if the 3 wires had a repair in the same place, it would give the wires the same resistance again?.. Just an idea because i feel literally drained with it all lol plus I'm getting fed up with walking!!
    #9
  10. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    729
    Checked for continuation right back to the ECU?
    Make sure the ECU is not swimming in water?

    What about unplug the ECU and check for corrosion on the pins?
    #10
  11. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    yea they are fine,

    haha yea i did think about it swinging in there but it was pretty dry and it was a wet day. the ecu and connectors are fine, just the little sliders it's sitting in is a little corroded
    #11
  12. WillJP
    Offline

    WillJP Member

    Joined:
    Dec 15, 2011
    Messages:
    38
    Likes Received:
    0
    Can anyone back me up on this?
    #12
  13. JUS3IN
    Online

    JUS3IN silver sleeper

    Joined:
    Mar 31, 2013
    Messages:
    819
    Likes Received:
    42
    i know have a map sensor high code... get to teh bottom of yours?
    #13

Share This Page