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

1996 C280 sport missfire and alarm problems

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by Tim82, Oct 28, 2012.

  1. Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    Hello ,

    This is my first post so bear with me.

    My sisters 280 developed a miss fire , having dealt with a similar issue on this car before i replaced the coil pack controlling the cylinders that were missing.
    Long story short it turns out that the 12 vault supply wires to the coils were shorting out inside as all the insulation had cracked and degraded.
    During this time i had disconnected the battery as a friend had suggested this would reset the ECU.
    Now i cant test to see weather my quick fix on the wires has worked because on reconnecting the battery , the alarm wont dissarm.The remote central locking works fine but i dont get the usual beep and indicator flash to indicate the alarm has shut off.
    Battery is currently charging as i think my many hours of testing and engine cranking have drained it some what.

    Please if anyone can help me here i would appreciate it as my sister has my car while i fix hers.
    also is it possible to replace this section of the wiring loom that connects to the coils or is it time to get busy with the black tape.

    Thanks in advance
     
  2. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    Any one?

    Nearly 200 views and not one of you has an idea?
     
  3. MissyD

    MissyD Senior Member

    Messages:
    4,261
    Likes Received:
    98
    Joined:
    Mar 16, 2008
    sorry, you've not had a response Tim, hopefully one of the technical guys will be along soon.
     
  4. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    I hope so sarah im coming to the end of my patience with it.

    It seem the battery is at fault causing the alarm to remain armed but im still having problems curing the miss fire.After solving the insulation problem it is still running on only 4-5 cylinders.
     
  5. Cole@MBS

    Cole@MBS Forum Supporter Authorised Forum Supporter

    Messages:
    13,571
    Likes Received:
    652
    Joined:
    Dec 1, 2008
    Location:
    Hedge End, Southampton
    Your Mercedes:
    124 300 CE 24 Coupe, 209 240 CLK
    Hi Tim.
    Do you have the red and green lights in the mirror?? when you un-lock the car, what do the lights do???

    I found a good repair for the wiring is to slip the plugs apart and use heat shrink, this makes for a nicer repair........

    Just trying to remember the re-set method for the key, I am sure Malc will have it to hand..
     
  6. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    Hi cole@MBS

    I did have the lights yes , but i discovered the cause of my problem with the alarm was a faulty battery , with a charger connected i could arm and disarm the alarm all i wanted but as soon as i disconnected the charger it wouldnt work at all.
    With that solved i was able to continue testing and looking for the cause of the missfire.
    Still not solved it though , good strong switching signal on all 3 coil packs , all coil packs work , new plugs installed , head being scratched alot.
     
  7. kth286

    kth286 Senior Member

    Messages:
    3,067
    Likes Received:
    1
    Joined:
    Nov 4, 2002
    Your Mercedes:
    E320 Coupe 95
    is that the straight 6 (104 engine) ?
     
  8. television

    television Always remembered RIP

    Messages:
    164,074
    Likes Received:
    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    This must be the 111 engine for 96 I think , its possible that the ecu is fried if the wires were shorting
     
  9. bigasotonuk

    bigasotonuk Senior Member

    Messages:
    5,243
    Likes Received:
    9
    Joined:
    Nov 14, 2006
    Location:
    Southampton UK
    Your Mercedes:
    C43/55 AMG 1999 / C230K 1997
    I would suggest that its the straight six engine as the O/P mentions 3 coil packs also a 1996 202 was prefacelift, and the 112 V6 engine was,nt fitted till the facelift
     
  10. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    yes it is a straight six engine , im afraid i dont know alot about the car.
    What sort of cost is a new or replacement ECU
     
  11. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    also i cannot be exact with the age of the car as it had a personalized number plate , its been re registered since
     
  12. kth286

    kth286 Senior Member

    Messages:
    3,067
    Likes Received:
    1
    Joined:
    Nov 4, 2002
    Your Mercedes:
    E320 Coupe 95
    ok Tim

    It has got to be worth trying the following:

    Under each coil you have the extension pieces down to the plug.

    they do fail.

    inside each one is a 2k ohm resistor wire, which gets brittle due to the heat, and
    makes a bad connection.

    I would replace all three of those connection pieces - well I would be reading
    the fault codes first to determine which cylinders are not firing, but you
    may not have that facility - they cost approx £10 each from dealer (last time).

    Give full VIN to dealer parts person, or order online via Inchcape web site.
     
  13. OP
    Tim82

    Tim82 New Member

    Messages:
    7
    Likes Received:
    0
    Joined:
    Oct 28, 2012
    Location:
    Somerton , somerset
    Your Mercedes:
    1996 c280 sport
    Alarm problems are back and they brought along a faulty immobiliser with it.alarm has gone dead , wont arm or disarm and immobiliser wont turn off.
    Checked the coil extensions and they all are fine , good healthy spark from all three(tested on same feed)
    Entire wiring loom from coils replaced.
    Feel like im just going backwards with it now
     

Share This Page