R129 500 SL 1993 Engine Harness Replacement

Discussion in 'Electronics' started by dellyend1, Apr 12, 2014.

  1. dellyend1

    dellyend1 New Member

    Messages:
    2
    Joined:
    Feb 8, 2014
    Car:
    R129 SL 500
    Hi All,

    I've had an issue with a high stationary idle that is intermittent and only occurs when 500 sl has been running for over 1 1/2 hours and I've been researching root causes such as dodgy ACT or idle control. Anyway I have been poking around the engine bay and had a look at the MAF connection and to my horror the good old wiring was shot, disintegration of insulation etc.

    Well having read through loads of posts (many state side) I really do believe I need to bite the bullet and get the new wiring harness as it appears through reading, it is just a matter of time before things get worse and I could end up frying the ECU etc.

    So my key questions if I may (relating to the UK - South East) are :

    Are there any aftermarket harnesses that don't use the dodgy insulation or do I have to try and procure a post 96 harness ? If so is the harness different from a 93 model ?

    Who supplies any harnesses in the UK either Merc or aftermarket ?

    has anybody on this forum in the UK had theirs done ? If so could you let me know contact details.

    Tempted to try installing myself as it appears it is a case of tracing the old one pulling one plug at the time and plugging in new harness as you go. But what is the access to the loom like and do you need to dismantle much of the engine ancillaries ?

    Any idea of costs of indy garage to provide loom and install.

    Apologies for all the questions but trying to get all ducks in a row.

    Many Thanks

    Jeremy
     
  2. coupe deville

    coupe deville Hardcore MB Enthusiast

    Messages:
    786
    Joined:
    Aug 21, 2008
    Car:
    93 E320 coupe sportline facelift
    To be sure of the correct harness, the best way is dealer, using the vin. Expensive £700 ish. I bit the bullet about 5 years ago. You could have yours refurbed for about half the cost, you must have seen the posts when you did the search.
    Fitting was easy, I just started at the ecu, removed old plug (clamps are a bit tight ) and fitted new one, worked through it in an hour.
     
  3. E55BOF

    E55BOF Hardcore MB Enthusiast

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    Thread back from the dead...

    My new (to me) R129 still has the old crumbly engine harness. I'm too mean to fit a new one at £700 or so if it is possible to have the old one refurbished, but I can't find any posts about refurbishment on here. Can anyone point me in the right direction to get it done?
     
  4. Doodle

    Doodle Hardcore MB Enthusiast

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  5. E55BOF

    E55BOF Hardcore MB Enthusiast

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    Magic; thank you. It's all about knowing/guessing what terms to search on...

    Current MB price, £673 + VAT. I'll be calling Si-Leck soon.
     
  6. E55BOF

    E55BOF Hardcore MB Enthusiast

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    S211 E500, S212 E63, XK convertible, FJR1300, Caponord, Yamaha Bulldog
    I had assumed that the full engine harness needed replacement, but according to the auto-electrician who looked at it, it is the injector wiring loom that needs doing. Partial wiring harness from MB is £240, plus £80 labour, so might as well get it done before I collect the car.

    Whether that means the rest of the engine wiring harness has already been done, I don't know; and if not, how much it will cost. I'll find out in due course, no doubt...
     

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