SL500 - cut out while driving, won't start

Discussion in 'Engine' started by boeken, Jul 15, 2017.

  1. boeken

    boeken Hardcore MB Enthusiast

    Feb 13, 2007
    R129 SL500 from 96

    on Tuesday evening in torrential rain my R129 lost all engine power, all the dash lights came on, power steering gone etc.

    i managed coast onto a country lane where i waited for next 6 hours till a recovery truck picked me up at 1am in the morning, fun!

    all electrics worked but just could not start it, the initial road recovery vehicle that turned up did not know what he was doing so I asked him if he could just order a recovery truck which he did.

    I found a thread that evening (nothing else to do) SL500 (R129) - Cut out & will not start - MBClub UK - Bringing together Mercedes Enthusiasts on this forum which described exactly the issue I was having (could not start but all electrics were working including alarm, immobiliser, all fuses were fine too)

    I did not have an allen key to open up the ODB port compartment, i did open it up this afternoon and the fuses were fine but once i had reseated the fuses the car started again! yeah.

    Does anyone know what these fuses are for (inside the ODB compartment_ and what could have possible caused it, the ODB port was not functioning.

    I think when i removed the red yellow fuse i heard something click inside under the engine cover, same for the red one.

    have not tried driving it too far, just round the block and all seems fine

    I did take this reading using my ODB reader, but to be honest I am not sure if this is because of my reader or whether there is indeed a real fault with the Fuel Sys1 and 2. I will take to the garage, there were no faults stored using my reader, the readings were take using live mode.

    Last 3 times it rained really hard I have had problems

    first time - speed sensor got wet and ended up in limp mode in Belgium driving back to UK
    second time- a coil went wrong, (nothing to do with the rain)
    this time - ???

    Attached Files:

  2. rorf

    rorf Hardcore MB Enthusiast

    Jul 23, 2011
    Cape Town, South Africa
    2000 SL320 v6, 2001 CLK320
    Definitely a moisture problem. I would remove and clean all fuses, check all earth points for corrosion and then ensure every electrical box and connection is water proof.

    Check your battery connections for corrosion too. Electrical spray works and dielectric grease can work wonders.
    1 person likes this.

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