HELP, 348 slow down light

Discussion in 'Technical Q&A' started by tclark, Aug 8, 2004.

  1. tclark

    tclark Formula Junior

    Jun 4, 2004
    Mechanicsburg, PA
    Full Name:
    Tom Clark
    I realize that there is tons of info on this subject. I want to see if
    anyone has experienced this.
    I just finished washing the car, 93 348. Did a pretty thorough job on
    the louvered engine cover, i.e. lots of water on engine.
    After drying the car off, I went to go for a short cruise. After warming the
    car up for about 5 minutes, I got in in to back out of the driveway.
    SLOW DOWN 1-4 light came on steady, not flashing. Car has no power
    and is idling very rough.
    Could this be due to water from washing? If not, I see where many of you have sugggested disconnecting the battery for 20 minutes in order to reset the ECU's. Can I simply use the battery disconnect
    switch under the hood above the front left tire, or do the battery cables
    actually need to be removed entirely from the battery?
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    RAYMAN Formula Junior

    Mar 10, 2004
    Full Name:
    Raymond Santilli
    Probably those pesky exhaust ECU's if that's the problem, it will not go away when the engine drys out. Most people just disconnect them, but you'll have no warning of cat overheating if you do.
  4. davey_jones

    davey_jones Formula Junior

    Sep 28, 2002
    wherever it's sunny
    Full Name:
    I washed the 348 the other day and covered the engine REAL GOOD with trash bags. I've seen these threads b4 and didn't want to take a chance..
  5. vincent355

    vincent355 F1 Veteran
    Rossa Subscribed

    Apr 8, 2003
    Wine Country
    Full Name:
    If you lost a bank there may be something going on other that just a pesky ecu. Try it tomorrow after it has dried a little more and report.
  6. tclark

    tclark Formula Junior

    Jun 4, 2004
    Mechanicsburg, PA
    Full Name:
    Tom Clark
    Last evening, (about 8 hours after the problem surfaced), the car started
    and ran fine. I had disconnected the battery for that length of time,
    and when I restarted the car, I let it idle without touching the gas for
    about 15 minutes, as prescribed in many posts.

    I went for a 30 minute drive, got everything good and warm, and drove
    with the revs fairly high at times. Everything seemed to be OK. Not
    sure what happened.
    I will definitely post any further developments, I know cars don't typically
    heal themselves.
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    RAYMAN Formula Junior

    Mar 10, 2004
    Full Name:
    Raymond Santilli
    All I know is it's just best not get Italian electronics/connectors wet, period.
  9. Husker

    Husker F1 Veteran
    Silver Subscribed

    Dec 31, 2003
    western hemisphere
    It's not the Italians' fault. The electronics and connectors are either German (Bosch), Japanese (NipponDenso), or American (Delco), depending on the year model.
  10. maserati424

    maserati424 Rookie

    Apr 11, 2004
    Berlin, Germany
    Full Name:
    frank gablenz
    I think a plug connector is getin wet and the plug isn`t firing.
    The fuel will injekted to the cylinder with no firing and goes to the catalysator and heat it ,up so the warning light goes on ,and shut down the whole bank
    After you washing the car ,blow out humidy and water with light airpressur from the ignition system , you won´t have these problems again, and the car must not heal itself by drying out in he garage.
  11. rkrenek

    rkrenek Formula Junior

    Aug 26, 2003
    Plano, TX
    Full Name:
    One of your ECU's is likely letting moisture inside via a small crack. Once wet, the affected sensor will malfunction & turn on. Once dried out, the sensor will function properly again & light will stay off.

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  13. roofguy

    roofguy Karting

    Dec 10, 2003
    Alamo, CA
    What will cause a slow down light to come on at 3500 rpm and go off at 3800 rpm. If you are to slow down, why does going faster do the same thing?

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