456 struggling to start, then irregular revs, eventually cutting out…? | FerrariChat

456 struggling to start, then irregular revs, eventually cutting out…?

Discussion in '456/550/575' started by MarcUK, Sep 10, 2022.

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  1. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #1 MarcUK, Sep 10, 2022
    Hopefully someone might be able to help, please?

    I have taken the leap into older Ferrari ownership, so to join the 488, I have just added a 1994 456GT manual in Blu Le Mans over Crema.

    However, I have my first issue!!! It struggled to start. Once ticking over it struggled to maintain regular revs at idle and eventually cut out. Battery pack engaged and rev problem resolved. Drive off and I find myself with the revs irregular and having to keep rev-ing it out of gear in traffic to stop it cutting out…

    I replaced the battery and the problem appeared to disappear. Battery cut off engaged after a 100 mile drive and I went sleep happy. Next morning it struggled to start again and the revs were irregular again!

    Has anyone experienced this? What was the problem? I am booking it in to have it looked at but concerned it won’t make the 20 miles!
     
  2. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #2 Qavion, Sep 10, 2022
    If you use the battery cutoff switch, you are probably erasing the engine management system "learned" parameters (including idle control data), especially if you have a 2.7 Motronic ECU.

    To get the system to relearn, it's important to start the engine and let it get to operating temperature (about 10 minutes) without pushing the accelerator pedal. The AC must be turned off and no additional electrical loads present (headlights, etc).

    Is there a reason you're using the battery cutoff switch and not fitting a trickle charger?

    Of course, there may be other issues, but one step at a time ;)
     
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  3. 308 GTB

    308 GTB F1 World Champ
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    #3 308 GTB, Sep 10, 2022
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  4. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #4 Qavion, Sep 10, 2022
    The confusing part for me is the "steady state water temperature". Do you let the car warm up first, then wait 10 minutes?
     
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  5. 308 GTB

    308 GTB F1 World Champ
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    #5 308 GTB, Sep 10, 2022
    Ian, I've interpreted it to mean that once the car reaches "steady state water temperature," to let the car idle for at least 10 minutes under the 4 conditions specified. This is what's done every morning at the track when my F355 Challenge, also Motronic 2.7, is left overnight in the garage with the battery cut off.
     
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  6. tazandjan

    tazandjan Three Time F1 World Champ
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    Jul 19, 2008
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    Terry H Phillips
    #6 tazandjan, Sep 10, 2022
    Try this, gleaned from several WSMs, and stop using the cut-off switch routinely:


    Run cycle.

    Turn battery disconnect switch off and turn off all accessories (stereo, A/C, etc).


    Let engine get completely cold or wait at least 30 minutes.


    Reconnect disconnect switch.


    Disarm immobilizer with the fob (not required for 94 456 GT/ Motronic 2.7).


    Insert key in ignition and leave for 30 seconds.


    Turn ignition to on and leave for 30 seconds.


    Turn ignition off and leave for 30 seconds.


    Turn ignition on, wait for Check OK, and start. May have to push fob again if 120 seconds have elapsed since last fob actuation (not with Motronic 2.7).


    Let idle with no input whatsoever for 10 minutes.


    Turn accessories back on and drive gently for 10-15 minutes at least.


    You will have to insert stereo code, if required.
     
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  7. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #7 MarcUK, Sep 11, 2022
    Thank you all very much! I will desist from using the cut off switch and get a trickle charger (my 488 and AM V8 have one) The reason I was using the cut off switch was because I assumed there was a drain (hence the new battery requirement) and I haven’t bought and connected a trickle charger yet!

    I will try your suggestions today and keep you posted! Thanks again.
     
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  8. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #8 MarcUK, Sep 11, 2022
    Update:
    It would seem that following your simple start up and idle for 10mins seems to have resolved the problem.

    I have connected a trickle charger rather than use the cut off switch, so hopefully that will be the end of that!

    Thank you so much for all contributors who helped me out!
    Marc
     
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  9. MarcUK

    MarcUK Rookie

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    #9 MarcUK, Sep 11, 2022
    tantumaude, paulchua, 308 GTB and 1 other person like this.
  10. 308 GTB

    308 GTB F1 World Champ
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    #10 308 GTB, Sep 11, 2022
    Nice cars!

    Happy to help, Marc.

    Barry
     
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  11. tazandjan

    tazandjan Three Time F1 World Champ
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    #11 tazandjan, Sep 11, 2022
    Very pretty 456 Marc. The red car looks nice, too.
     
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  12. paulchua

    paulchua Cat Herder
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    Jul 1, 2013
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    #12 paulchua, Sep 12, 2022
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  13. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #13 MarcUK, Sep 12, 2022
    Many thanks…I just don’t get out in it often enough. Probably like most of us!


    Sent from my iPhone using FerrariChat
     
  14. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #14 MarcUK, Sep 12, 2022
    Thank you very much, sir!


    Sent from my iPhone using FerrariChat
     
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  15. fastwilly

    fastwilly Rookie

    Aug 26, 2022
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    Liverpool UK
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    Will Chambers
    #15 fastwilly, Sep 12, 2022
    Do you still have a drain on the battery? If so ratarossa and the gentleman that owned my 456 prior to me identified the stereo as the problem, ratarossa did a video on how to assess if it is causing the drain and how to resolve it. The previous owner of my car just replaced and updated the sound system and made it blue tooth.
     
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  16. MarcUK

    MarcUK Rookie

    Dec 19, 2020
    17
    UK - South East
    #16 MarcUK, Sep 13, 2022
    Thank you. I will check that out. Do you know if the previous owner did a DIY replacement or who they used? What is the name of your system, please?
     

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