Tach out, engine sluggish, what happened? | FerrariChat
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Tach out, engine sluggish, what happened?

Discussion in '308/328' started by surfdoc37, Sep 26, 2008.

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  1. surfdoc37

    surfdoc37 Karting

    Nov 19, 2004
    124
    St. Louis, MO
    Full Name:
    Mark M.
    #1 surfdoc37, Sep 26, 2008
    Three times in the last week I've gone for a drive, stopped somewhere, then restarted a still warm engine some 30 minutes later. On restart, the engine seemed sluggish, I checked the tach and it was out not showing anything. Each time after driving a short distance (i.e. a block) the tach came back on as the engine kind of suddenly spit and rev'ed about 1000 rpm, then seemed to run fine. Any idea what's going on here? My concern is I wasn't running one bank of the motor, but would this knock out the tach as well? (Speedometer was OK). Thanks for any advice.
     
  2. davebdave

    davebdave Formula 3
    Owner Silver Subscribed

    Mar 18, 2007
    2,381
    Northern VA
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    Dave W
    #2 davebdave, Sep 26, 2008
    crank sensor?
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Sep 26, 2008
    The tach signal on your MondialQV comes from just one of the Digiplex units. If you swap Digiplex units and:

    1. You still have the same problem (low power and tach dead), most likely something upstream like the crank sensor for that bank as Dave mentioned, or

    2. If you still lose power, but the tach now works OK, not a good sign for one of the Digiplex units.

    Of course, have you already check/done the improved grounding for the Digiplex units?
     
  4. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,523
    Canada
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    Newman
    #4 Newman, Sep 26, 2008
    Sluggish as in a 4 cylinder mondial when the tach doesnt work. My boxer didnt have too much steam when the fuse pump block melted for one of the pumps either, leaving me with 6 cylinders.
     
  5. Mike C

    Mike C F1 Veteran
    Lifetime Rossa Owner

    Aug 3, 2002
    6,081
    Southeast USA
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    Mike Charness
    #5 Mike C, Sep 28, 2008
    You'll find it is probably an intermittent fuse problem. Also, when the tachometer goes out, you're not necessarily running on 4 cylinders, but are running a defaulted minimal advance curve, which makes the car very sluggish.
     
  6. surfdoc37

    surfdoc37 Karting

    Nov 19, 2004
    124
    St. Louis, MO
    Full Name:
    Mark M.
    #6 surfdoc37, Oct 1, 2008

    Winner.
     

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