Tach reads 50% | FerrariChat

Tach reads 50%

Discussion in '308/328' started by Glen_Lloyd, Sep 11, 2014.

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  1. Glen_Lloyd

    Glen_Lloyd Formula Junior Owner

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    Lloydminster AB
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    Glen
    Tachometer appears to only read 1/2 the RPM's. Any quick or easy fix? On odd occasion it appears to read correct so I am thinking it might be a poor connection somewhere?

    BTW 1987 328
     
    Last edited: Sep 11, 2014
    Glen_Lloyd, Sep 11, 2014
    #1
  2. AJS328

    AJS328 F1 Veteran Owner

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    Augustine Staino
    Happened to me on my current car a couple years back. It needed to be sent out to be fixed. North Hollywood Speedometer, if I recall correctly.
     
    AJS328, Sep 11, 2014
    #2
  3. Crallscars

    Crallscars F1 Rookie

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    Douglas Crall
    By chance did your mileage go up by 100% ?
     
    Crallscars, Sep 11, 2014
    #3
  4. Hannibal308

    Hannibal308 F1 Veteran

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    Mine reads 200% or more after the car is warmed up. I haven't gotten around to trouble shooting it yet but from several threads about errant tachs, it can be a distributor/ignition system issue and have nothing to do with the tach. Just putting that on your list of things to look into. Would really suck to spend big bucks on a tach refurb and have it come home doing the same as before.

    Best!

    Hannibal
     
    Hannibal308, Sep 11, 2014
    #4
  5. thecarreaper

    thecarreaper F1 World Champ Silver Subscribed

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    First thing to do is clean the connections for the tach on the left rear rail by the two coils. I think there is a thread with pics. Next is swapping the digiplex connections to see if it changes the readings. +1 for N. Hollywood Speedo.
     
    thecarreaper, Sep 11, 2014
    #5
  6. 4skin

    4skin Rookie

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    Does anyone know if this looks right? I just got a 1986 fully restored 328GTS. The car looks great. When I purchased the car the tach was sluggish. It was sent out to be repaired in Palo Alto. When I got it back it still seems slow. From the sound of the engine it sounds like the revs should be much higher but it only goes to about 2500 rpms. Any advice?https://vimeo.com/116579948
    What do you guys think? Am I crazy?


    Sent from my iPhone using Tapatalk
     
    4skin, Jan 12, 2015
    #6
  7. jmaz

    jmaz Formula Junior

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    The tach on my '89 328 was acting similar to this after I'd first bought the car, but with more frequent driving than was done by the previous owner, the problem showed up less and less.

    Interestingly, since spark plug wires and extenders were replaced as part of major servicing, the behavior hasn't shown up at all (fingers tightly crossed...). That could just be a coincidence, but I wonder if there's some way that the ignition system electrics would affect the tach. Doesn't seem like it, but maybe some sort of electromagnetic interference could come into play.
     
    jmaz, Jan 12, 2015
    #7
  8. Rich S

    Rich S Formula Junior

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    Rich Saylor
    See the other thread on this topic, very close to this one.

    Cheers,
    Rich
     
    Rich S, Jan 13, 2015
    #8

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