Tach does not work... | FerrariChat

Tach does not work...

Discussion in '348/355' started by Dave rocks, Apr 15, 2013.

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  1. Dave rocks

    Dave rocks F1 World Champ
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    Nov 23, 2012
    16,047
    Orchard Park, NY
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    Dave Lelonek
    Hey Guys,

    So in doing my interior, I managed to mess up my tach. All I did was unplug the connector and it was working before - now it's dead.

    For those of you that have seen the connection - it's that plastic circuit board lead section that goes to the connector. Yesterday I tried 4 times to resolve it with no positive results - the last attempt was to clean the contacts of that plastic board with 400 grit sand paper.

    I'm going to pull out the whole cluster again so I can get a better look.

    Just posting here in hopes that someone has already gone thru this and knows the issue.

    Thanks in advance.
     
  2. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,613
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    The Bad Guy
    Did you check the fuses?
     
  3. Dave rocks

    Dave rocks F1 World Champ
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    Nov 23, 2012
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    Well, I looked at the manual and I see no fuse for the tach. This is a 1998 355 F1 GTS
     
  4. Dave rocks

    Dave rocks F1 World Champ
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    Nov 23, 2012
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    For the hell of it, I checked all fuses in the front compartment (all good). Today I'll check the ones under the passenger foot rest.

    I pulled the instrument cluster off again and check the integrity of the connection and it looks fine. I even pulled each pin out of the connector body (one at a time) to check the wire to pin integrity and that appeared good as well.

    Lastly, I put the car in auto mode and went for a ride and all was well so I know the ECU is getting the signal (RPM) from the motor. Clearly, the problem is the tach, connection or wires.

    Does anyone have information on the tach electronics and wires? (Signal/power)?
     
  5. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
    1,364
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    Paul Nicholasen
    Just to be sure, did you tap on the tach face sharply with your finger? I've seen a few cars where the tach needle just sticks for some reason and a good smack gets it going again. I would think with your removal of the pod etc. that it's been jiggled enough to be sure the needle is free, but didn't want to leave any stone unturned.
     
  6. taz355

    taz355 F1 Veteran
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    Feb 18, 2008
    6,007
    Indio Ca/ Alberta
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    Grant
    I had a similar problem with one of my super bikes and drug a magnet over the needle when it moved hooked it back up and it worked. I am not sure if the f tach has a coil though?
     
  7. Dave rocks

    Dave rocks F1 World Champ
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    Nov 23, 2012
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    After driving about 1800 miles with no tach, I decided to get back to this today.

    My mad-science electrical engineer buddy came over and we checked all the connections - all good.

    I pulled the tach out so I could access the front to move the needle by hand. When doing so I heard "snap".....I said "oh crap, I just broke the needle" nope, then I thought I broke the pin that holds it - that was good too.

    The sound was the needle breaking free from whatever had it stuck.

    It's back together and all is well - nice to have a working tach ;-)
     
  8. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
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    Paul Nicholasen
    Glad you got it working again, sounds like no amount of tapping would have fixed that one.
     
  9. Dave rocks

    Dave rocks F1 World Champ
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    Paul, I had tapped so hard I thought I broke my finger lol
     
  10. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    Well the was lucky. Glad to hear your tach is working.
     
  11. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
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    Paul Nicholasen
    Since you had it apart, I hope you put a dab of lube on the needle rest to prevent a recurrence...instead of the Crazy Glue you apparently used previously.
     
  12. Dave rocks

    Dave rocks F1 World Champ
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    I did not know how to remove the knob for adjusting the illumination so I could only reach my finger in enough to move the needle, so unfortunately I did not lube anything
     
  13. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
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    For future reference it just pulls straight out, as does the one on the speedo too.
     
  14. Dave rocks

    Dave rocks F1 World Champ
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    Thanks, I was nut sure if it was threaded or pressed, I pulled as hard as I had balls to..,
     
  15. PA Charles Ferrari F355

    Apr 3, 2010
    74
    Chester County
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    Charles B.
    I posted a similar issue of my tachometer having issues back on March 19th, 2013 and had 116 views with no replies. I stumbled on your advice of giving the tachometer a few love taps and now mine works! What made my dilemma unique was that it would no go beyond 30,000 rpms. I did not think the fix would have been so easy. I appreciated your incite on this thread that I stumbled across the other day.
     
  16. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
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    Paul Nicholasen
    To be honest, if your tach worked fine to 30,000 and stopped there, I'm not sure why the tap trick worked... it's usually only works if the needle won't move at all. That may explain lack of replies, it's an unusual story. Hope it continues doing what it's supposed to.
     
  17. PA Charles Ferrari F355

    Apr 3, 2010
    74
    Chester County
    Full Name:
    Charles B.
    But now thanks to your words of wisdom, and my tap, we now have this documented. If it gets stuck again, at least I know what to try first. I appreciated it.
     
  18. Extreme

    Extreme F1 Rookie

    May 26, 2010
    2,515
    Northern Utah
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    Erick
    Tapping with my finger is how I fix a good number of problems with the 355 if that doesn't work I use a hammer.

    seriously its good you got it fixed without spending a dime.
     
  19. PA Charles Ferrari F355

    Apr 3, 2010
    74
    Chester County
    Full Name:
    Charles B.
    I wish the finger tap procedure you described above would work for the other mechanical issues that I have had with my F355. Instead it was the finger tap on top of my checkbook before writing out the check. My sanity is truly those small victories and every time I get out on a drive.
     

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