Advice Needed: RPM Gauge Not Working | FerrariChat
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Advice Needed: RPM Gauge Not Working

Discussion in '308/328' started by Joe_CT, Jan 3, 2009.

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  1. Joe_CT

    Joe_CT Formula 3
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    May 16, 2007
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    #1 Joe_CT, Jan 3, 2009
    I am a little perplexed. I just finished up replacing the antifreeze and coolant hoses on my '85 308 and started the car up to bleed the system and let the engine run for a while. I noticed the RPM gauge was not working (and car was running rough, but I don't think they are connected). The RPM gauge was working the last time I had the car out about two weeks ago. Does anyone know where to start in trying to diagnose this issue? I am not even sure where to start.

    Any advice would be greatly appreciated.
     
  2. hardtop

    hardtop F1 World Champ

    Jan 31, 2002
    11,292
    Colorado
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    #2 hardtop, Jan 3, 2009
    The tach sensor runs off of one of the ECU's. The connection may have come loose which would also cause rough running. Your owners manual has a schematic. That would be the first place I would check.

    Dave
     
  3. Joe_CT

    Joe_CT Formula 3
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    #3 Joe_CT, Jan 3, 2009
    Dave,

    Thanks. I found the schematic in the manual, but didn't really help me too much. Two quick follow up questions (I know they are dumb)... where are the ECU's and do you have any idea where the RPM counter sensor goes into the engine (so I can either follow the line from the ECU to find it directly on the motor)?

    Thanks again, Joe
     
  4. irondogmike

    irondogmike F1 Rookie

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    #4 irondogmike, Jan 3, 2009
    in the boot section,you have to take the carpet out first then,it should be on the left side of the car
     
  5. Joe_CT

    Joe_CT Formula 3
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    #5 Joe_CT, Jan 3, 2009
    Thanks Dave and Mike. I was able to diagnose the problem with your help. It appears when I was replacing the coolant hose under the rear bank distributor cap, I must have snagged the RPM sensor connector under there and disconnected it. I used the info from you guys to find an old post that had a picture of the location of the RPM and TDC sensors. I caught out of the corner of my eye a connector that was not attached to anything (light hit it jsut right after about 10 min looking for it). I was able to get it reconnected and the RPM gauge started working again and the engine was back to its old self.

    Thanks for the assistence!!! It is always appreciated.
     
  6. irondogmike

    irondogmike F1 Rookie

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    #6 irondogmike, Jan 3, 2009
    now get out there and drive that beast,its a nice day
     
  7. oliv928

    oliv928 Karting

    Aug 14, 2008
    171
    France, Toulouse
    #7 oliv928, Jan 6, 2009
    hello,
    my RPM meter is "strangely" bad working. At low RPM it seems to work, but when engine is runing faster, the RPM meter stay at about 1200RPM. Do anyone know where it could come from, and how I can try to diagnoze myself ?
    Happy new Year,
     
  8. Joe_CT

    Joe_CT Formula 3
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    #8 Joe_CT, Jan 6, 2009
    Start by making sure all your RPM & TDC sensors are connected properly. Here is a post that I used to find where they were. Last post has a good picture. Good luck. Joe

    http://www.ferrarichat.com/forum/showthread.php?t=74902&highlight=%22308%22+%22rpm%22+%22sensor%22
     

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