factory tach not working

Discussion in 'Troubleshooting & Diagnosis' started by granitecowboy, Dec 16, 2011.

  1. red78z

    red78z Veteran Member

    Sep 12, 2009
    check out gauge marks, daniel is a member here and has oil gauges for the clock position
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

    Feb 26, 2004
    Bloomington, MN
    An earlier tach will physically fit but the needle will be the wrong style.
    V6 & V8 tach are not interchangeable. They will function but they won't be accurate.
    (That's why I pointed out the red line difference. If you don't know this... Someone may sell you a V6 tach on ebay.)

    77RS (Daniel) sells oil pressure conversion kits exactly like you're looking for.
  3. 77RS

    77RS Veteran Member NastyZ28 Sponsor NazstyZ28 Sponsor Lifetime Gold Member

    Oct 18, 2006
    Asheboro, NC
    If the tach needle isn't moving (with engine running), it isn't gettting power. Most common problem is a loose ground. See pic below for ground connection. If the needle moves to 0 when powered up but isn't responding to revs, then it either isn't receiving a signal from the distributor or there is a problem with the internal circuit. The 78-81 tachs are totally different design than the 70-77 tach. The 78-81 tachs have a bicoil meter and will "float" when unpowered. The needle should return to 0 when powered up. The 70-77 tachs are weighted and should return to 0 when unpowered.

    I can repair/replace your tach if you aren't able to find the problem. As for the oil pressure gauge, no 2nd gen Camaro had an oil pressure gauge. I build an oil pressure gauge conversion from the clock that will look completely stock. Just let me know if you interested in the tach repair or an oil pressure gauge. I'll be glad to help.





    DMSTAINLESS Veteran Member

    Sep 19, 2010
    After reading ur post i tore into mine and found a buggered connection on the circuitry in the back. im so glad to get that aftermarket thing outta there!
  5. red78z

    red78z Veteran Member

    Sep 12, 2009
    i cant wait to get my cluster back in also , im doing the led string lights ,but in red:) And next year some time ill be doing the oil gauge switch
    Last edited: Dec 17, 2011
  6. granitecowboy

    granitecowboy New Member

    Dec 15, 2011
    milwaukee, wi
    Thanks to all of you for the help! When I rip into the dash Ill see what I can find. And Ill definitely be doinf the oil pressure gauge Daniel....Im just going to wait to see whats up with the tach so if I need you to fix or replace it I can order both gauges at once. That oil pressure gauge looks awesome. Why the hell didnt GM put one in from the factory?? Those stupid clocks never work....

    Thanks again everyone.
  7. Mean Green

    Mean Green Veteran Member

    Jul 12, 2010
    Pittsburgh, PA
    I was going though the NPD catalog and found a footnote with the replacement tachometers. Apparently, pre-1979 tach's are not compatible with HEI ignitions without a resistor installed. (This could be specific to their part I suppose)

    I, too, am having the tach issues - turn the key to on position and it blips to 1k, start the engine and nada!

    I need to take a close look at the needle length - I may have a pre-'79 tach and not realized it. Possibly need that resistor?

Share This Page