Blog scruz32

Sign in to follow this  
  • entry
    1
  • comment
    1
  • views
    1,417

1977 280z rpm tach gets stuck

Sign in to follow this  
scruz32

836 views

Hello I have a 1977 280z and the RPM needle gets stuck from time to time. when I park the car and leave it off over night it will reset back to zero. This is my first post so I don't know if I am explaining myself correctly. I am looking for some guidance of what steps I should take first to check it without having to dismantle the dash. I know there has to be someone else that may have or had this problem. Thank you and I hope I am posting this correctly. Open to some feed back.

Sign in to follow this  


1 Comment


Recommended Comments

Does the car run okay? Does the tach stick going both ways so that going to a higher RPM it still reads a lower RPM and when dropping off RPMs it stays reading too high? Just trying to understand better. From what I have read the tach can be taken out without dismantling the dash (harder with a dash cap). After turning off the motor does tapping the meter face cause it to drop to zero, which would indicate a mechanical failure instead of an electrical one? I would think replacing it would be a good road to take though I tend to be obsessive about fixing things even when replacement is easier (and sometimes cheaper!). I have never seen a circuit diagram of the inside of the tach though with that it might be possible to troubleshoot it if you have worked with circuits. Hopefully the mechanical bearings of the needle aren't sticking or it isn't binding to whatever coil drives the needle. If that is the case there might be a repair possible that would be similar to what is sometimes done with electrical meters to fix them. One suggestion I saw for electrical meters was to reduce the pressure on the bearings slightly in case they are binding. I did put ordinary light machine oil on the needle bearings on an electrical meter once and it started working but I think that stuff evaporates and gums up the works eventually. Anyone seen the inside of the tach meter movement? Does it just look like an ordinary meter as might be found in a VOM (volt ohm meter)?

Share this comment


Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Blog Statistics

    • Total Blogs
      168
    • Total Entries
      250
  • Blog Comments

    • I'm still waiting on a hoist to free up before I can start bolting the new brake parts on my Z, but I did make the drill jig today.  I started with a 12mm thick Mustang wheel spacer with a pilot.  I then made a drawing to layout the holes needed.  I transfered the drawing onto the spacer and I drilled three new 1/8" holes through the jig (spacer) so I'd have the correct 4x114.3mm holes.  One hole is shared from the original 5 lug rotor.  I then bolted the jig onto the Mustang rotor and simply dr
    • Local radiator repair shops used to be plentiful but getting harder to find.  Some of them just specialize in big truck-heavy equipment radiators.  I will be needing to do the same for my project.  I have heard good reports on gas tank RENU but there are none of those franchises in my area.  Good luck, John-Lugoff, SC
    • Decided to go with the 240sx conversion. Main reason is it’s strictly for the street and the parts were easy to source. What I didn’t realize was the 14” wheels won’t clear the caliper. Now looking for a set of 4 lug 15” rims and tires I can use during the build process. Can anyone recommend a temporary solution as far as make and model preferably a steel wheel that I can use until I’m ready to buy the wheel and tire combination at the end of the project? Thanks again for all the help out there.
    • There are several reasons to use the S197 rear brakes.  The rotors are larger diameter than the SVO rotors and they are vented.  The calipers have larger pistons to give them more power.  The big beef with the Maxima rears is that they don't offer as much stopping power as the stock drums.  The S197 rears allow the addition of an adjustable proportioning valve.  The Maxima rears cannot utilize an adjustable prop since the prop needs to be all the way open to get close to enough rear bias. 
    • Any particular reason to use S197 Mustang 5-lug brakes?  The Fox body SVO Mustangs had rear discs with 4-lug.  It's a popular swap to use SVO or T-bird Turbo Coupe rear brakes to retrofit discs to other Fox body Mustangs.  These parts are still pretty common (probably available as a kit).  Might be worth checking to see if they'll fit.