240z tacho problem

[zr240]

Hi

I was wondering if anyone could help me with this tacho problem.

Its a std tacho on my 240z, It was working fine for ages and now when I start the car it only seems to be reading about half the amount of revs the car is doing. Sometimes after a while it will all of a sudden start working correctly but then when I turn of the car and re start it is inacurrate again.

any clues?

I have another tacho so I am probably going to change it to see if I have just got a dead tacho, just thought I would ask to see first

thanks

Ash

[Zs-ondabrain]

Most likely it's not dead, just in need of some t.l.c.

If you pull it, look for any loose connections both internal and external, most of the time the vibration from your Z will cause things to come loose

and the starting of the car can make the connection work and the next time the connection will jiggle loose,

something to think about b-4 you jump the gun.:classic:

Dave

[joedatsun]

I've had some of the same symtoms with my tach. Sometimes it works, other times it shows half of the actual RPMs. I'm going to pull it over the weekend to see what's loose (if anything).

[Ed]

My tach did the same. It slowly got worse, bouncing, reading 1k lower than actual. I ended up taking it out and taking it to a tach repair shop. $40.00 U.S. and it was fixed.

[Zs-ondabrain]

Hey Ed,

did they tell you what they fixed as a result of your $40.00

or did they tighten every thing up and charge you labor?

let me know and NO I'm not trying to be a smart-arse, I'm serious.

Thanks much,

Dave

[Ben]

Fair call....

I'd expect that between the dry joints & a leaky capacitor or two, it was stuffed!

Below are images of the internals of an early 260Z (inductive loop) tachometer:

[zr240]

Thanks for the help guys.

I am going to pull it out tommoror and try the other tacho I have. I will let you all know the result.

Thanks

Ash

[zr240]

Just to let you guys know I tried a different tacho and it works fine so there must have been a problem with the original

ash

[Ed]

It was a while ago but the guy told me he did have to replace something. Don't know what for sure. But it has been working fine since so I can't complain.