What is the most common cause...

[Mat M]

...for the tach not working?

I have just resurrected my car after 12 years of sitting. In fact, I just got her registered yesterday and cannot wait to take her out again when it's not raining.

All of the guages work well (I haven't really checked the clock) but the tach doesn't do a thing. I am thinking that maybe a connection is loose, or not attached, when I got the thing there were a LOT of disconnected looms.

Any/all comments/help would be greatly appreciated! Thanks!

[Arne]

It is my understanding that if the tach on a 240Z was unplugged that the engine won't run. So it's probably not something as simple as the tach being unplugged.

What ignition do you have in the car?

[EScanlon]

Mat:

From your signature, I figure we're talking about your 71, and Arne is right on with the tach/ignition connection. If your tach isn't IN the circuit, the engine won't run.....EXCEPT..... you CAN hook it up backwards. In that case the engine will run, but the tach won't work.

Have you done ANYTHING to the distributor / resistor / coil connections at the front of the car? What about upgrading the car to the electronic distributor from the ZX?

You don't mention IF the car runs at all. You just say you resurrected it. Does the tach do ANYTHING? What about small spikes when you're starting, or while the engine is running (if it's running)? Anyone of those would help diagnose and suggest.

In the meantime, I'll stick with the old standby: "Check all the connections you did or may have disconnected."

Enrique

[Mat M]

Man, I thought I was being thurough in my explanation, you guys are good with bringing up questions.

You are correct, it is my 71, and it IS running, and yes, I have changed the original dizzy with the ZX and the e12-80 module. See, I am such a newbie that I wasn't aware that the tach and dizzy were related. I thought the tach was like the speedo with a sensor at the crank, or something...

Now that you have asked me those Qs, there is a loose wire from the loom with the wires that attach to the coil that comes from the passenger side...

[edit] no, I haven't noticed any spikes or play with the tach's needle at all

[Arne]

If there is an extra black wire near the coil that isn't connected to anything, it should connect to the negative terminal of the coil.

The picture below is on Bryan Little's site:

[Mat M]

If there is an extra black wire near the coil that isn't connected to anything, it should connect to the negative terminal of the coil.

Arne, did you know your reputation, to me, has been increasing with leaps and bounds since I have been lurking on this site?

You are now nearing Z GOD-like status!

Thanks, I will try connecting that wire when I get home from work.

[Arne]

You are now nearing Z GOD-like status!

Now if only my Z God status could enable me to materialize new parts....

[Mat M]

Now if only my Z God status could enable me to materialize new parts....

Hey, I got a BUNCH of recylced parts, what are you looking for?

[Arne]

It's not so much that parts are hard to find (for the most part they're not), but that the money to buy them with is in short supply!

[Mat M]

It's not so much that parts are hard to find (for the most part they're not), but that the money to buy them with is in short supply!

I am with you. I find that I have to sell parts that I don't need at the moment in order to afford the ones I do!

[EScanlon]

Arne: The diagram you posted will only work IF he has a later style Tachometer and not the earlier style.

I'll have a longer reply for the Early Tach (Loop Circuitry) vs the single wire Tach, Later Style (Inductive Circuitry) in a bit, just wrapping it up.

Enrique

[Arne]

Arne: The diagram you posted will only work IF he has a later style Tachometer and not the earlier style.

Far be it from me to disagree, but I'm pretty certain that the above diagram is how I did mine, with the original tach. Works fine, as far as I can tell. I'll have to wait until the weekend to verify, however.