Tach Problem

[nealkeith]

The indicator needle on my Tach on my 74.5 260z kinda wanders around and pegs early. I have read some postings here and I am thoroughly confused. My car has an electronic distributor, and the coil has a resistor. Is this correct?

[EScanlon]

The resistor by the coil, was only used to reduce the voltage to the points to prevent their premature burning out.

If your car has been upgraded to an electronic distributor, it no longer needs that resistor, and in fact, may actually cause problems with your module.

2¢

E

[beandip]

If you are using a ZX electronic ignition , not only do you eliminate the resister but you need to use a different coil as well . I am using the stock ZX coil and find it is vary adequate. Gary

[nealkeith]

Yeah, that's what I thought. I believe I have the early electronic distributor, no module next to it.

[dzrt1st]

I have the same problems with the tach on my early 74 that I haven't figured out yet.

If your ignition is stock for 74 then you should have the resistor attached per Page EE-27 of the FSM to protect the "Transistor Ignition Unit". It describes your ignition system and its components. Attached is a pdf of that page.

Todd

EE-27.PDF

[240Z Racer]

Check the voltage regulator. I was told many years ago that if the Voltage Regulator does not keep the volts within a narrow range on 260Z's then the TACH would bounce all over the place. I never did test this theory, I put an aftermarket Tach with Shiftlite in instead. Hope this helps.

[nealkeith]

I can't open that pdf file. Do you have the direct link?

[dzrt1st]

Here's a scan of the page that you should be able to read.

Todd

[bpilati]

I get erratic tach performance only over very hot days. I'm surprised that no one has ever figured out what component is failing or malfunctioning. And I don't mean tell me that the tach is bad, I mean tell me what tiny component inside the tach is failing.