Welcome Guest! Please read more information about our club!

Just bought my first Z car (240), drinking from the firehose

April 28, 20204 yr

15 minutes ago, Captain Obvious said:

That said, however, I've not owned an early one either. I'm going off pics and documentation.

Like that can never be wrong...

By the time they got to anything I ever delved deep into, they had switched over to the newer voltage sensing tach. I believe that was 74.

I think the later 73 went to a three wire connector to the tach.

Link to comment

https://www.classiczcars.com/forums/topic/63904-just-bought-my-first-z-car-240-drinking-from-the-firehose/?&page=2#findComment-598182

Share on other sites

April 28, 20204 yr

comment_598186

13 minutes ago, 7tooZ said:

I think the later 73 went to a three wire connector to the tach.

This is how the wiring diagram looks for 73 in the tach area. The two ignition connections (from the ballast resistor and then back out to the tach) are the GW and BW wires. On the back of the tach (on the tach;'s side of the connector) those colors are the white with the red and black tape stripes):

So since they don't show the stub-off connectors between the gauges and the dash harness, (or any of the colors involved) it's hard to know for sure, but unless they pulled the ground signal through the metal tach case itself, then they ran four wires through the connector in that stub harness.

However, as previously mentioned, I've never been deep into anything earlier than 74, so I would obviously defer to someone who has! :excl:

Link to comment

https://www.classiczcars.com/forums/topic/63904-just-bought-my-first-z-car-240-drinking-from-the-firehose/?&page=2#findComment-598186

Share on other sites

April 28, 20204 yr

comment_598219

9 hours ago, 7tooZ said:

@grannyknot

were you running a stock distributor and ignition system? The earlier Z wire diagram would indicate that with the ignition key is in the run position there would be no power to the POS side of the coil. After market ignitions like Pertonix might change that. Just a thought.

Okay, the car was running a Pertronix with a bypassed ballast resistor and upgraded coil. @Dadsun sorry for the bad advice, I had forgot my car was modified.

Link to comment

https://www.classiczcars.com/forums/topic/63904-just-bought-my-first-z-car-240-drinking-from-the-firehose/?&page=2#findComment-598219

Share on other sites

April 28, 20204 yr

comment_598223

Yup. That'll do it. ^^

On a side note, I think the whole idea of running the primary ignition current into the passenger area and to the tach is a bad idea. I guess at the time that was the best they could come up with. They didn't ask me though. LOL

Link to comment

https://www.classiczcars.com/forums/topic/63904-just-bought-my-first-z-car-240-drinking-from-the-firehose/?&page=2#findComment-598223

Share on other sites

April 28, 20204 yr

Author

comment_598226

Thanks, everyone. I guess it's nice to know I've got a working tach running under the stock configuration, even if that configuration is a head scratcher. Glad to check it off my list because I've got a lot of other things to get to. I'll hopefully see y'all in other topic threads soon.

@7tooZ has pointed me to the Pertronix ignition to consider switching to. I figured most upgrades there would require switching to a signal-based 280z tach; nice to know there are options that will let me keep this stock tach.