Electrical nightmare... again

[a7dz]

I am with E check the connections. The ground for the alternator is on the fender well just below the battery take it off sand the terminal and run a tap through the threads replace the screw and washers. Do the same to the wires at the alternator. Check the wire for contiuntiunty from the ground point to the alternator. These are know to over heat and then corrode giving you the problems you are having. I just replaced the gound wire in my 70. It was melted the first foot from the alternator, and at least half of the wire strainds were broken.

[EScanlon]

The '73 does not have fuseable links.

Excuse me, but that's not true.

Even the earliest Z's had at least ONE fusible link. That one link is from the Starter to the wiring harness. If you blow that one it disconnects the complete electrical system of the car....completely and thoroughly. It's the main connection for the Positive terminal of the battery to the fuse box. Disconnect this and even the clock won't work.

Later Z's gained more fusible links as the electrical system grew in complexity with Seat Belt Buzzers and Starter Interlocks etc. Eventually, these were located in a central box on the firewall.

With the blurred definition of model changes through the years it is very difficult to ascertain exactly at what number VIN changes were in fact done. Even with the best of records, 30+ years of maintenance and repairs can lead to a very fuzzy definition of what a car should and could have.

2¢

E

[JimmyZ]

Just an obvious 2c observation. When I completely stripped my car I found that the harness had rubbed through the insulation in a couple spots. The rubber grommets had rotted and allowed things to start shorting a bit. (Firewall and radiator support grommets) I also had the power drain problem which was somehow fixed when swapping fuseboxes and/or patching the harness. Still can't fugure that one out. At least it's OK now:)

FWIW

Jim

[rewiredz]

quick question, is there a charge light on the ammeter(gauge)? there needs to be a drop of voltage on one side of the regulator for it to start the alternator charging. at least thats how they have it set up on the 280z's. not sure how different the entire charging system is. if they use some sort of resistor on one side of the regulator, might be worth checking out. maybe someone else here will have a better explanation on how to check this on a 240z.

also maybe check to make sure your alternator is grounded properly, sometimes they get grime and stuff in the mounts and don't make contact with the engine block/ground. i think they also ran a wire out of the alternator to a ground just as a redundancy. again, this might be different for 240z's, but im assuming the basic principles are the same.

[holtyrd]

Thank you all for your responses they steared me in the right direction. Turns out, one of the tach wires I had replaced recently was the culprit and it by-passed an important piece of the alternator sensing line. My inexperience definately showing through on that one.

/thanks again,

Rich

[Ramses]

Thanks for the corrections E. Oops.