Zedyone_kenobi

Love this discussion. I am learning a LOT. As a mechanical engineer, I do not look at wiring diagrams hardly ever. So this is a great review of circuits. Z cars have so much to teach!

So, while the failure seems possibly diagnosed, lets talk about why. What makes the alternator stop charging if that diode burns out. I have been looking a LOT at a 72 wiring diagram (I do not have a nice color 71 Z wiring diagram). I am trying to find something that looks like a feedback loop with a sense input, internal regulation and finally, output happens. I assumed the white wire with the red stripe coming out of the back of the alternator was the output voltage back to the fusebox and battery respectively. Is the T connector used in the feedback loop which tells the alternator to 'activate'

I already have another MSA alternator kit coming from MSA as we speak. It will be here in a few days. When I was just SURE it was the alternator I ordered one. But now it may look like I have a spare. It will come with the bypass clip for the Voltage regulator and I will swap it out then. If I had a spare diode laying around I could just solder up one with clips, but I am pretty sure I do not have one.

Okay, I went into the electrical lab at work and borrowed a Fluke. with the Multimeter on Ohms, with the leads going red to black (left to right) on the two pins with the diode the Resistance is 23M Ohms with the leads going black to red (left to right) on the two pins with the diode the Resistance is 1 M Ohms I then switched the Multimeter to Diode Tester. Red to black or black to red the Multimeter read OL.

copy, that, I just read my new multimeter has a diode testor function. I will give it a go when I get home. Great Advice as usual SteveJ!

okay, there is a diode in there, now I need to see what it would mean if the diode was in fact bad, and what that failure would manifest it self as

interesting find. I checked the voltage regulator cap that you must install when you use an internally regulated Alternator. The 4 pins resistance was as follows. The two pins OL had a very dark patch on the back. I need to find out if there is a diode in there.

Now I have no idea what the test read, as it only comes back with a big green check. No voltage out put was displayed. According to the 72 Z wiring diagram the red/white wire runs back to the fusebox, so that seems like it should be supplying the car with power after the car starts. My problem is that the wiring diagram shows the voltage regulator and I am running an internally regulated alternator. So I have to figure our which wire it is that should be charging my battery and which is supplying the car with power (me thinks red'white)

The alternator tested a big green check at the parts store. However, I tried to test to find any out put from the T connector while the alternator was running well I got nothing, but it would see that it fried my volt meter LOL LOL. I am sure I should have measured the red/white wire from the back of the alternator instead. But now I have to get a fuse for my voltmeter or a brand new voltmeter... which would not be horrible.

Okay update All fuses are okay. One of the female spades in the "T" connector has 12.7 volts with the key off. The key in the Run position reads 11.8V but that also powering a electric fuel pump, so that is fine

Worry not my good man, your words of advice will not go unheeded. I will check out those parts this evening when I get home. A simple Alternator test is just one more part of the equation. It is simple and free.

I am currently running the MSA 60 amp alternator kit. It was purchased back in 2010. All my tests were at the battery. After I get the alternator tested, I will run the tests SteveJ mentioned. If the alternator comes back bad, then issue solved.

I pulled the alternator this morning (wearing my osha white safety socks - those who have followed my Z build will understand) and plan on taking it to get tested this afternoon. None of my connections were lose or corroded. No matter what I do the amperage never changes or moves with revs and the battery will NOT read more than 12.3 volts.

I will report back to what I am getting out of these wires later this evening. I will also double check the connections and clean all terminals carefully. I will inspect all wires for fraying and damage. I may have a spare MSA alternator in my parts bin. I could just swap that in to see if I get a different result. Car has never really had any real electrical issue since I purchased it in 2008. Had a light stalk issue once, but that turned out to be a bad connection that Dave helped me troubleshoot. Good times.

NO I have not done that yet. I will pull that plug and check the quality of those fittings this evening. Had to run to work this morning despite my need to fiddle with cars. What kinds of voltage signals should I be getting from those two wires?