Hey All, jst a question about  wiring in the zx alternator upgrade. Have installed the alternator and adaptor from Dave, the car is charging but the Amp gauge fluctuates wildly when car is running. Does this look like the correct wiring for the alternator. Car is a 12/70 240Z.

Going out to change the oil, thanks in advance for any input!

Mark

All wires are secured properly, I snapped this pic before finishing install. ZX adapter is plugged in , impossible to install incorrectly. Gauge performed normally with old externally regulated alternator, only after new alternator was installed did gauge go wild. Immediately after tightening the belt, the gauge performed normally, but started to fluctuate intermittently during test drive, slowly but surely returning to a full time fluctuation. I will send Dave an email I guess. Thanks for the input.

33 minutes ago, northernz said:

Immediately after tightening the belt, the gauge performed normally, but started to fluctuate intermittently during test drive, slowly but surely returning to a full time fluctuation

That's a pretty good clue except for "fluctuation".  Can't tell if it's banging off the stops or jiittering 1 mm around the center.

If it definitely got better when you tightened the belt, I'd tighten the belt again and see if it gets better again.  I just made a comment based on average behavior but if your belt is oiled up or glazed maybe it is the cause.  No matter what though, it sounds like you need a new belt.  Get rid of that weakness and you'll know if it's the problem or not.

"it is worn and now slipping all the time."

The ammeter just shows charging or discharging, and rate of each.  So, adding numbers from the gauge to the description would help a lot.  And if the battery is fully charged or partially charged.  That will affect how much the belt slips.  So, just letting the battery drain down will make the problem worse.

Edited June 27, 20177 yr by Zed Head

I'm not entirely sure about what the external silver capacitor looking device on my ZX alternator is. I believe it has something to do with noise reduction. I don't see it attached to yours. Perhaps it is deleted for this application. I can post a picture of it when I get back to the car if you'd like.

 

 

I changed my vote.  Much depends on how fast the meter reacts, and how well damped the needle is, among other things.  I overlooked the basic "changed something and it got better" description.  That's the major clue, I think.

I agree that the belt seems to be the cause.When I say fluctuate, I mean it is going stop to stop as far as the needle can move! it is not possible to tighten the belt further , I sent Dave an email, we'll see what he says! I have to get to bed, work at 5 am! Will pick up  a new belt tomorrow, a cheap easy part to replace,

Thanks !

Quick update. Dave replied and I have the ground wire connected to the wrong spot. He also says a slipping belt will cause the gauge to fluctuate.Will correct these tomorrow!

I would not over tighten the belt, check the FSM for correct tension. A slipping belt may be due to a worn belt, or maybe contamination (oil) on it or the pulley. If you make it too tight you maybe stressing the water pump bearing. You don't want to do that.

When you say that the needle is going stop to stop as far as the needle can move, are you saying that it is slamming back and forth from like +40A to -40A?

If that's the case, then I doubt the problem is simply a loose belt. I'm thinking a loose electrical connection (shunt, fusible link, battery cable, something like that), or a faulty rebuilt alternator.

18 hours ago, northernz said:

Quick update. Dave replied and I have the ground wire connected to the wrong spot. He also says a slipping belt will cause the gauge to fluctuate.Will correct these tomorrow!

Ground wire was the way I was leaning.

From what I see in the pictures, the ground wire doesn't appear bolted to either of the threaded holes designated for that purpose by the big "E". Picture shows attached to a smaller bolt lower and to the right of that terminal. Not positive it matters. Outside frame of alternator is definitely grounded.


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Ground wire attached at correct point now, no change, going to replace the belt this afternoon, but I'm beginning to think it's something else. It's just that after I tightened the belt the first time, the gauge performed normally for a short drive before starting to fluctuate again, and is now fluctuating in a narrower range! It is hard to tell if the belt is slipping, it is a toothed belt not a v-belt and might be making a very slight squeal at idle , but the noise does not get worse when revs are increased. Belt for 19$ is a cheap place to start.

pop those plastic covers off the fuse links and make sure all is nice and tidy there as well.