280zx alternator upgrade issue

[whamo]

I installed a 280zx alternator from a 83 2+2 in my 71 240z last summer. I used the conversion plug in place of the stock regulator. I recently noticed that upon startup the charge indicator shows a discharge until the engine is reved to at least 3500 rpm. Once that rpm is reached its like you flipped a switch and the alternator begins charging and actually charges very well,even at a low idle. However after I turn the car off and restart it once again shows a discharge until it is reved again. I have searched the internet and found this described on other alternator upgrades (GM 1-wire) but the "cut in" occurs at a much lower rpm. has anyone else experienced this on an alternator upgrade?

[Walter Moore]

It sounds like you missed one of the wires, perhaps the remote sense line? (I think it is a white wire.)

[whamo]

Ok, that must be the problem. I'll have to check those connections.

[tlorber]

Does anyone have input to this post? I just did the same upgrade to my '73 and had the same result. My "cut in" is around 3,000 rpm. Other than that it seems like a nice upgrade.

[Zs-ondabrain]

MSA told me that they had 6 customer returns on the ZXP and alternator upgrade they sell. I'm thinking it was a bad batch of Alternators. They said the customers complained of overnight Battery Drain. Their thought was that the ZXP was to blame.

I explained to them of the simplicity of a Jumper and a 1-amp Diode. The older ZXP's used Hot glue but tended to melt the glue out and onto the car when overheated under normal use. I have since been using a clear 5-minute Epoxy in place of the glue as it is rock hard and won't melt. The Thought again was that the Epoxy was shorting out the jumper to the diode. I explained the impossibility of the rock hard epozy transfering electricity.

I think that was the end of it as they ordered more ZXP's to bring their stock up.

I'm thinking alternator or bad wiring to the ZXP. My 70's wires were snapping when I moved the VR around. They were brittle and it was time to refresh them (cut them down and add the ZXP.

Dave

[steve91tt]

The Thought again was that the Epoxy was shorting out the jumper to the diode. I explained the impossibility of the rock hard epozy transfering electricity

Just FYI...

Epoxy is the green stuff in circuit boards so I agree cured epoxy won't conduct electricity. However, some epoxies, like JB weld, are pigmented with aluminum powder. These type may be slightly conductive.

[Inf]

The older ZXP's used Hot glue but tended to melt the glue out and onto the car when overheated under normal use. I have since been using a clear 5-minute Epoxy in place of the glue as it is rock hard and won't melt.

How long ago did you make the switch? I bought their kit earlier this year.

I assumed the plug material was hot glue, just from looking at it. What gets hot, anyway?

[tlorber]

In reading about alternators, it appears that they all have a cut in speed at some rpm. I don't know where in the process this occurs (i.e. voltage regulator?) but since everything else works fine, I'm inclined to think that the problem is NOT in the ZXP-at least in my case. If my cut in speed were around 1,000 rpm instead of 3,000 I would be fine.

I'll call auto zone to see if they have any input. I'm SURE they'll know.

[Zs-ondabrain]

Just FYI...

Epoxy is the green stuff in circuit boards so I agree cured epoxy won't conduct electricity. However, some epoxies, like JB weld, are pigmented with aluminum powder. These type may be slightly conductive.

Well that's kind of a given. But I use the clear (clowdy glass) 5-min. 2 part epoxy. It's much more pricey than the hot glue ($0.10 a 12" stick) as compared to the $4.00 for 0.84 oz. but I won't change the price due to a personal decision.

How long ago did you make the switch? I bought their kit earlier this year.

I assumed the plug material was hot glue, just from looking at it. What gets hot, anyway?

Very easy to tell which is which. The hot glue is punturable with your fingernail. The epoxy is almost glass hard and un-markable with your fingernail. I made the switch about 2 months ago.

In reading about alternators, it appears that they all have a cut in speed at some rpm. I don't know where in the process this occurs (i.e. voltage regulator?) but since everything else works fine, I'm inclined to think that the problem is NOT in the ZXP-at least in my case. If my cut in speed were around 1,000 rpm instead of 3,000 I would be fine.

I'll call auto zone to see if they have any input. I'm SURE they'll know.

Let us know what they say

[Zed Head]

In reading about alternators, it appears that they all have a cut in speed at some rpm. I don't know where in the process this occurs (i.e. voltage regulator?) but since everything else works fine, I'm inclined to think that the problem is NOT in the ZXP-at least in my case. If my cut in speed were around 1,000 rpm instead of 3,000 I would be fine.

I'll call auto zone to see if they have any input. I'm SURE they'll know.

I'm sure that Zs-ondabrain can explain in depth, but, as I understand the charging system, the L wire does what the "cut-in" speed is doing. I believe that it magnetizes the windings right away so that the alternator can start generating current immediately.

The L wire runs through the red charging light (Lamp) on your volt or ammeter. If the red light comes on when you turn the key on, and the other end of the wire is connected to the L terminal, then the windings are getting powered as they should. It goes off when the current starts flowing.

Does your red charging light work as it should. Lighted when the key is On, off when the engine starts?

I could be iffy on the details, but I'm sure that the red charging light is an integral part of the system and needs to be functional and wired correctly for the system to work as designed.

[Arne]

I'm sure that Zs-ondabrain can explain in depth, but, as I understand the charging system, the L wire does what the "cut-in" speed is doing. I believe that it magnetizes the windings right away so that the alternator can start generating current immediately.

The L wire runs through the red charging light (Lamp) on your volt or ammeter. If the red light comes on when you turn the key on, and the other end of the wire is connected to the L terminal, then the windings are getting powered as they should. It goes off when the current starts flowing.

Does your red charging light work as it should. Lighted when the key is On, off when the engine starts?

I could be iffy on the details, but I'm sure that the red charging light is an integral part of the system and needs to be functional and wired correctly for the system to work as designed.

No red idiot light for the charging system on a 240Z. Just the ammeter.

[Zs-ondabrain]

took the words outa my mouth Arne. He has a 70' 240Z. they didn't have Charge lights till much later on.

Nice thought though.

Dave