Amp gauge pegs to the + side

[Datrock]

Hi everyone, the car I'm working on has been off the road for years, I put in a modular volt regulater and a used altenator on the 1600 engine sitting in a 70 srl.

I have been tinkering with the engine while it's running. I finally hooked the charging sytem up and I notice my amp gauge goes to the positive side and fluctuates with the rpm's of the engine. I rev up the engine and the gauge pegs to the + side. I have no fuses in at this time or at least until I find out this problem. Plus the engine is properly grounded.
Before I tackle this charging issue I thought I would run it by the list just to see if it's happened to anyone else and what the solution was. Thanks ahead of time... Bill

[spl310]

I would suspect that the regulator is not regulating...

[Datrock]

Hi Sid, I tried another voltage regulator and the problem continued. One thing I did notice and kinda sidetracked me was the altenator has 4 wires coming out of it going to the plug and the wire harness has 3 wires going to the plug,Field(WB), Nuetral(Y),and Earth(B). Alt(W)should be the fourth wire like on my 68.

But since this is a 70 it is different. After looking at a wiiring diagram there was a change to the 4 wire starter harness and that 4th wire is the "A" white wire that would go to the altenator on a 68 0r early 69.

I need to do some contact cleaning too!

I did check the field and it was about 6-7 volts and the output "A"(W) was about 12-13 volts and both climbed a volt or 2 at the regulator while reving the engine. Tomorrow I'll takeoff where I left, at the altenator, maybe stick some fuzes back in and put a load on the charging system and see what happens.... Bill

[spl310]

Bill,

Is the alternator a Roadster unit? I have not checked the wires on the ones that I have, but I suspect that something is awry wiring wise if you have 4 wires going out, but only 3 into the harness. I could be all wet though...

[Datrock]

Hi Sid...All wet, is it raining there too? I think the wiring harness is correct. I read Datsun did some changes around srl10,000, which changed the starter harness to except the "A" wire I'm missing at the alt plug.

The alt. is one I used before on my 68 spl. It could be bad, that might be why it was on the shelf. I just picked the cleanest one that spun...

In the early 80's I belonged to the roadster club out of Portland, Or and I got monthly news letters and the alt to reg relationship is desrcibed in depth in one issue. It tells about the field and nuetral voltages and the Alt output. But one thing, it show 4 wires in the harness going from reg to alt.???

If you look at the wiring diagram for the later model dual bank fuse cars it show the change from the single bank cars. Look at the starter connections and alt. you'll see the differance...

There are quite a few little changes on the 70 model that I was not aware of...Thanks again Bill

PS..I guess I need someone with a 70 srl to look at the alt plug in their car and see if there are 4 vs. 3 wires in the connection...

[Datrock]

Well I may have made some progress, I tried a third regulator, a modular one, and the amp gauge does not go way to the right upon revving the engine. It now flickers on the positive side while idleling. When I rev up, it does not bury itself to the positive side of gauge. Not sure if it's fixed but it is acting different.... Bill

[spl310]

Bill,

That is great! Perhaps you are exorcising the gremlins after all!!

[Linda]

Thread revival.
Had this issue recently also. The stock alternator is rebuilt from a few months ago, and new voltage regulator at the same time. So it was puzzling that the amp guage would show a large positive charge, when it had been working fine. I used the lights on to bring it down but it was still higher than it was supposed to be. All grounds were checked and looked good.
After cleaning the starter harness on both ends, and the connector plug, the amp guage is where it should be, just slightly over 0 . Another thing to check.

Linda

[K1200 GT]

Hi Linda,

That was in 2005, hope Bill got er fixed by now......

Richard

[EScanlon]

I think she was posting for future readers, that's why she said... Thread Revival.

At ClassicZCars we've got the problem where everybody feels that their experience merits a whole new thread, and they don't search nor add to an existing thread. Makes for HOURS of sifting trying to find that ONE bit of information to get back on the road again.

By adding to an existing thread, even if years old, especially when it's a valid "addendum", makes it easier for everyone later.

2¢
E

[Linda]

Right Enrique. And I was the one spending the time looking as well.
Try searching for "brakes" for instance and prepare to be overwhelmed. Thus people give up and ask the same question over and over. Which is fine but not very efficient.
Anyway.... hope the info is helpful as that starter harness is quite important, it seems. And by the way a fellow owner tipped me to check there, so just passing on the info.

Linda

[K1200 GT]

OH..........

Richard

[spl310]

You mean this isn't a revival in the religious sense? Darn. I thought there was going to be a good hellfire and brimstone sermon coming...

[EScanlon]

Well, I'm hoping for some of that wine.... ¡Hic!

[dbrick]

Just a note, revival wise. If you have items wired directly to the battery, like fog lights, electric fans etc, or a GM alternator direct to the battery, the amp gauge will be wrong, almost all the time.