amp gAGE question

[jerry shook]

I put a new 70 amp alternator on my 31 s/w, with a new 30-30 amp gage. Problem is the needle stays in the middle all the time . I tried a new gage still the same, tried a 20-20 gage still the same,tested the alt it is charging. Any idea, help needed. Happy new year

 

[msmaron]

What are you trying to look for. Have you driven it yet and flipped on the lights to see if it moves??? Also WHY a 30-30 rather than the standard Amp Gage or an original that you know works?

 

[steve s]

two possibilities occur to me: 1. nothing is wrong. You're just not used to a well-regulated generator that instantly adjusts its output to match load. The ammeter measures net current flow in and out of battery, not the alternator output. If the battery is charged and the alternator is meeting the load right then, the ammeter will read very close to zero, especially so on a 30 amp gauge. 2. ammeter(s) is broken or not hooked up right. Does the meter deflect negative when you hit horn or lights with motor not running? After running battery down a bit, does meter deflect positive when motor is started?

Steve

 

[jerry shook]

I have driven the car with lights on no movement. The 30-30 works better with a 60 or 70 amp alt. Tried the old gage no movenent. Needle does not move when you blow the horn, turn the lights on . Left the lights on 15 min while eng not running , no needle movement. I have the same set up on another car that works great.

 

[Jim Parker Toronto]

Every wonder why late model cars do not run an amp gauge, but a volt gauge instead?

 

[darrylkmc]

With your car not running and the lights on do you show a discharge?
Turn the key to the On position, hit your brakes, each of these will show a discharge when the engine is not running.
If not you need to recheck your wiring through your Ammeter.

Darryl in Fairbanks

 

[msmaron]

or check to see if it actually works and I run a HIGH Voltage alternator from Nu Rex and an original amp and i feel personally it is much better and accurate!

 

[steve s]

I have driven the car with lights on no movement. The 30-30 works better with a 60 or 70 amp alt. Tried the old gage no movenent. Needle does not move when you blow the horn, turn the lights on . Left the lights on 15 min while eng not running , no needle movement. I have the same set up on another car that works great.

Jerry,
Either you've got two identically bad ammeters, which is pretty unlikely, or the wiring is wrong. I'm guessing you have inadvertantly not wired the ammeter into the circuit in series like it's supposed to be. You think you've got the same setup as your other car, but I'd bet you don't. It's not just a matter of a loose connection, or the car/lights/horn wouldn't run.

Is the hot wire from the starter switch going to the junction box post that has your ignition and generator wires, rather than to the post that only connects to the ammeter? That would give your symptoms.

Steve

 

[mrtexas]

I put a new 70 amp alternator on my 31 s/w, with a new 30-30 amp gage. Problem is the needle stays in the middle all the time . I tried a new gage still the same, tried a 20-20 gage still the same,tested the alt it is charging. Any idea, help needed. Happy new year

What problem? Is the battery going dead? If not, no problem.

 

[jerry shook]

With the car not running and lights on the amp shows nothing. I tried the old amp a 20-20 it does nothing, worked fine with the 30 amp altenator. The car had electronic ing when i boughe it with the 30 amp alt, the lights would not be bright enough when you had to stop , the horn would not blow unless the engin speed was increased. With the 70 amp alt lights work great and horn blows loud at idle. The only wireing i have done is i had to run a wire from the battery to the ing switch. For the electronic ing . I have tried all i know to do.

 

[msmaron]

Starting to sound like more than the amp problem here, have you check ALL the connections under the instrument panel and from there on out?, and have you checked your ground connections., Start at one point and trace the problem with a light.. DO NOT "Dive Bomb" you will find it, sounds like something somewhere is loose.

 

[steve s]

... The only wireing i have done is i had to run a wire from the battery to the ing switch. For the electronic ing . I have tried all i know to do.

Jerry,
Now I'm more convinced than ever that your problem is the wiring layout. If you really ran a wire directly from the battery to the ignition switch, you have bypassed the ammeter, which explains why it is not deflecting. If you follow the wiring, I think you will see that your new wire is not only feeding the ignition but also connects through the coil back to the post on the junction box that also connects to the alternator and thereby the lights and horn, all of which now avoid the ammeter. But, without seeing what other changes the guy who installed the electronic ignition unit may have made, it's impossible to tell you specifically how to fix.

Do you have a friend in local club who can trace electrical circuitry? It's fairly simple linear thinking but you need to know the principle and pay attention to detail. The principle is that there must be a conductive path for the electrons to get from one battery terminal to the other, and they must be forced to go through the "load" you want them to operate along the way; if there are two paths they can take, they will take the easier one, like, say, around an ammeter.

IF all your other wiring is really as originally laid out, removing your new wire and forcing the ignition switch to get its juice through the ammeter via the junction box should fix your problem.

Why did you have to install the new wire? Maybe the ammeter in the car that time, or one of the connections thereto, was bad.

In case you don't have one, here is a picture of the original wiring diagram. This was changed early-on to have that short black wire going from the coil to the top junction box lug actually go to the other junction lug; that way, the ignition circuit current was forced to go through and register on the ammeter. If you study this, I think you can see how your wire from the battery (actually, from the starter switch, I presume) to the ignition has bypassed the ammeter, causing it to not register.

Steve

 

[Bob C]

Where are the horn and lights getting there power from?

Bob

 

[Mike V. Florida]

With the engine not running (so it makes no difference what kind, if any, voltage generation you have installed) and the lights on you have to have a discharge showing in the meter if, 1) the meter is good, 2) it is wired correctly.

Wiring Diagram

 

[msmaron]

Where are the horn and lights getting there power from?

Bob

??? All the power comes from the positive ground battery,???.. Follow the diagram and you can trace all the lines to a base and to the areas it feeds.

 

[Bob C]

Mark,
What I'm trying to find out is where he has the wires that feed the lights and horn hooked. If for some reason they are hooked to say the starter switch then it's not
going to register on the ammeter.

Bob

 

[jerry shook]

Thanks to ever one, with out you i would be lost. When i think back the 70 amp alt , the 30-30-amp gage and the wire from the switch to the starter, i added about the same time. The reason i added the wire was sometimes the car would not crank, and when running if you turn the lights on the engin would stop running. I went on this form with the problem , some one suggested adding the wire, when i did the problem was fixed. I have another a i put the electronic ing and the instruction said to run a wire from the switch to the starter, no problems with this car. The car with the amp not working had the electronic ing on it when i bought it is the one were you have a chip in the dist and has a black box on the inside fire wall. I dont know the name of the ing, if someone does and has instruction to installing it i would like to have one . Happy new year.

 

[jerry shook]

Bob. To answer your question the lights and horn are hooked up like the other two a,s i have like the original.

 

[V4F]

ive run an alt for like 8 yrs . never a problem . as they have said , maybe the wiring is not correct ........ steve

 

[steve s]

Thanks to ever one, with out you i would be lost. When i think back the 70 amp alt , the 30-30-amp gage and the wire from the switch to the starter, i added about the same time. The reason i added the wire was sometimes the car would not crank, and when running if you turn the lights on the engin would stop running. I went on this form with the problem , some one suggested adding the wire, when i did the problem was fixed. I have another a i put the electronic ing and the instruction said to run a wire from the switch to the starter, no problems with this car. The car with the amp not working had the electronic ing on it when i bought it is the one were you have a chip in the dist and has a black box on the inside fire wall. I dont know the name of the ing, if someone does and has instruction to installing it i would like to have one . Happy new year.

Jerry,

This may be the diagram for your ignition unit.

It sounds to me like you have multiple problems. The intermittant failure to crank means you have a poor connection(s) between the battery and the starter. Most often this is on the grounding side. Even if the grounding strap connection is clean and the terminals are tight, the electrical path through the motor mounts (FLoat a motors) and sheet metal connections (especially if freshly painted) may be dicey. Go to the auto parts store and buy a grounding strap that you can run from the battery ground post to one of the bolts on the transmission. This will give electrons a good direct path to get back from the starter to the battery.

There is a chance that the ground might be related to your other problems--electronic ignition systems are notoriously insistent on having good grounds. Even if the unit is well grounded to the firewall per instructions, the firewall may not be well grounded back to the battery.

I still think that your ammeter problem is the fact that you have wired around it, as I explained previously.

Steve