Alternator Gauge

[lgarbz]

I have a 74 duster with a slant six.
When i'm driving, the needle in the alternator gauge stays about in the middle, but when im braking and at idle speed, the needle dips to the left quite a bit. I've installed a new voltage regulator and that did not fix it. is this caused by the idle speed? and if so, which screw do I need to tighten or loosen on my carburetor?

Thanks

 

[Judge Mills]

If I remember correctly, that is a amp meter, and not a voltage gauge, meaning every time there is "discharge", the gauge dips, like when the idle is low. I would eliminate the amp meter and convert to a volt meter that shows you the discharge of the alternator. I know someone will come along and explain this better, but in the mean time, don't worry.

 

[cudajim]

It's called an ammeter (amp meter) which measures current (in amps) going into or out of the battery. It is normal to see a discharge while idling, especially if you have everything on. When you rev the engine the alternator puts out more current and you see a charge condition on the ammeter. You can add a voltmeter (which measures volts) to get a warm fuzzy feeling that all is well but it won't tell you much.

Your idle may be a bit low and you can bump it up just a bit by turning the idle adjustment and/or the mixture screw on the carb.

 

[lgarbz]

Thanks for the replies. In regards to the electrical system, is there anything I can do to bump it up? when the ammeter drops low at idle, the headlights/dash light dim, and wiper motor slows down. That's the only reason I have an issue with the gauge dipping. is there an easy fix for that?

 

[Dubob]

You may wanna check the connections at the fire wall where all the wires connect going into the passenger compartment. There will be a couple of larger guage wires that are the main supply for the cars electrical system (fuse block). They may be corroded or even have melted the plastic connector. Dodge had some issues with the ammeters in their pick ups and there were issues with things burning. I plan on doing away with the ammeter on my demon and using a volt guage. Have read where the process actually improves the lights dimming at idle etc. There are several articles on the net that are how toos to bypass the amp guage. I wanna do it for safety of not burning the car up.

 

[cudamark]

I'd keep the ammeter.....I like them. They'll tell you more about the charging system than a simple volt meter but adding a volt meter is not a bad idea. I wouldn't set your idle up any higher than what the specs are. If you do, it's hard on the u-joints and gears in the rear end. One method I've used to boost the output at idle is to get a smaller diameter alternator pulley.

 

[lgarbz]

Thanks for your responses. I've had issues with this carburetor in the past, but I've finally got the idles back to normal. Dash lights still dim a little, but there's been a noticeable change. Another thing that completely slipped my mind was that the alternator belt might be a little loose from the last time I was messing with it. That might have something to do with it also. I'll post again when problem's solved.

Thanks guys.