What is Normal Ammeter Behavior?

[Reed64]

My charging system has been acting up on my 64 390. When the charging was working ok, I didn't pay much attention to the ammeter. Now I'm always watching it and I'm sure it is not normal.

With lights off and engine running, the needle will stay in the middle for about a minute, then it go about half way to "C" (sometimes all the way) for a few seconds, then snaps back to the middle for a minute or so. This repeats over and over. It is as if a switch allows current to flow to the battery for a while then stops all flow for a while.

With the lights on, it acts similarly, but instead of the needle being in the middle, the needle sits to the left towards discharge.

By the way, I actually have a 65 alternator installed. And I believe I have the electronic replacement regulator, not the original type.

What is normal ammeter behavior?

[4-5-6-birdman]

Originally Posted by Reed64

My charging system has been acting up on my 64 390. When the charging was working ok, I didn't pay much attention to the ammeter. Now I'm always watching it and I'm sure it is not normal.

With lights off and engine running, the needle will stay in the middle for about a minute, then it go about half way to "C" (sometimes all the way) for a few seconds, then snaps back to the middle for a minute or so. This repeats over and over. It is as if a switch allows current to flow to the battery for a while then stops all flow for a while.

With the lights on, it acts similarly, but instead of the needle being in the middle, the needle sits to the left towards discharge.

By the way, I actually have a 65 alternator installed. And I believe I have the electronic replacement regulator, not the original type.

What is normal ammeter behavior?

Reed, you need to confirm which style regulator you have. From your description it sounds like the point style. You also don't state what happens with an rpm range in the 1500 to 2300 which is cruise range. This is the range in which things should also be observed, try running the rpms up and then pulling on the lights. The condition on you state about the flow to the battery being stopped is exactly what happens if a fully charged battery is sensed. I would expect to see a more gradual movement of the needle however.

Do you have a factory service manual? The section on charging is pretty informative and useful. It sounds to me from your description you have a point style regulator, the book stresses erratic needle behavior for that style can be caused by pitted or oxidized points which can be sanded and cleaned. If you do have the transistorized style it might be bad. Are you having any problems with the system, dead battery, overcharged battery? If not the system is probably working ok. I would do the test with the lights at cruise rpms and observe the gauge. Good Luck!!

[Reed64]

Originally Posted by 4-5-6-birdman

Reed, you need to confirm which style regulator you have. From your description it sounds like the point style. You also don't state what happens with an rpm range in the 1500 to 2300 which is cruise range. This is the range in which things should also be observed, try running the rpms up and then pulling on the lights. The condition on you state about the flow to the battery being stopped is exactly what happens if a fully charged battery is sensed. I would expect to see a more gradual movement of the needle however.

Do you have a factory service manual? The section on charging is pretty informative and useful. It sounds to me from your description you have a point style regulator, the book stresses erratic needle behavior for that style can be caused by pitted or oxidized points which can be sanded and cleaned. If you do have the transistorized style it might be bad. Are you having any problems with the system, dead battery, overcharged battery? If not the system is probably working ok. I would do the test with the lights at cruise rpms and observe the gauge. Good Luck!!

Thanks for the reply. I think I have the electronic regulator, it is new but I will replace it just in case it is bad. The problem that just started happening is a super slow crank when starting or no crank at all. This problem started soon after I installed the Ignitor ignition with the Flame Thrower coil. With the new coil, the engine starts after only 1 or 2 cranks, but the cranks are hard to come by. Is it possible to have a full battery but a very slow crank? Could the new coil be the cause? I'm going to check the battery tomorrow.

[4-5-6-birdman]

Originally Posted by Reed64

Thanks for the reply. I think I have the electronic regulator, it is new but I will replace it just in case it is bad. The problem that just started happening is a super slow crank when starting or no crank at all. This problem started soon after I installed the Ignitor ignition with the Flame Thrower coil. With the new coil, the engine starts after only 1 or 2 cranks, but the cranks are hard to come by. Is it possible to have a full battery but a very slow crank? Could the new coil be the cause? I'm going to check the battery tomorrow.

No ignition is seperate from the starter circuit, are you using a ballast resistor on one side of the coil? They originally were used to reduce high current to the points during engine cranking. If you have electronic you should remove the ballast if you have one. The only way you'll have a slow crank with a full battery is if your starter is drawing too much current. Almost sounds like your battery might be on the way out, how old is it? The coil would not be the cause of slow cranking either. Are you certain all your lugs are clean and tight and you have a good ground connection to the block? Good Luck and keep us posted!

[boaterbob]

How about the timing being to far advanced and the battery not 100%.

[4-5-6-birdman]

Originally Posted by boaterbob

How about the timing being to far advanced and the battery not 100%.

Was the distributor removed to install the Pertronix? You stated that the condition just started after the ingnition change. As the Boat man states if you did pull the distributor you will need to retime. I reread your post and it still sounds like a bad or dirty lug/terminal or a bad cell/bad battery or a problem with the regulator. One good course of action,if you can get the old Bird down the road might be to roll into your local Chain Auto Parts store and ask for a free charging system check. No point in throwing good money away for an already OK regulator. Good Luck and keep us in the loop!

[Reed64]

Birdman, I did not remove the distributor when insalling the Pertronix.

My battery was fairly new so I charged it using a home charger and it's back to 100%.

Then I installed a new electronic replacement regulator from Birdnest. This regulator was definitly different than the one I had earlier that I bought from Thunderbird Headquarters. It was fatter and only partially chrome. Anyways, it definitly made a difference in terms of ammeter behavior.

Now the ammeter stays on the Charge side most of the time, which is good. It only goes towards Discharge when I'm at a stop with the headlights and breaklights on. But it is wiggling a lot now whereas before it was steady. It wiggles the biggest distance back and forth when I'm going about 25 mph with my foot off the gas. I'm not sure what is causing this. Loose connection maybe?

I'm still curious how other people's amp gauge behaves? Any wiggling?

[boaterbob]

No wiggles in Boater's guage.

[boaterbob]

You could get a cheap Voltmeter and hook it up to your Lighter or any switched hot wire. This would give you a much better indication of whats going on with the system, If anything.

[Harley Eaton]

Would not the voltmeter simply tell you the condition of the battery? If the charging system was not working at all, the voltmeter would indicate battery voltage. Right?

[boaterbob]

Yes i agree, But if you were only charging at maybe 12 volts it may show that better after running the car for a short time or if it jumps up to say 16 volts it shows up on the meter right away. With the numbers on the voltmeter it's just another way to get a handle on whats going on.