Fan/gen light, 66 Monza auto

[rudyck]

Hi all,
Just had the rear control arm bushings and strut rod bushings replaced along with new shocks. Before the work was done, the fan/gen light would come on when you turned on the ignition, and as soon as the engine started, it would go off. Since the work, it still comes on when you turn on the ignition, but when the engine starts, the light glows dimly at idle, (fast & slow). When you rev the engine to about 800/900rpm the lights go out.
Is there something under the engine that has been disturbed?? Where are the fan & gen sensors located? Seems odd to me that I'm now having this problem right after I got the car back from the garage. Any ideas????? It does not overheat and the battery stays charged. Any help would certainly be appreciated. Thanks,

Rudyck
66 Monza Vert
Arkansas

[Jerry Whitt]

Your description fits the symptoms of a low idle speed.

[91blaze]

The light is controlled by the alternator itself, do you have the stock external regulator alternator, or a modern regulator resistor. I have an internal regulator alternator and my light stays on dimly when idling, just like yours. It's not been a problem yet and I've been driving it daily for several months now. If everything is still stock I'm not sure what the problem is, hopefully someone can chime in.

BTW, do you know your idle speed? It should be around 600-700, if it's much lower that could be the problem.

[rudyck]

Thanks for the info. I put a tack on the engine this morning and I'm running about 1500rpm at fast idle, in neutral, and 600rpm at normal operating temp, in neutral. My owners manual states that all power glides (regardless of engine configuration), should be set at 450-500rpm in drive. Well, mine is running at 500rpm at idle, in drive.
Nothing on the engine has been changed, so I just don't understand what is now causing the problem to show up after getting it back from the shop. As I mentioned, it does not overheat and the battery stays charged, so maybe I should just live with it. Just very strange. If you have any other ideas, I'll be pleased to check them out. Thanks again.

Rudyck
66 Monza Vert
Arkansas

[rudyck]

I have only had this car for about 2 years, but the voltage regulator and alternator look original to the car. But not knowing the history of the car, these items could have been replaced thru the years. I just never had encountered this problem before it went into the shop. The shop did nothing under the rear deck lid, except maybe disconnect the battery. I guess I just don't want to accept that this may just be coincidence, and after 48 years, the alternator or voltage regulator has bit the dust. Thanks for your insight.

Rudyck
66 Monza Vert
Arkansas

[bbodie52]

The generator warning light only glows when there is a difference in voltage on two sides of the circuit. A battery voltage with no generator output makes the light glow. When the engine starts and the generator begins to produce voltage, an output equal to the battery voltage will extinguish the light. If the voltage sensed is slightly lower due to a voltage drop somewhere in the circuit, the light may glow dimly. It might be that a bad ground or a dirty electrical contact somewhere in the circuit is causing a voltage difference, and causing the light to glow dimly. I did read a few comments on various websites where some theories mentioned a possibly failing diode in the alternator, but those theories were not confirmed.

[rudyck]

Thanks Brad, your info was very helpful. Is there a way to check whether the trouble is the alternator or voltage regulator??? And, if I need to replace the alternation, can I convert to a 1 wire alternator?? About an hour ago I went out to go on an errand, and the battery was too low to crank. So, now I have the charger on it and it starts right up. Meter on charger shows about 65/70% charged. Your thoughts would be appreciated. Thanks again Brad..

Rudyck
66 Monza Vert

[91blaze]

What's your battery voltage when running? This information could help identify a problem. If you do decide to upgrade to a new alternator, look around here for directions. Many people including myself have done it and will give advise where needed.

[bbodie52]

Is there a way to check whether the trouble is the alternator or voltage regulator??? And, if I need to replace the alternator, can I convert to a 1 wire alternator?? About an hour ago I went out to go on an errand, and the battery was too low to crank.

IN-STORE SERVICES
Free Testing *

Some places charge you for testing your car, but at AutoZone, it's free.

Don't buy a part you don't need. AutoZone will test your car's parts for free. We can test your car's battery, alternator*, starter* and voltage regulator* while they're still on your car. We can also give your car a complete starting and charging systems test. You can also take your alternator, starter or battery into our store and we'll test it. In most stores, we can also test voltage regulators, control modules, coils, throttle position sensors (TPSs) and other engine management components.
* Service not available in CA

I would suggest calling your local AutoZone, or similar auto parts store, and see if they offer this service. They seem to indicate that they can test your battery, regulator and alternator either in the car or out of the car (in the store). You can ask them about this and which is preferred. Such diagnostic testing will hopefully help you to zero-in on the fault(s) in your car. If your battery is fully charged they will have the test equipment to perform a battery service and load test to determine the condition of your battery, and its capability of producing full voltage, good cranking amps, and of holding a charge.

I understand that 1-wire alternator configurations can be problematic. They have several drawbacks, and few advantages...

• Typically, after starting the engine, the engine must be revved above 1200-2000 RPM to turn-on the 1-wire alternator.
• The ignition warning light indicator function is omitted with a 1-wire alternator, so your idiot light will not be operational with this setup. (This is a critical element in a Corvair, because it not only monitors the status of your charging system, but it is used to announce a flipped or broken fan belt before your engine overheats!)

Alternators with electronic internal voltage regulators can be fitted to a Corvair. A 3-wire alternator is preferred. Recommend you follow this link for an excellent explanation...

Alternator Conversion
Selecting a Delco SI-Series Alternator
1-Wire or 3-Wire?

[url]http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html[/url]

[rudyck]

OK, I just went out to the garage and took some battery voltages.
With engine off------------------12.35
@1200rpm------------------------12.12
@600rpm--------------------------12.12
@2000rpm------------------------12.15
Then with engine off------------12.25
Got the same reading when testing the output terminal on the alternator.

Unless the regulator controls this voltage, I'd say the alternator is defective. The dash light goes out at about 1800rpm, but the voltage stays the same.

After reading that article on alternator conversions by Bob Skelly, I think I will stick to the original 3 wire setup. Should I start shopping for a rebuilt alternator, seems like they are plentiful.

Thanks again Brad & Blaze, your assistance has really been appreciated. What is your take on the voltage readings??

Rudyck
66 Monza Vert.

[rudyck]

Hi guys,

Took the alternator off and had it checked at O'reilly and it checked good. So rather that screwing around, I ordered a new voltage regulator and condenser. When I took the old VR off I drilled out the rivets, thinking I would file the points, but it is not original equipment, it's solid state. No repair possible.

Thanks for all the expert advice, this is a great forum for us Corvair Junkies.

Rudyck
66d Monza Vert
Arkansas

[rudyck]

Well, the VR and condenser did the trick. All is back to normal and the voltage across the battery at fast idle is 14.2. Thanks again for all your suggestions and valuable help.

Rudyck
66 Monza Vert.