Regulator. Wouldn't under drive pulleys make it spin FASTER, not slower?
electronics go dim when idling
Thread Starter
Instructor
Joined: Sep 2007
Posts: 145
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From: Morristown TN
electronics go dim when idling
My wife and went out tonight in the 88. While idling my blinkers would quit working and I could see the panel lights go dim. When moving or putting the car in park, everything would work again. However, when in park the blinkers were slower than when driving down the road. My first 2 thoughts were battery or alternator, but I am not for sure.
When idling while in gear, the voltage would go down to 10, then jump back up to about 13.5 when driving down the road.
I have done some searches here but apparently have not put the correct items to search for. I cannot find anything directly related to this problem. I'm still new to this and have only had the car for a week.
BTW, thanks to everyone for all the great posts. I have found many other things I am interested in.
Thank you for your responses.
When idling while in gear, the voltage would go down to 10, then jump back up to about 13.5 when driving down the road.
I have done some searches here but apparently have not put the correct items to search for. I cannot find anything directly related to this problem. I'm still new to this and have only had the car for a week.
BTW, thanks to everyone for all the great posts. I have found many other things I am interested in.
Thank you for your responses.
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Even at idle (in gear, brake on) you should see 14.3 volts, alternator cold, and this voltage will drop to 13.3 volts when the alternator gets to its normal operating temperature (normal operation). If the alternator is not charging the battery (and at 10 volts it is not charging your battery), then you should see the red battery symbol on the dash lit up. Normal idle rpm is 700-800 (unusually low rpm will cause low alternator voltage). I would suspect a defective alternator. Take the alternator to a parts place, most will test them free (tell them it has no output at idle rpm). Check the nut on the alternator output bolt for tightness (don't touch your wrench to ground or you will blow out the fusible link on the output wire).
Team Owner
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Might have underdrive pulleys. PM the pulley diameters.
Also check the battery cable connections and clean as required.
Also check the battery cable connections and clean as required.
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Instructor
Joined: Jul 2007
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From: Toronto Ontario
Check for rust/corrosion and clean ( with wire brush) battery terminals, alternator terminal, ground terminal at engine block (beside oil filter, its a big nut). Check continuity with DVM on wires (battery disconected) leading from positive battery term to alternator red wire term and negative term to alternator housing. Run the engine and see if voltage comes back up to 14.5volts at idle. Post results and we will go from there.
Safety Car
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Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
I'd love to run my March underdrive pulleys all the time. But the street drive ability is less than desirable. Especially at night.
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Safety Car
Joined: Jul 2004
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Huh? IF the crank pulley is smaller than stock, the rest of the accessories will turn slower not faster. Thats why your alt is dropping offline at idle.
I'd love to run my March underdrive pulleys all the time. But the street drive ability is less than desirable. Especially at night.
I'd love to run my March underdrive pulleys all the time. But the street drive ability is less than desirable. Especially at night.
Last edited by Da Mail Man; Sep 23, 2007 at 02:48 PM.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 145
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From: Morristown TN
I put on a new alternator. They checked it at AutoZone and said it was not putting out at all. (Like an old girlfriend) Anyway, it seems to help in idling while in park, but I still see a drag when in gear at a stop. The gauge goes down to 11.5 at times, which is still better than the 10.? it was going down to. When I turn off the air, then it kicks back up to 12.5, sometimes going to 13. Seems the air is putting a real drag on the system.
Safety Car
Joined: Jul 2004
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I put on a new alternator. They checked it at AutoZone and said it was not putting out at all. (Like an old girlfriend) Anyway, it seems to help in idling while in park, but I still see a drag when in gear at a stop. The gauge goes down to 11.5 at times, which is still better than the 10.? it was going down to. When I turn off the air, then it kicks back up to 12.5, sometimes going to 13. Seems the air is putting a real drag on the system.
Instructor
Joined: Jul 2007
Posts: 174
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From: Toronto Ontario
I put on a new alternator. They checked it at AutoZone and said it was not putting out at all. (Like an old girlfriend) Anyway, it seems to help in idling while in park, but I still see a drag when in gear at a stop. The gauge goes down to 11.5 at times, which is still better than the 10.? it was going down to. When I turn off the air, then it kicks back up to 12.5, sometimes going to 13. Seems the air is putting a real drag on the system.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
It would not be unusual to see battery voltage with all the accessories on. The 105 amp alternator is only putting out 30 to 35 amps at idle. The HVAC blower can sap 25 of that, the main fan 10 and with the headlights and radio on, the alternator isn't going to keep up. GM will tell you it's normal. In fact they issued a Bulletin telling Dealers that they were not going to reimburse them for warranty claims if the only complaint was that the lights were dimming at idle. The only solution is a bigger alternator. In the interim, you can verify the gage readout by checking the voltage at the Battery with everything on and the car in gear. You can also check it on both sides of the ignition switch as corrosion between the contacts will make the gage read less. Finally, if you've rigged both fans to run for cooling, get it back to where only one fan is engaged. With both going, it's simply adding to the problem and once the voltage drops, they're going to slowdown and your coolant temps will climb.
Last edited by SunCr; Sep 24, 2007 at 04:35 PM.
Team Owner
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
A cyclic event that takes place usually in the spring is all the threads about batteries and alternators. (Leading into the winter is heater core hell.)
The Corvette that is not driven on a daily basis is going to tax the alt in an attempt to charge the battery when driven. Add to this the lame (105 amp) standard alt that the General equipped us with.
So the alt is working harder than it should and the battery is being cooked during each weekend outing. Its no wonder that the average C4 Vette battery lasts only one year. And its replacement is usually followed closely with an alt exchange as well.
The remedy is to use a battery tender. An inexpensive device that is plugged into the wall and then to the battery during the "rest" periods. I started using one of these two years ago and have had no further batt/alt problems. "Rose" gets about 6 outings a month now and the alt stays within normal temps after running.
The Corvette that is not driven on a daily basis is going to tax the alt in an attempt to charge the battery when driven. Add to this the lame (105 amp) standard alt that the General equipped us with.
So the alt is working harder than it should and the battery is being cooked during each weekend outing. Its no wonder that the average C4 Vette battery lasts only one year. And its replacement is usually followed closely with an alt exchange as well.
The remedy is to use a battery tender. An inexpensive device that is plugged into the wall and then to the battery during the "rest" periods. I started using one of these two years ago and have had no further batt/alt problems. "Rose" gets about 6 outings a month now and the alt stays within normal temps after running.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 145
Likes: 0
From: Morristown TN
The remedy is to use a battery tender. An inexpensive device that is plugged into the wall and then to the battery during the "rest" periods. I started using one of these two years ago and have had no further batt/alt problems. "Rose" gets about 6 outings a month now and the alt stays within normal temps after running.
Thanks to everyone for all the great feedback. This forum is the best. I did notice today the car started better since putting the alternator on. Sounds like the battery is now staying charged better than it was before.