98 corvette volt issue
Thread Starter
Intermediate
Joined: Sep 2011
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98 corvette volt issue
when i start the vett the volt say 11.5 after 30 sec will go to 13.6 volt after warming up to 220 temp will start dropping to 12.3 and if i run the lights and a/c drops to 11.8 and now on my sec alternator in 2 month and just replace the battery with 800cca ps: when i frist start the motor i get a message telling me i have charging system failed prom. please help
Heel & Toe
Joined: Nov 2010
Posts: 21
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charging system
with a multi meter check your battery voltage at the battery terminals. engine not running. start engine check voltage at battery terminals and then cables. voltage should be the same on battery and terminals, the voltage should be higher than when it wasnt running. appox 13.9v -14.2v. if higher on cables, bad connection to terminals. put a load on ( bright headlites ) have idle at appox 1500rpm and the voltage should be the same at either cable or post. 13.9-14.2. the portions of voltage doesnt matter as long as it is either 13-14v. you can also get an amp probe that will fit over the alt. cable to see what the car is drawing for amps. if you do not have these tools, they are very inexpensive but can be easily used and solve many problems without taking apart items by trial and error. good luck
Heel & Toe
Joined: Nov 2010
Posts: 21
Likes: 0
charging system
i should have said also to fully charge the battery so that you know what you are starting with. should be at least 13.5v. also check to see what you might have for accesories that are drawing off the battery when the car is off. alot of security systems, audio, tachs, gauges lighting ect could be drawing off the battery. you can check this by charging the battery to a full charge read voltage, let sit for 24 hrs and check again. there are other ways but this is pretty easy.
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
Likes: 0
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
Likes: 0
with a multi meter check your battery voltage at the battery terminals. engine not running. start engine check voltage at battery terminals and then cables. voltage should be the same on battery and terminals, the voltage should be higher than when it wasnt running. appox 13.9v -14.2v. if higher on cables, bad connection to terminals. put a load on ( bright headlites ) have idle at appox 1500rpm and the voltage should be the same at either cable or post. 13.9-14.2. the portions of voltage doesnt matter as long as it is either 13-14v. you can also get an amp probe that will fit over the alt. cable to see what the car is drawing for amps. if you do not have these tools, they are very inexpensive but can be easily used and solve many problems without taking apart items by trial and error. good luck
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
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With the engine running check the alternator output at the alternator terminals. Then check it at the battery. If there is a big drop in voltage at the battery compared to at the alternator then the cable between the alternator and battery is suspect. Have heard of many cases where the cable is bad and an alternate one was run to avoid the bad one.
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Le Mans Master
Joined: Apr 2002
Posts: 6,927
Likes: 3
From: Glendale NY
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18- '19
Alternator
when i start the vett the volt say 11.5 after 30 sec will go to 13.6 volt after warming up to 220 temp will start dropping to 12.3 and if i run the lights and a/c drops to 11.8 and now on my sec alternator in 2 month and just replace the battery with 800cca ps: when i frist start the motor i get a message telling me i have charging system failed prom. please help
14V - 110A alternator. Could this be your problem?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
If you are using the DIC to measure your battery, don't. Use a DVM at the battery itself. Next, there's a ground connection between the battery and fuse box down low and this is the ground path for the where the DIC measures the battery. Now the next place to go is the solenoid. From the alternator, going to the solenoid, there's a fuseible link which connects at the solenoid therefore make sure the solenoid connections are clean and tight, not forgetting they are electrically hot.
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Did some more testing with the car runing alt only putting out 12.5 and and the battery charging at 12.5 both the same turn on headlights a a/c amp drop 11.8 and holding battery & alt are good and the right ones per dealer I think its the 3 wires from the alt one of them are bad going to start there
Le Mans Master
Joined: Apr 2002
Posts: 6,927
Likes: 3
From: Glendale NY
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18- '19
Did some more testing with the car runing alt only putting out 12.5 and and the battery charging at 12.5 both the same turn on headlights a a/c amp drop 11.8 and holding battery & alt are good and the right ones per dealer I think its the 3 wires from the alt one of them are bad going to start there
Who is this dealer you mention? Chevrolet dealer, used car dealer, street corner dealer. I know a lot of dealers....I'm just trying to help, look at the alternator and make sure it's a Valero, made in France,
part #10246634 14V - 110A.
If this turns out to be your problem, you owe me a beer.
Heel & Toe
Joined: Nov 2010
Posts: 21
Likes: 0
volt issue
i dont see how the dealer could say the alt is good. it might be the right one but the charging voltage should be higher. check right at the alt. that will keep the cable out of the problem. did you also get the probe to see the amp draw?
Thread Starter
Intermediate
Joined: Sep 2011
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Look at the alternator and make sure you got the right one.
Who is this dealer you mention? Chevrolet dealer, used car dealer, street corner dealer. I know a lot of dealers....I'm just trying to help, look at the alternator and make sure it's a Valero, made in France,
part #10246634 14V - 110A.
If this turns out to be your problem, you owe me a beer.
Who is this dealer you mention? Chevrolet dealer, used car dealer, street corner dealer. I know a lot of dealers....I'm just trying to help, look at the alternator and make sure it's a Valero, made in France,
part #10246634 14V - 110A.
If this turns out to be your problem, you owe me a beer.
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
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Yes says 12.5 to 12.8 now i look for one that ism 110 a 14v
Le Mans Master
Joined: Apr 2002
Posts: 6,927
Likes: 3
From: Glendale NY
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18- '19
My alternator in my 1998 works fine. As a matter of fact it has 230,000 miles on it.
1997 and 1998 must use the alternator I have mentioned above.