Battery/Alternator problem???

[slapshot]

Just before I got home today, the battery warning light came and the dash voltmeter was reading noticeably lower than normal. When I got home, I put a meter on the battery and got 12.24v with the car off, and 11.99v with it idling. As it idled, the volts slowly were dropping, until I turned the car off at 11.85. The battery read 12.24v after also.

I've only had the car about 6 months now, so I have no idea how old anything is. I know the battery was replaced on 7/14/03, and is under full warranty, I have a receipt from the previous owner for that.

The alternator looks like it's been replaced because it's slightly cleaner than everything else.

Is there an easy way to test the alternator????

It has ran fine since I bought it. Today was actually the first day I ran the A/C, so the power draw was probably pretty high.

If I had to guess, I'd say the alternator is shot since there is a draw and no recharge when it's running. I know they are a common problem. But I figured I'd tap into the expertise here first. And yes, I tried a search already.

Once the motor cools off, I'm going to check the connections on the battery and alternator just to make sure it isn't something easy.


update.....all of the connections look good. When running, RPM doesn't affect the battery voltage at all, it starts around 11.98 and slowly drops.

 

[Hrtbeat1]

Sound like the voltage regulator is failing. If you go to an Advance Auto or Autozone they should be able to test your alternator for you. They can do it in car.

 

[slapshot]

Sound like the voltage regulator is failing. If you go to an Advance Auto or Autozone they should be able to test your alternator for you. They can do it in car.

Is the voltage regulator built into the alternator???

I'm curious how long it will run if it won't recharge.....hopefully it will make it to the auto part store to get tested. I may just go buy one....it needs spark plugs, etc too....so I was going this week anyway.

 

[Hrtbeat1]

The regulator should be internal to the alternator. I think the blue ovals are the last to use an external regulator. As far as how long it will run???? Who knows but if your voltage is below 12 it probabally wont run very long. There is a table that the ECM uses that deals with injector pulse width vs battery voltage, but I'm not sure how low the battery voltage can go.

 

[slapshot]

Thx much......since I'm pretty sure that's the problem, I'll just buy one this week when I go for the tune up stuff. I'll swap it out next week on my days off.

Atleast the alternator is easy to go to on a Vette

 

[Hrtbeat1]

LOL :L I think its the only thing!

 

[slapshot]

LOL :L I think its the only thing!

Yup, that's the truth!!!!

 

[G Winter]

Be sure to charge the battery after you have the alternator replaced. It could take the alternator a long time to catch up with the air running etc.
I believe your problem is the alternator. could be a broken wire or dirty connection but the dirty connection should effect starting .

 

[jcs44]

Whatever you do, do it soon. Once the battery drops to 11 volts, the car will start but will die right away because the computer doesn't see enough juice. The electrical system on a C4 will drain the battery over a couple of weeks if the car isn't driven very much. It's a good idea to put a peak charger on it to keep the battery up as even a good alternator will not charge up a low battery (it only maintains it). Good luck.

JCS44
LT4 Vert

 

[Jeroenvgfn]

Isnt there a automotive repair shop in your area which can fix the voltage regulator.


I my town we can drop the alternator off and they clean,test and repair the alternator for you.

the fix will only be a few bucks max.

at least in The Netherlands it can be done like this, but it could be a typical dutch thing cause were are the cheap goates of Europe

 

[SPANISHVETTS]

Measure the voltage at the alternator with the engine running 1000RPMs or more. Anything less than 14.5 volts the Alternator is shot. The stock alternator on early C4s is crap and prone to failure. Replace it with a heavy duty – hi output model and your worries are over. As suggested above charge the battery up with a battery charger - charging it with the alternator will overheat and destroy a stock CS130 unit.

 

[slapshot]

Measure the voltage at the alternator with the engine running 1000RPMs or more. Anything less than 14.5 volts the Alternator is shot. The stock alternator on early C4s is crap and prone to failure. Replace it with a heavy duty – hi output model and your worries are over. As suggested above charge the battery up with a battery charger - charging it with the alternator will overheat and destroy a stock CS130 unit.

For testing the alternator...is it as easy as going from the single wire connector on the alternator to a ground??? The only other connector is the 3 wire plug.

 

[slapshot]

Isnt there a automotive repair shop in your area which can fix the voltage regulator.


I my town we can drop the alternator off and they clean,test and repair the alternator for you.

the fix will only be a few bucks max.

at least in The Netherlands it can be done like this, but it could be a typical dutch thing cause were are the cheap goates of Europe

Yes, I was gonna make some calls this week. I have a take home cruiser from work that I can drive off duty, so if the Vette is down for a few days it won't really matter much.

 

[WhalePirot]

we are the cheap goates of Europe

.Thrifty is nifty, and not exclusive to the Dutch. Nice to see some humor below sea level. :L

Ensure, if you buy a replacement that it is not just rebuilt. Either spring for new or get remanufactured. That way you get ALL new innards, not just what they found worn. Personally, I have a favorite shop that redid mine, and did it very well. He also upped the output as much as possible, using American made parts, which are visibly superior, but must be specially ordered.

I am not a fan of the chain stores for testing, especially electrical. A decent shop can test your car, even do a VAT test if needed, and quickly find the correct fix. It does, however, sound like an alternator issue, and I believe you have already heard some great advice.

 

[SPANISHVETTS]

For testing the alternator...is it as easy as going from the single wire connector on the alternator to a ground??? The only other connector is the 3 wire plug.

Yelp, just mesure from the red wire on the back of the alternator to ground.

Several companies sell heavy duty CS 130 alternators. Follow WhalePirot´s advice and get a completely remanufactured unit. Most of the Cheapie shops just replace the diode pack or voltage regulator.

Back in the days of the Delco 10-SI this was good enough because the 10-SI was over built but the CS 130 is borderline when it is new so replacing the first part that dies will only lead to the next failure. (This comes from experience.)

The better remanufactured units have a different back case with cooling fins and a larger bearing. They still cost less than a new one Delco.

 

[slapshot]

gotchya

thanks all for your help.

 

[jsinga]

My advice after 10 years with my 87. ONLY get an alternator with a lifetime warranty!!! I have put 4 on. One before I got the car was a genuine AC Delco reman. It lasted just over 2 years the warranty; half that time it sat in the driveway while I was in Korea. It made 3 months in the Oklahoma summer and died from the heat. Got a PepBoy's lifetime rebuilt. It lasted about 3 yrs. After it died the last 2 have been brand new alternators. I think the other posts are on the mark about the battery. I think a weak battery killed at least one alternator. I talked to an auto electric shop and they told me heat kills most of the alternators in FWD, Firebirds and Vetts since they don't have engine driven fans. He said they could build up an alternator with 160amp truck parts but it might not last any longer. One thing I think will help is a lower temp boost fan switch (if you have the small fan out front) it runs off a temp switch behind the alternator. I got one that comes on @ 200 degrees instead of 230 like the factory switch.
Just my .02!

js

 

[slapshot]

Thanks jsinga....I'll be getting a new one Monday...

how much do they run??

 

[slapshot]

I checked the alternator this morning.....it's a Delco Reman, so I know it isn't stock. At idle, it's only putting out 11.55v. I'd think it would be up around 13-14v.......and that was directly rom the red lead to ground.

 

[jsinga]

Last I heard @ $140 from PepBoys. They are new not GM. I paid $80 years ago and have gotten 3 now!


JS