Charging question

[Bagoftrix]

My gauge is reading all over the place. When the engine is cold the charging system reads fine. When it's warmed up the gauge settles in the middle. Turn anything on it drops more. I had it checked out by a corvette speciality shop and everything came up good. It just seems strange for the charging system to act this way if everything is "working". Any ideas?

 

[dougelam]

The charging system and the Guages are 2 different things when diagnosing.

One needs to monitor voltage at the battery output from the alternator and compare it to what you are seeing on the Guage when it is acting up.

Then go from there

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[LLC5]

My gauge is reading all over the place. When the engine is cold the charging system reads fine. When it's warmed up the gauge settles in the middle. Turn anything on it drops more. I had it checked out by a corvette speciality shop and everything came up good. It just seems strange for the charging system to act this way if everything is "working". Any ideas?

What are the voltage numbers you are talking about?

Give us some voltage numbers at the battery and what the gauge is reading at the same time with your above issues.

What is battery static voltage (with the vehicle off)?

 

[Scottsredvette]

Not to say that this is your problem because there are too many variables, but,,, My 89 did something similar and it turned out to be flaky diodes in the alternator. A good alternator repair shop figured it out for me. Don't remember what the cost was but it was cheaper than a new alternator.

 

[Bagoftrix]

I don't know what the static reading was, but the system was charging at 13.6. I'll definitely be testing it again and watching the gauge. Thanks for that advice. The car doesn't struggle when I start it. I've been noticing lately that the charging system only struggles (according to the gauge) when I have the heater going, which just happened to stop blowing hot air...another problem for another day.

 

[dougelam]

Like LLC5 said what is the battery voltage before you turn anything in?

Also when checking for charging irregularities one gets better results checking the output voltage right at the back in the alternator!

When it is running with all accessories turned on check for AC voltage at the back of your alternator, that will tell you if there is a bad diode

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[Bagoftrix]

Great!!! I'll do that. I was wondering how ro check the diodes. I really appreciate the help.

 

[Bagoftrix]

Ok...all fixed, but not by my diagnostic skills. Alternator finally decided to give up the good fight and seize up. Put in a new one today(ACDelco) and no more funky needle on the instrument panel. Thanks everyone for all your help!

 

[08 ZHZ DUO]

My gauge is reading all over the place. When the engine is cold the charging system reads fine. When it's warmed up the gauge settles in the middle. Turn anything on it drops more. I had it checked out by a corvette speciality shop and everything came up good. It just seems strange for the charging system to act this way if everything is "working". Any ideas?

Check your battery connections, you may have a loose cable.


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