2005 Honda Accord over charging alternator

This one has me stumped???
2005 Honda Accord with a 2.4, automatic.

I am working on a car that the owner reported that,

  1. the battery light was on when she left work and
  2. the car ran fine on her way home (12 miles) then started having issues…like it was missing and
    coughing and sputtering when she pulled into her driveway.

The car started fine for me but upon checking the voltage at the battery I had 18.9 volts.

I replaced the alternator, thinking that the internal regulator was the problem. At the same time I replaced the battery as it was already 5 years old. I also replaced the serpentine belt at this time.

This new alternator was putting out 19.2 volts upon start up.
I returned this alternator to the parts house and they gave me a new one.
This second new alternator was putting out 19.4 volts

This alternator has a internal regulator so I am lost as to where to go next with this.

Am I missing something???

Any help or ideas would be appreciated.

Yosemite

The ECM/PCM regulates the voltage from the alternator to the battery.

Tester

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Honda has a related TSB, 12-002, dated 9.12.2005

Like Tester says above, the engine computer is involved in the charging system. Make sure the connectors from the alternator going to the engine computer are in good shape. Could be a grounding problem too. Make sure the alternator is mounted in the standard way, no plastic shims have been added preventing the ground from the alternator case to the chassis ground. The ECM/PCM connector terminal, both pin 18 & pin 10 should be connected to body ground from what I can see too. Caution required when probing ECM connectors to avoid damaging the ECM.

Is the 19 volts at the alternator terminal or at the battery terminal?

@ok4450

Both terminals, the positive at the battery, and the alternator post, both read 19 volts.

Yosemite

@George_San_Jose1…are you sure of that number of that TSB.

Yosemite

Yes, that’s the correct number as far as I can see. Just reference info fyi, not saying it applies to your problem. It’s a TSB update to their recommended test procedure in the service manual on how to test the alternator. It’s the only TSB I can see for the alternator/charging system.

I found the problem with the high voltage. And I would like to thank @Tester , @George_San_Jose1, and @ok4450 for your input. @

It turned out that my multimeter was bad.
I tested it on another car and on my Dodge Dakota. Both of those vehicles showed that they were charging
18.4v to 19.2 volts.

I happened to remember that I had a small meter that plugs into the cig lighter in my truck. I used that and the Accord was charging at 13.7 volts at idle.
The other two vehicles were tested with this meter and both within 13.8 and 14.2 volts at idle.

i then took the Accord to my local parts store for them to check the charging system with their equipment and the charging was at 13.9… pretty close to what the little cheapy that i plug into the cig lighter.

Now i’m wondering about the two parts stores that tested the old alternator …both NAPA and O’Rileys tested the original alternator and both said that it was not charging at all. Zero Volts???
My parts house couldn’t test it because they couldn’t find the proper plug for that design. Someone misplaced it!!!

Maybe the original alternator was good and the only problem was the old battery.

Now I need to buy a new Multimeter and throw this one in the garbage.

Yosemite

Congrats on getting it sorted out. Some people may have beaten their heads on the wall for weeks figuring this out.

My daughter gave me a more expensive VOM as a birthday gift a few years ago. I didn’t need it but nice gesture anyway. About 6 months later I opened the package and noticed the LCD display was blotched and unreadable. Close inspection showed it was a problem inside the unit.

The Sears warrranty was only 90 days and the VOM was 6 months when opened so Sears refused to cover it even though they admitted it was an internal leakage and that it came out of the package like this.
One more reason Sears can go to hell.

In case your multimeter is a Fluke . . .

Contact them. They will calibrate it for free. I’ve done it before, and they returned my meter in perfect working order. In my case, it was reading incorrect resistance

Does it matter what model or the age?

It is a “Sperry” , but I will check to see if they have the same policy.

Yosemite

They do not cover calibration, and I doubt that i have the receipt anymore.

Test leads, fuses, batteries and calibration are not covered under any implied warranty. “Lifetime” of products that are no longer offered by Sperry will be either repaired or replaced with an item of Sperry Instruments choice of similar value. Lifetime is defined as 5 years after Sperry discontinued manufacturing the product, but the warranty period shall be at least ten years from date of purchase. Original proof of purchase is required to establish original ownership of product.

Yosemite

odd. original alt had no output when tested and your vom flaked out when you tried to test new alternator. its a convergence of the stars. just like the vikes will win today.

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As far as I know, it doesn’t matter

When I contacted them, they didn’t ask too many questions. They certainly didn’t ask how old the meter was. I know it was probably over 10 years old at the time, though

When I bought it, I was debating what brand to buy. I finally decided on Fluke, because my old trainer from years before swore by them, and because it seemed to be a “standard” for many industries.

Several years later, a few of my colleagues had problems with their Snap On and Blue Point meters, which in some cases were just as expensive as Flukes. But when they inquired about a “lifetime warranty” they were told to go pound sand.

As long as the Vikings WIN !

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@Cavell misread the original post.
The old alternator was putting out 18.9 volts when I tested it at the charging post on the alternator.
The two parts stores said that it was not putting out anything. That’s why I went to two stores, I figured that the first place didn’t have the case grounded good enough.
I think both places just wanted to sell an alternator.

Yosemite

Thanks for the update OP. I have a meter like that; I put a little piece of tape on it reminding me it reads 50% low on AC voltage. Goes to show, it’s always something :wink:

So George?

That tape on your meter is your calibration certificate?

You’re a riot!

Tester

Yes I have even pressure gauges, now I like to use good ones, but can’t seem to throw away the old ones that may be 3 to 5 psi off, and put a label on them indicating ±psi

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