charging issues on 1991 Honda accord se

[kris]

Having charging issues on 1991 Honda accord se automatic 2.4L f22a engine.

After driving for a few days to a week I have problems starting. The starter turns weak or not at all. If I charged the battery all was good. I have had this issues for a while It got a new battery as I thought that was the issue. In my defense the batter was 8 yrs old lol. I the car was parked for a few months. now I have same issue.

Tested alternator on car It was only putting out like 20 amps. Pulled off tested it at the store and It tested bad on their tester. Replaced the old alternator. It was bad, had 200k miles on it. The New alternator tested good on their tester. I always have them check I have gotten bad ones before.
I charge up my battery and installed new alternator.

Now I am Having same issues in a week or so the battery is low causing starting problems. Starter not wanting to turn over or is weak to turn. I checked the amps out with the load tester I am only getting ~40 amps at 2k rpm (did this 3 times once with lights on. Two times with them off still around 40 amps). It should be getting 80 amps. Pulled it off tested it again at store it passed. It has a new belt, it is tight enough checked with a gauge, and connectors or clean at battery and alternator.

I’m thinking I have ground issues. I will be cleaning grounds etc… looking for tips, tricks, advice or if someone had same issue that can help.
Thanks for your time.

Edit :

I may have a fundamental misunderstanding of car electronics. When I tested for continuity with my DMM I get less than 1 ohm from the negative to the alternator housing . I then by accident checked and had less then 1 ohm from positive to alternator housing. I checked the two battery post and they had continuity. Is this right? seems like it should not have continuity and that it would be shorting out. It was the same when i test for continuity to engine and body, is this right??

Edit 2: your not supposed to use an ohm meter with a circuit that has power going to it. need to remove battery to test. good question is why would there be continuity with power but thats not a car question.

Topic

[college man]

Do a voltage test. more in this link.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems?start=2#ChecktheBattery

[EricTheCarGuy]

Checking the battery is always job 1 when dealing with electrical issues of this type. I would make sure that is good first before you proceed. It should have 12.6V and not fall below 9v when load tested. If it can’t pass that, start with a battery.

More info here.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

And here.

http://www.ericthecarguy.com/faq/solving-automotive-no-start-problems

Good luck and keep us posted.

[kris]

Solved: The battery is less than a year old. I tested it anyway. It passed all the test you showed with voltage drop. I knew it had to do with charging. The alternator should put out around 80 amps I was getting half that. I tested all my wires top side for shorts and high ohms. They all passed. everything was grounded.

The issue was the main ground to the transmission. It is the biggest one of them all and is also how the alternator grounds to the battery, through the engine. altho it did not have high ohms, the last 6″ or or so was badly corroded due to Honda not putting insulation on it not sure why. I pulled it off cleaned it up and put it back on.

amp out of alternator went from 30-40 to 79-80 amps. electricity travels on the outside of the wires not on the inside. with it corroded it reduced the maximum amperage of the wire. like trying to get all 100 gallons a minute of water from a 1″ pipe when you put a 3/8″ pipe outlet on the end of it. you can only get about 50 gallons.

grounds have to be good and have be able to carry just as much amps as the main wire as they complete the plumbing.

Thanks for your time again guys.

[college man]

Glad you got it. 🙂

[Author]

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