91crxSi

I have been problems with my car, the situation at the moment is this.

When I use a multimeter to measure the voltage of the car, it is not at a steady 14v, like its supposed to be, when the car is on. My friend's s2000 maintains a steady 14 v while on, and the same goes for a nissan altima that I tested.

The car, while on, is supposed to maintain a constant voltage of 14v.

I checked the voltage last night and it was around 13.8, and it dropped to 13.5 with the accessories on. I checked it just now, and it was at 14.2-14.3. When I turn on accessories (like a/c, headlights), the voltage moves around, while on my friends car, it maintains a steady 14v. (this is all when the engine is on)

I have a new (used) alternator in the car. I had the alternator tested and it works perfectly. On the machine it was tested on, it would maintain the voltage steadily. My last alternator was overcharging (it had bad diodes), and melted a battery.

I believe that the old alternator broke something.

Any ideas?

turbo_slug

put your multimeter in AC mode then measure the voltage while the car is running. it should be close to 0Vac. if not, your alternator diodes are toast.

as for 636 CCA, it's high for a group 51 battery but low internal resistance isn't a bad thing

91crxSi

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91crxSi

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SUPERAnimal

So what exactly is happening since the second alternator was installed? Are you destroying batteries? or melting wires?

91crxSi

with the second alternator, the voltage is not held stable at 14v while the car is on. the voltage acts exactly the same, it ranges between 14-16v, and when the accessories are on, it stays around 14.5.

the alternator i was using for last few months was checked yesterday, the diodes are fine, and it does charge

last week, i was driving and the car was acting like the battery was dying. i ended up having to push it home. at one point, i moved the terminal connectors around a bit and it turned back on, but it died on the way home.

the EPS light had come on, and the battery light too. the battery needed to be recharged. I went on vacation for a week, and the battery needed to be recharged again.

I think the ecu might be damaged. i plan to swap it out and use a multimeter to see what the problem is.

could there be other issues?
there is supposedly (based on the service manual) a voltage regulator inside the main underhood fuse block. I could not find any corresponding fuse or relay though, and i believe it might be inside the fuse block, which I can't open up. I dont have access to a service manual anymore...

any ideas?

91crxSi

i checked the ground wire that connects to the alternator, and it has this green greasy stuff all over the wire.

i did have to use a rotary tool to take off the nut on the ground of the alternator (it was cross threaded on there), so i dont know if any of the spraks would have caused the greenness.

SUPERAnimal

So just to clarify since adding the second alternator the only problem that you are having is that the voltage when the vehicle is running is fluctuating between 14 and 16 volts? Nothing bad has happened since the second alternator you are just worried that the voltage might be too high?

91crxSi

yes, the voltage should not be fluctuating at all. when i changed my battery the first time around, i checked the voltage with the old alternator, and it does the same thing as the new alternator does. my friend's s2000 holds a steady 14v while on, just like a nissan altima i tested as well.

i've had problems with the steering skipping, as i described above. this is a symptom of too much voltage in the electrical system, which would typically be due to a damaged alternator overcharging the system.

given that i have the same voltage problems with a good alternator, i believe that the cause of all this is what led to my previous alternator being damaged, and the battery meltdown.

and, i had the car turn off on me recently. the steering was messing up on me. the voltage is not being properly regulated.

please help

SOHCmyDOHC

you try swapping alternators with your friend?