My dad says it did not happen before to his Maxima, but now it does. Is that normal... for the engine to stall when you disconnect the battery cable?

 

Yeah it'll stall if your alternator isnt working

 

That's not normal, you shouldn't notice a difference in idle. You've got an alternator or other electrical issue going on.

 

Most likely dead alternator. Are the brake and battery lights on? If so, then it's a dead alternator. That, or something happened to the serpentine belt.


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The brake and battery lights are OFF. The belt is fine too. We've been driving the car in this condition for months. If alternator was bad, wouldn't it stop charging the battery? But the battery is still fine.

Can a bad ignition starter switch have anything to do with this issue? I got a new switch, cause the old one would turn the radio/clock off, and one would have to wiggle the key for them to turn back on. Haven't tested out disconnecting the battery yet though.

 

Which terminal are you taking off. If its your positive cable your alternator is shot.

Get this fixed/checked out your battery is basically doing all the work and you will be stranded one day. Don't want that happening.

 

Why are you doing this in the first place?

 

Good question

 

Positive/negative, doesn't matter. Either cable you remove you're electrically isolating the battery from the vehicle.

 

Have you checked charging system voltage with the engine running? What about alternator amperage output? The alternator may be able to charge the battery up over time, but not be able to provide the current required to run all 6 coils and injectors, the fuel pump, ECU, etc by itself.

If you don't have the equipment, take it to a shop for a starting/charging system check (with a current reading, any decent charging system tester has provisions for this).

FWIW, this is a poor method to use as a test. Disconnecting the battery leaves no 'buffer' (for lack of a better term) for any electrical transients that may occur (ever see a voltage waveform from an ignition coil? A 200v spike isn't unheard of). Will this cause damage? Rarely. Is it a good idea? Not at all.

 

The car has been having a lot of cylinder 1 misfire, mostly at idle/red lights, at higher RPM it works fine... reading the blinking check engine light gave the code 0608. Could that be because of the bad alternator?

The car had a lot of engine shaking on the freeway a few months ago, as if it was about to stall, when he got off the freeway and was driving on residential street the car stalled. Then got the car jump started and got home and got new battery, and the car has been working since then. Is this also a sign of bad alternator?

Is it possible to test the alternator without taking it out using a multimeter?

 

A bad alt could potentially cause a P0301, but unlikely just for one cylinder.

Yes, it is possible. Again, have you checked charging system voltage?

 

No, how do we do that?

 

Do you have a DVOM?

 

Your alternator is obviously not dead because it still charging somewhat. Sounds like you ground issues.

Start by testing the insulated circuit (positive)
Battery positive+ to alternator battery terminal. Check you voltage drop with headlights on at about 2k rpm should be no more than .5v drop.

Negative circuit
Battery Neg. - to alternator housing. Again 2k rpm headlights on(or applya 20a load with VAT machine).
No more than .2v

 

We got one that only measures voltage... the other settings on it are broken.

 

The easiest way to test your alternator output is to take it to your local OReilly or Autozone and have them test it. Free, fast and easy.

 

The voltmeter part is all you will need.

Before you start the car, a fully charged battery will measure 12.3 to 12.5, give or take. After you start the car, the voltage should measure 14 to 14.5 volts.

 

Did the voltmeter test by hooking it up to the + and - on the battery. With the engine off, it was 12.65, with the engine turned on and at idle it is 14.13... adding a few revs goes up to 14.20.

Does this mean for sure that the alternator is working fine?

 

Sounds like your altenator is o.k if it's 14.20v when running. You can also see what the voltage drops to when the battery is under load by putting the multi meter on it and check it while you have someone crank over the engine.

 

The way you describe the cylinder one misfire sounds like it may be a bad coil.

 

The misfires are most likely due to bad spark plugs. We got some cheapo ones recently. Replaced the plug in Cylinder 1 with the old Maxima one, and the misfiring stopped... happens very rarely now and the 0608 code is gone. I'm gonna buy those NGK plugs that the user manual recommends, and replace all of them.

 

Not for sure, no. Again, you need to have a proper charging system test done.

 

How do I do the proper charging system test? Take the alternator to AutoZone or OReilly?

Or do I do the test that 4th gen maxi mentioned... measuring volts at 2k rpm and turning the lights on?

PS: I appreciate everyone's input in this thread! And thank you pmohr for all your YouTube videos... helped me and dad a bunch!

 

I would suggest starting the car, turn off all accessories including radio and all lights. Disconnect the positive wire and if the car stalls, that alternator is on the way out. Your car is suppose to idle with just the alternator. It may not be the correct test but how long is the alternator in there? Does it have the green paint mark on it?

 

Take the car somewhere that does a proper charging system test. If you go for the free test at a parts store, likely all you'll get is a voltage reading while the car is running. You want to see an alternator current output reading.

 

Not just the altenaor. Take the car to a shop to test your charging system if your unsure how to use a battery tester or multimeter. They shouldn't gouge you or charge you much if anything to test it.

 

Just drive the car to advance auto or autozone and ask for an alternator test. They'll tell you if its good or bad

 

you're absolutely wrong removing the positive cable should let the vehicle run on the alternator circuit there are only a few cars that actually have the ECU powered through the battery I am a mechanic and I've had hundreds of cars from the 1970s up till 2020 that I would remove the positive cable to test for alternator failure when I was in the field I obviously do this with a multimeter at my shop

 

Hey Newbe........
Please look at the date of the last post.
it's from 2013.