Do I need a new battery or is it deeper?

thatsnninety5 · Dec 23, 2024

I had that problem with my P0320 with the crankshaft, whole time it ended up being the alternator weirdly enough so I replaced that, now im having an issue where my battery is so dead it doesnt show any dash lights, the door doesnt ding when my door is open nor does the interior light come on. While driving the battery is fine but this minute I shut the car off its like a shot battery, and ive got it jumped but the only way for the other car to give enough power to jump my car is it they stay around 3k RPM while I try to start it and it still struggles to start
PICTURE A IS WHILE DRIVING
PICTURE B IS ENGINE OFF, KEY IGNITION ON
PICTURE C IS BATTERY VOLTAGE

A

B

C

Terrorist 5.0 · Dec 23, 2024

If I were you I would start checking the basics. Check your connections to the battery. Are they clean and tight? If so, then start following the wires that come out of it. On my 1995, there is the starter power wire, which provides power to the starter, and the fuse block power, which provides power to the fuse block. The ground side is for grounds. I had an issue where I would start the car, and after shutting it off (if it didn’t shut itself off) it acted like it didn’t even have a battery under the hood. My issue was simply solved by cleaning my battery connections and replacing a corroded ground strap from the engine block to the chassis. I’m not sure what was the actual issue, but I just found these things by looking. On a side note, don’t drive the car like this. If your connections are bad and the battery is somehow getting isolated from the cars electrical circuits, you could cause damage to a lot of things. Even though the gauge is reading good, it is best not to just trust it. The battery on a car is like a capacitor in that it can suppress voltage spikes and stabilize output from the alternator. Without it, the alternator will be sending some ripple voltage, and the voltage regulator will go nuts, pegging up and down to try and compensate. It can seriously damage a lot of electrical components in the car. Just look around, cleanup whatever you find. You will be surprised what you will find sometimes.

RAU03MACH · Dec 23, 2024

check battery cables + - and connections on cables

ttocs · Dec 23, 2024

IMO the battery would be the easiest to test and I would start there. Remove it from the car and connect it to a charger or take it to vatozone and leave it with them for a few hours. They will charge it and run a test right off the charger, but have them run it again a couple of hours later when you pick it up. I have seen batteries fresh off the charger test good but then when you do not have them hooked up to anything they start to drain the voltage.

Now while it is out it would be really easy to test the resistance of the grounds and the power wire to the alt with a meter, I would do that if the battery tests good before I put it back in.

thatsnninety5 · Dec 25, 2024

ttocs said:
IMO the battery would be the easiest to test and I would start there. Remove it from the car and connect it to a charger or take it to vatozone and leave it with them for a few hours. They will charge it and run a test right off the charger, but have them run it again a couple of hours later when you pick it up. I have seen batteries fresh off the charger test good but then when you do not have them hooked up to anything they start to drain the voltage.

Now while it is out it would be really easy to test the resistance of the grounds and the power wire to the alt with a meter, I would do that if the battery tests good before I put it back in.

How would I test the resistance of the grounds? Is that with my multimeter?

ttocs · Dec 25, 2024

yes. Set the meter to the omega(the horse shoe/resistance) and then simply put on lead on one end of the wire, and the other meter lead on the other end of the wire. In a perfect work, there would be absolutely no resistance and it would just read 0 ohm, realistically there will be a slight resistance on any wire, but we want them as close to 0 as possible.

To test if you have the meter set up right, once it is in the proper settings if you touch the leads together it should go from some reading showing infinite resistance (------- or something) and when you touch the leads it should again show almost 0 ohms resistance.

Terrorist 5.0 · Dec 29, 2024

Did you fix it yet? What was your fix?

Miltoid · Dec 30, 2024

To test the ground's resistance, put the meter on 12v. Probe from engine to neg. battery post. Turn on the headlights. Do you see voltage? If so, you have a bad connection somewhere, such as a bad ground cable. Ohms is not a valid test.

ttocs · Dec 30, 2024

I can see how your test would work but to say testing the resistance of the wire with the ohm meter isn't valid is funny. We are searching for corrosion/resistance, exactly what it is made to do.

Miltoid · Dec 30, 2024

With a heavy cable, the resistance won't show up until it has a load on it. Using an ohmmeter can lead you down the wrong path. MAGA

ttocs · Dec 30, 2024

out of curiosity then, what gauge wire is too thick to measure resistance on?

Miltoid · Dec 30, 2024

While you are at it, check the voltage at the battery posts. If it is below 12.4v, the battery is dead or bad. Another test is to turn on the headlights. If they come on, hit the starter. If they dim significantly or go out, you have a bad connection.

Miltoid · Dec 30, 2024

ttocs said:
out of curiosity then, what gauge wire is too thick to measure resistance on?

Any gauge, depending on the nature of the bad connection, it may or may not show resistance. Lets say you have an 18 gauge wire that is cut, accept for one strand, if you check the ohms you will see very little resistance, but the wire is bad. The test is not reliable. Save yourself some heartache.

ttocs · Dec 30, 2024

Seems to me if a perfectly good wire was cut to where only one strand was still connected that you would still be able to send 12v across it. The current would be limited for sure but you can put 12v across a 24 awg wire, or you can put it across a 0 awg and as long as the resistance of the wire is good the V drop is low. Now if that strand was corroded, then it would limit the voltage because of the resistance but you should be able to measure it if it is significant enough to cause problems like we have here.

Miltoid · Dec 30, 2024

Could you put 12v through it if it's hooked to a headlight? Every wire is connected to a load. If you put voltage to a wire to ground as you say, it smokes. Give it up you're wrong.

ttocs · Dec 30, 2024

so again, that would be because of the current the light might possibly draw but your telling him to measure voltage. As you said if this was the case it would smoke that single strand, in which case a resistance test would then work just as well as a voltage test but that is not the case we are working with. I am not saying your wrong with the case at hand or with your instructions, just that I am not wrong either. It is common to use the ohm meter when measuring resistance....

Miltoid · Dec 30, 2024

What is the purpose of a wire? It is to move current with the least amount of resistance to the intended load. Again you say sending 12v through a wire. To do that you would connect it to a battery and it would turn into a heating element, for a second.

ttocs · Dec 30, 2024

you could use a coat hanger or part of your exhaust and it would have the same effect I am not sure what your point is? But honestly I don't care anyone with half a brain understands what resistance is and the tools to measure it so it is not worth my time.

Terrorist 5.0 · Dec 31, 2024

Yikes, this post went downhill fast. I just wanted to see what the issue was in this case lol

ttocs · Dec 31, 2024

hopefully the op was not overloaded. His method would work and it is a way to test it with the battery in the car. I still think the battery is probably the problem and it needs to be tested, but while it is out charging/testing it is easy to check the cables with an ohm meter as it is designed for it.

I will say again if you do this to leave the battery off the charger for an hour or two before they test it or it can test as good right off the charger but start to lose voltage not connected to anything and an hour later tests as bad. I normally just drop it off at autozone and tell them I will be back in a little bit and then I have them test it in front of me when I come back later to ensure it is good.