97 chevy electrical question

[K5Titan83]

okay I have a 1997 chevy 1500 single cab shortbed with a 4.3L any way I was leaving oriellys, and I noticed a slight loss of power for just a moment then it went back to running fine. but I noticed my volt gauge was kinda bouncing around a little. got her home, shut it off and tried to start it and there was nothing no lights on the dash the door dinger went off and when I turned the key it didn't do anything so I came back to it bout an hour later with a voltmeter, battery had a charge, tried starting it and it fired right up. so I checked the battery while it was running and it was holding a good charge. so then I shut it off and started it like 3 times and on the 4th time it did it again the door dinger went off and it wouldn't do anything no dash lights nothing. even when it was running there was no check engine light or anything. I did notice my radio was reset as well.

so I assume the battery is fine cuz it was holding a charge, and the alternator is good. im thinkin its either some wire going to the starter might be loose? or something in my steering column?

any other ideas for me to check tomorrow?

 

[jekquistk5]

If you lost presets on the radio the always hot power was lost. Check both battery posts and the main cable from the starter to the battery.

 

[K5Titan83]

If you lost presets on the radio the always hot power was lost. Check both battery posts and the main cable from the starter to the battery.

the posts on the battery are tightly connected. tomorrow that's what I thought id check the stator wire I think its called?

 

[Fordum]

the posts on the battery are tightly connected. tomorrow that's what I thought id check the stator wire I think its called?

Don't forget the other end of the battery cables, plus the other half of the battery circuit.

The ground wire.

The door dinger going off when it was not supposed to sounds like the system was trying to get a ground though it.
Make sure the ground cable from the battery is hooked to something solid, and if you have the small wire from the battery ground to the body, make sure its good.

If all seems well, then turn on all the electrical loads you can without the engine running.
Lights, fan, put a good load on the system.
Measure from post to post on the battery.
If its good, no lower than 12v, then set the meter on the lowest DC setting. Measure from a battery post to the clamp that is hooked to it.

Ideally you should see zero volts, but a few milivolts are OK. Anything approaching a volt is a bad connection no matter how clean and tight it looks.
Check both terminals. If you have less than a 1/10 of a volt with a heavy load, then the connections are OK.

 

[AR_K5]

Picking at straws

I hate those trucks.

Make sure the main hot wire in the fuse block has a good connection.
Check the wires on the alternator.
Make sure the ECM fuses are clean an pressed in all the way.

You should be able to completely remove the battery with the engine running if the alternator is working properly. So it's not likely to be the battery. It's most likely a connection issue somewhere.

Try moving the tilt steering.

 

[Fordum]

You should be able to completely remove the battery with the engine running if the alternator is working properly

Man, Please don't do that!!

That was good quick and dirty trick to test your alt/gen back in the days of points and no electronics.
Nowadays its a great way to fry lots of electronics in the truck.

When you remove the battery, the alternator may lose its ground reference. Without a ground reference, or the load of the battery, the output of the alternator may float up to several times its correct voltage.

I have seen voltages in the 40 volt range when the voltage regulator loses its mind.
NOT healthy for onboard electronics.

 

[AR_K5]

Relax

I wasn't suggesting he do it, I was just saying a bad battery or terminal won't cause a loss of power while the truck is running. The alternator provides more than enough power to operate the electronics and charge the battery. As stated above and below it can cause more problems.

Don't hang on every word so much.

 

[Stomis]

Man, Please don't do that!!

That was good quick and dirty trick to test your alt/gen back in the days of points and no electronics.
Nowadays its a great way to fry lots of electronics in the truck.

When you remove the battery, the alternator may lose its ground reference. Without a ground reference, or the load of the battery, the output of the alternator may float up to several times its correct voltage.

I have seen voltages in the 40 volt range when the voltage regulator loses its mind.
NOT healthy for onboard electronics.

Indeed. Theres also the fact that alts actually necessitate juice to make more of it. Pulling the battery will leave the alt referencing capacitors in everything electronics in the car...

 

[AR_K5]

Ok now that I've been well torched over a miss understood statement.

I've always felt I had a pretty good grasp on DC electronics. And since I've attracted the the attention of a couple of electronic engineers, I'd like to ask a couple of questions.

The way I understand it, the battery does only 2 things. Start the car and power the electronics while the alternator is not turning. When the engine is running, the alternator takes over providing electricity to power everything and charge the battery. It job of the voltage regulator is to regulate (keep constant) voltage as the rpm of the engine changes. If the battery is fully charged the amps being drawn from the alternator will decrease as will the load on the engine.

If the battery is nothing more than a tank that TAKES energy FROM the alternator and stores it, why would the voltage regulator stop maintaining a constant voltage if the battery were to be disconnected and the cables were not allowed to short circuit? How would this not be the same as a fully charged battery?

All of the electronic operate within a voltage range and and draw amps based on that voltage input in order to maintain the required wattage. If the voltage increases, so long as it stays with a usable range, the amp draw will decrease. If the voltage decreases amp draw increases. To total power required to operate is measured measured as watts (amp x volts = watts).

I've heard this myth since the 80's and have yet to see a car's electronics fried over someone unhooking a battery. Not saying, it has never happened, I've just never been able to confirm the myth.

 

[rampage]

And since I've attracted the the attention of a couple of electronic engineers, I'd like to ask a couple of questions.

Actually, more than a couple.

All of the electronic operate within a voltage range and and draw amps based on that voltage input in order to maintain the required wattage. If the voltage increases, so long as it stays with a usable range, the amp draw will decrease. If the voltage decreases amp draw increases. To total power required to operate is measured measured as watts (amp x volts = watts).

Not true. Power is just a measure of how much current is drawn at a given voltage, it doesn't remain constant. In a standard DC circuit what remains constant is the overall resistance of the circuit. Ohm's law states that V=IR, so if you increase the voltage the current increases proportionally.

 

[diesel4me]

The altenator cant magically make electricity from thin air,unlike a generator,it actually just boosts up the current it gets from the battery--it needs 12V fed to the field coils to produce a charge....however once it has started charging,its often possible for enough residual magnetism to remain in the field coils to keep it charging,even if you dissconnected the battery..

But without the "sensing" circuit in the regulator detecting any voltage with no battery connected,the regulator will assume the battery is completely discharged, and will "tell" the altenator to put out maximum voltage and amperage ...this can pop the diodes in it and fry todays sensitive electronics..years ago it was not such a big deal,at most all that usually failed (and not often) was the diode trio in the altenator...maybe your fancy aftermarket stereo too,if you did the "remove the battery cables" test..the battery itself acts as a electrical shock absorber in a way,without it in the circuit current spikes and surges occour..

A better but crude way to see if an altenator is charging without damaging it is to put a steel screwdriver or similar object near the rear bearing on it--it will attract the screwdriver with a strong magnetic pull if its working--be careful not to short the main output terminal on the altenator to ground while doing this..I do this if I have no voltmeter handy..

 

[Fordum]

I wasn't suggesting he do it, I was just saying a bad battery or terminal won't cause a loss of power while the truck is running. The alternator provides more than enough power to operate the electronics and charge the battery. As stated above and below it can cause more problems.

Don't hang on every word so much.

Well, I said Please..........

Actually, given my mental state here in the third week of turkey season, I was pretty much nodding off when I read that.
I just saw "remove battery" and "engine keeps running", and it triggered a stock response.

As for your follow-up question, give me a little while. I'm pretty sure I can explain it, but I am wiped right now.
If any of the other techs wants to do the honors, feel free.

Normally I put most things on hold during this time, but a big land deal would not wait, another guy needed some control boxes designed and built, they have started to have a Pompano run in Mexico Beach and one of my other customers managed to break a $200K machine which needed to be fixed before the factory rep could get there.

On top of all that, I foolishly started back in on my personal quantum physics theory.
An article on the delayed reaction version of the two slit experiment caught my eye, and I was off.

Quantum Physics and Turkey Hunting do not mix well...........

Turkey Hunting is harder.........

I should not be up now, but I ate too much Bar-B-Que for supper. That caused me to drink too much Coca-Cola.
That cause me to have to get up and go whiz.
And now I can't sleep.

I guess I will just wander aimlessly around the house until I either fall down asleep, or the alarm clock goes off......

 

[AR_K5]

Not true. Power is just a measure of how much current is drawn at a given voltage, it doesn't remain constant. In a standard DC circuit what remains constant is the overall resistance of the circuit. Ohm's law states that V=IR, so if you increase the voltage the current increases proportionally.

You just talked yourself in a circle. Now I'm even more convinced it's a myth.
You just said the same thing I did with different words. But never tried to answer my question

Power
The product of applied potential difference and current in a direct-current
Current
-a flow of electricity through a conductor; (can be measured in volts or amps)
Volt
-a unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt
Ampere
-a measure of the amount of electric charge flowing past a circuit point at a specific time
Watt
-a unit of power equal to 1 joule per second; the power dissipated by a current of 1 ampere flowing across a resistance of 1 ohm
Ohm
A unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt across its terminals.

Volts x Amps = Watts
Volts / Amp = ohms

Any two of those measurements can be used to get the other two.

My misstatement was this

If the voltage increases, so long as it stays with a usable range, the amp draw will decrease. If the voltage decreases amp draw increases To total power required to operate

What I meant to say was.
If the voltage increases, so long as it stays with a usable range, the amp draw will decrease. If the voltage decreases amps would have increase to maintain enough power to operate.

I'm having to punch all of this out on a iPhone about every third word gets autocorrected, cut me some slack.

 

[AR_K5]

The altenator cant magically make electricity from thin air,unlike a generator,it actually just boosts up the current it gets from the battery--it needs 12V fed to the field coils to produce a charge...

No kidding? Why do you think it has a belt attached to the motor.
They both convert mechanical energy to electricity. You are thinking of a power converter, I'll just ignore the rest.

http://www.differencebetween.net/object/difference-between-alternator-and-generator/
Summary:
1.In an alternator, electricity is produced when a magnetic field spins inside the stator (windings of wire). On the other hand, the armature or the windings of wire in a generator spin inside a fixed magnetic field to generate electricity.
2.Alternators conserve energy by using only the energy that is needed. Generators use all the energy that is produced.
3.Alternators produce voltage when needed and generators produce voltage at all times.
4.Alternators generate a higher output than generators.

 

[Stomis]

No kidding? Why do you think it has a belt attached to the motor.
They both convert mechanical energy to electricity. You are thinking of a power converter, I'll just ignore the rest.

http://www.differencebetween.net/object/difference-between-alternator-and-generator/
Summary:
1.In an alternator, electricity is produced when a magnetic field spins inside the stator (windings of wire). On the other hand, the armature or the windings of wire in a generator spin inside a fixed magnetic field to generate electricity.
2.Alternators conserve energy by using only the energy that is needed. Generators use all the energy that is produced.
3.Alternators produce voltage when needed and generators produce voltage at all times.
4.Alternators generate a higher output than generators.

Listen Im no electrical engineer alright. I think you're getting a little butthurt for no reason here. No one got mad, or accuse you of trying to sabotage the guys truck or some ****. Fordum just stated that its not a good thing to do that and he just happens to be, well elaborate. For all you know the OP may have misread what you typed also and said hmmm lemme go try that...

So now that we've taken a step back, I will once again go on record saying I am no electrical engineer but I do happen to know that an alternator takes juice, even if its a tiny bit, to make juice. Where as a generator will make juice from scratch. If you want to argue about equations and theory have at it but I know this to be fact.

 

[AR_K5]

I'm not butt hurt, or mad, sorry if I gave that impression. Just trying to clear up a simple misunderstanding. It was late and I was tired.

There is nothing on this planet that makes electricity from scratch, NOTHING. Not even a nuclear power plant. An alternator simply won't charge a battery from 0% because it doesn't know it's there, but it will charge a weak battery. If it was simply ramping up volts, that's the same as putting a pin point nozzle in a garden hose, it would move faster but volume (per second) would decrease. Power would only be going out, and you'd have to charge your battery at night.

Sorry but your "facts" are not correct.

Shall we start another forum so we can get back to helping the OP now?

 

[AR_K5]

To the OP. I apologize for wrecking your thread. But the only reason your volt meter would have been bouncing is if the overall resistance in the circuitry of in the vehicle had changed.

Meaning something either momentarily shorted out allowing one of the circuits to short (dump massive amounts of power). Or something that requires a lot of wattage is losing power momentarily. If no fuses were blown your next step should be to check any circuits without fuses (ie the make sure the big hot wire isn't rubbing against the frame or exhaust, and all connections are clean and well connected)

For it to cause a loss of power in the engine, it would have to be either some part of the engine management, fuel delivery, or ignition system, or a direct short of the main power supply cables which would dump all electrical power directly into a short circuit (the frame/engine)

Since the entire electrical system (engine and body) was failing, and there was no smoke or blown fuses, it's likely a bad connection somewhere between the battery and the fuse panel. That's why I suggest you try moving the tilt steering (if so equipped) because sometimes that's where those problems arise.

Best of luck to you

As Ryoken would say: you need to isolate the problem before you waste your money.

 

[rampage]

Current
-a flow of electricity through a conductor; (can be measured in volts or amps)

No, current is measured in amps. Voltage is measured in volts.

What I meant to say was.
If the voltage increases, so long as it stays with a usable range, the amp draw will decrease. If the voltage decreases amps would have increase to maintain enough power to operate.

How did I state the same thing as you, I stated the complete opposite. I think what you're thinking is that the wattage that's written on a device remains the same, like a 65W headlight or a 100W stereo. That power measurement is only true for the recommended voltage. I'll state it again, if you increase the voltage applied to a device you'll increase the amperage draw also. Let's take a really simple circuit, like a 12V battery and a 4 ohm resistor. Using ohm's law, the current is 3A, so the power dissipated is 36W. Let's double the voltage of that circuit. Now the current is 6A and the power dissipated is 144W. So increasing the voltage increases current and increases the power dissipated. There is no difference between this simple example and a more complex one. Prove this wrong and I'll ask for a refund on my degree. You need to use ohm's law first to determine either V, I, or R then you can use P=IV to determine the power consumed. You're using the equations backwards.

Now I'm even more convinced it's a myth.

Since you believe everything in that link you posted then you must have missed this:

"There is another difference between generators and alternators when it comes to charging. An alternator will not charge a dead battery and if you do try to charge it, there is a possibility that it will burn out. A generator, however, can be used for charging a dead battery."

Dead battery = 0V = no battery present.
Maybe this would be a good myth for you to submit to Mythbusters, or better yet try it out on your car and report back to us.

Done hijacking this thread.

 

[K5Titan83]

haven't been able to read all the comments for a while but I finally had the chance its been an interesting read haha. but anyway what I found was everything on the starter was tight, everything in the fuse box was fine BUT the wire going from the battery to the alternator had a bare spot it wasn't touching anything but I replaced the wire and I noticed the connections from the battery were kinda half assed and were starting to come loose so I fixed all the connections the right way and made sure and tightened them up so nothing is or will come loose again. so far the truck has ran fine nothing out of the ordinary drove it around all day and it was great. but I think this was to easy of a fix so im waiting until it happens again haha. im sure itl pick the most inconvenient time

but the small amount of arguing gave me some more insight into this stuff haha so I thank you all for that iv never been any good with electrical stuff.

 

[AR_K5]

Hey, I learned a few things myself along the way while trying find references and better ways to explain more clearly how alternators work, and dispell myth about unhooking the battery. It was fun.

In your case a poorly connected alternator wire would have caused the alternator to kick on and off (load and unload) switching the ignition system and whatever else you had on, back and forth between the battery and alternator. The sudden drop in electric power when the alternator kicked off caused an insufficient (if not delayed) spark to burn all of the fuel. You didn't get a code from the ECM because the connection was restored before the voltage dropped low enough to trigger the code.

I hope your rig doesn't give you any more trouble. It's amazing how many good parts get replaced over bad connections. It never hurts to just unplug a suspected bad electrical part and scrape the oxidation off the connections and try again (but a multimeter always works best).