Hello All,

I'm having a very weird problem with my 2002 Z24. I woke up one morning and started up my car but the car had no power. Absolutely no power, the dome light in the car wouldn't even turn on. I get a friend's car and jump start it and it starts up. I drive it all the way to work and when I go for lunch, again, no power. My first thought was the battery was bad since I'm able to drive the car with no problems after a jump start so I go and get a new battery. Cars starts up and everything is good again. Next day, same thing happens, car has absolutely no power and won't start. I go get the battery checked and it checks out ok. I put the battery back in and run the car for 10 minutes with the headlights on, the dome lights on, the heater on, and the stereo on. No problems. Now my first question is:

1. What can the problem be? If it was my alternator, shouldn't my car shut down once the battery gets drained?

2. Can I purchase any multi-meter and check the voltage of the car while it's running? Should check out to about 13.5 - 14.5 while running. The guy at the store tells me I would blow the $50 multi-meter he was showing me if I checked it while the car was running. He said the max voltage on the meter was 12v and only professionals can check any voltage higher. I question this since a friend of mine checked my old neon with the car running using a cheap $15 multi-meter and had no problems.

I'm sure someone out there can enlighten me.

Thanks in advance,

I forgot to mention that the second time the battery died before I purchased the new battery, I tried to jump start it again but it didn't work. Had absolutely no power even hooked up to another running car.

guy at the store was a moron. the meter or the packaging should say what the range is for a meter. most decent meters will read up to 1000 volts. I got a very nice fluke digital multimeter off ebay for about a hundred bucks


You'll never touch God's hand
You'll never taste God's breath
Because you'll never see the second coming
Life's too short to be focused on insanity
I've seen the ways of God
I'll take the devil any day
Hail Satan

(slayer, skeleton christ, 2006)

Yep,

I figured that out after reading it up on the internet. The guy was a total moron. Anyways, I went out and bought a $40 multi meter that has a max voltage of 1000 volts dc and checked the battery with the car off. Checks out at 12.86. Then I started up the car and checked again. Checks out at 14.8 - 14.9. Is this a little high? Should I be concerned with the alternator? I'm thinking this should still be ok and believe that it was just a connection or ground wire issue somewhere.

both readings sound normal for a 6 cell lead acid battery (car battery). I would take the alternator to autozone to have it checked by them, but at this point i'd suspect a faulty alternator or wiring


You'll never touch God's hand
You'll never taste God's breath
Because you'll never see the second coming
Life's too short to be focused on insanity
I've seen the ways of God
I'll take the devil any day
Hail Satan

(slayer, skeleton christ, 2006)

OK, the alternator's voltage regulator might be broken, since 14.9V at the battery is high. You should have mid 13V with the car running, give or take alittle bit. Also, the reason you are having starting problems is the battery is either 1) being drained (dome light on, for example) or something aftermarket---your registry isn't filled out so I don't know anything like that. Maybe a sub or amp is pushing too much. Also, the battery by now is probally deep cycled, a good idea would be to replace the battery after you fix the problem. It's current life is dramatically reduced.

Sam


Ban low-performance cars, not high-performance ones.

oh jeez, didn't really notice that......14.8V is a little high.....a typical lead acid battery shoudl have between 2.0 and 2.2 volts per cell....a car batt has 6 cells so thats 12-13.2 volts.

given that info, id say your voltage regulator on the alternator is shot.but these days that means you need a whole new alternator, as the VR and the alt are one unit now. and yes as Sam said, I'd replace the batt too as you may have done irreversable damage to the plates in the batt


You'll never touch God's hand
You'll never taste God's breath
Because you'll never see the second coming
Life's too short to be focused on insanity
I've seen the ways of God
I'll take the devil any day
Hail Satan

(slayer, skeleton christ, 2006)

Have you disconneted both cables at the battery, then the earth/ground negative cable from the chassis earth point or points and cleaned the terminals and also the connection area on the chassis.

It could be that your earth connection is bad and the regulator is trying to compensate for the high resistance/ does not seee true battery voltage. This would also account for not being able to jump start it and the starter/lights not operating

Here is a link to Quick Start Automotive Electrics, this is for the CS130 style alternators and you will note the regulator or rotor is only suspect above 16 volts.

http://www.alternatorparts.com/cs130_sbpage3.htm It is a free 6 page repair manual.

I think your alternator and battery are OK and it is a wiring/earthing problem. I would expect that voltage to come down to 14-14.5 volts once the fault is traced

As to the multimeter I have a $5CAD multimeter (Purchased in a sale) which works very well on car,tractor and 220 voltsAC.


Hope this helps


Alont

sounds like you might have a parasitic drain there my friend

something is eating up your juice when ur key is off...

I started the car up fine this morning so that rules out a drain. BTW, I have absolutely no after market parts on the car except the intake which will not draw any power. Is 14.8 really that high? I read in a couple of places that the GM regulators are set at 14.8 so the alternator puts out 14.8 volts while other cars are set at 14.3 http://www.landiss.com/battery.htm . If this is in fact true, it makes total sense cause I tested my dad's corolla and it puts out 14.36 with the car running. I also did a test on the car with all the accessories running, ie. heater, defogger, stereo, dome lights, headlights and tested the voltage again with the car running and it comes out to about 14.5 - 14.6 so the alternator seems to be working fine. Unfortunately I live in canada and cannot bring my car to AutoZone for a free test. I can only bring it to canadian tire which will test the alternator only after you take it out of the car. Unfortunately, I'm no mechanic so cannot do much. I really want to avoid replacing the alternator if possible as the dealer quoted me $450 CAD + tax to get a rebuilt alternator. Should also mention that no lights are going off on the dash. I'm hoping it was just a ground wire that was mis-placed or something.

Alont,

I apologize for being a newb but what is the "earth/ground negative cable from the chassis"?

Thanks,

No Problem

I am sure there is nothing wrong with your alternator-your readings are OK to me I am convinced it is a bad contact, this sometimes happens at the battery terminals but in your case I think it is a contact problem at the chassis. It's no good checking to see if the connection is tight it can quite often be tight but it is not "Shiny clean" . You will have to disconnect the cable, clean cable and contact piont on the chassis and tighten it back up.


First remove BOTH cables from the Battery terminals, it's good practice to always disconnect the Negative-ve(Earth) cable first and connect it last.

The Positive battery cable is from the Battery positive, usually through a Fusible link (This is just a short length of thinner gauge cable that acts just like a fuse) and then on to the Alternator Positive +ve usuallky marked BAT.

The Negative or Earth/Ground cable is the one that you removed from the Negative-ve terminal of the Battery. If you now trace the cable you will see where it is bolted to the CHASSIS. The alternator casing is also bolted to the chassis and this is the return path for the current.

Some Cavaliers have another branch of this same cable bolted under the battery tray so you may have to remove the battery before you get around to cleaning the terminal ends and the points where they contact the chassis.

TIP If you do remove the battery set it down on somewhere smooth with no gravel or stones around. I recall someone removing the battery, sitting it on the ground and then being surprised when the car would not start. A small stone had adhered to the base of the battery and than been punched through the base as the securing clamps were tightened.

I hope this helps and does not confuse

Alont

Load test the battery. Your VR, as myself and mikec said, is prob shot as well.

The grounding is not a problem, as the car starts and stays running. A bad ground would NOT cause a drain on the battery, just doesn't make any sense at all.

Earth ground is a ground to the EARTH, duh, I know. It's like a lighting pole, which is a metal pole taller then a building going into the Earth. When lighting hits the pole, it does no damage since the electricity goes to the ground. Earth ground is NOT found on cars, since they ride on rubber and is isolated and insulated from the Earth.

Alont, I don't mean to be mean or rude or anything, but what are your credentials? Mine are: Auto 1 in HS (I am 19 now), almost MECP certified (going through a program) and I have been employed at Advance Auto Parts for 8 months. Also, 2+ years experience working on cars, 2 of them being my Cavaliers.


Ban low-performance cars, not high-performance ones.

the "grounds" on a car are just to provide a return path for current back to the source (battery). if you really felt like it you could hook all your ground wires back to the battery negative terminal and it would work. thats how they do it on composite frame airplanes that have no metal framework, and aircraft electrical systems are very similar to automotive, just more comples. and FYI I am U.S. Army trained and certified aircraft electrician, and am working towards my FCC licence as well as my A&P aircraft maintenance licence, so i know a little of what im talking about


You'll never touch God's hand
You'll never taste God's breath
Because you'll never see the second coming
Life's too short to be focused on insanity
I've seen the ways of God
I'll take the devil any day
Hail Satan

(slayer, skeleton christ, 2006)

Also, since the VR is prob broken, the battery might be over charging, causing a decrease in electrolytes (spelling?) which would also cause your car not to start.

Sam


Ban low-performance cars, not high-performance ones.

Well I took the car in to get the alternator load tested and the mechanic told me everything looks fine. I mentioned to him that I had a reading of about 14.8 at the battery and he said that wasn't out of the ordinary. He said that was acceptable and that my volt regulator was not shot. He mentioned if it went into the 15s to maybe get the alternator changed. He told me if the VR was shot, the alternator should be pushing more than 14.8 with all the accessories off which is how I tested it. He believes it was just a loose wire somewhere or corrosion. He also tested my old battery which could not even power the dome lights in the car at the time and told me it was fine as well and it had a charge which would support the theory of a wire not being connected somewhere. Well the car seems to be running fine now after the second time I put the new battery in so whatever connection that was loose before is probably fine now. wasted $120 CAD on a new battery but I'm glad I didn't have to shell out another $500 to get the alternator changed.

Thanks for all the help guys,

Great Michael, good to hear it's going and you have reassurance from the tech.

By the way did you ever clean the cable lugs that attach to the battery? It could be where the bad connection was.

This is what I had thought about posting, it's all"Old Hat" now but the links have some interesting reading when you have time

No offence taken Sam

Ok then "Ground " is a term used for the return path as mikec says (Thanks mikec), I just used earth/ground as a general term for return, a bad habit I must have gotten into in my many years with aircraft/motorcycles/tractors/cars etc. It is also a term used by GM and Alldata

The bad ground/return, I agree, will not cause a drain on the battery, quite the opposite, as evidenced by the fact that Michael Lam has a battery reading of 12.86 volts.

It WILL prevent current flow!.

This sounds like a good battery to me, which has not been drained and yet even the dome light will not illuminate.

So there must be a high resistance somewhere in the circuit?.

Listing the sequence of events:-(Correct me if I am wrong, Michael Lam)

1. Attempted start--No ELECTRICAL power, not even the dome light.

2. Jump start with a friend's car-Starts up-go to work

3. Lunchtime- No ELECTRICAL power, --even hooked(jumped) to another car (But battery later tested GOOD)

4.Fit new battery-Starts up

5. Won't start-with NEW battery (Here's the clue0

6. Go to get battery checked--checks OK

7.Battery refitted--All OK. (Now the connections have been remade)

Michael Lam wrote:-

[I read in a couple of places that the GM regulators are set at 14.8 so the alternator puts out 14.8 volts while other cars are set at 14.3]


This IS true Michael Lam, it's why I think you had a bad connection, either at one of the battery terminals or the negative cable was moved enough, when you swapped batteries, to make a good contact. Your charging system is operating as I would expect.

If the battery voltage is 12.86 then the charging system has to be higher to overcome internal resistance and pass a charging current through the plates. GM set theirs at 14.8

Diagram of alternator system, negative RETURN shown in GREEN
http://www.autoshop101.com/trainmodules/alternator/alt128.html

GM Reference to GROUNDS meaning "returns"
http://www.oeplus.com/domestic.html

http://www.forparts.com/str-chg.htm 13-14.8/9volts GM reference

Happy motoring

Alont

Yes that's exactly the order of events. The car is running fine now so I'm going to leave it alone. If it occurs again, I'll clean the wires.

Thanks,

i checked my old alternator 14.7 on the dot, then my new one 14.7 and my friends z24 too 14.7 and doesnt budge even with a load tester on it. my does go up and down a bit, but he he said here in Canada i cant get it checked unless i take it out and bring it in. plus they said it would take awhoile to tested which= downtime plus my labour to remove it.

Hi Nick

Why did you remove the OLD alternator?

I see you have an underdrive pulley, which will drop the RPM of your alternator!

Alont

i think the barerings went on it, it was making alot of noise then the batt light came on. also i changed the battery the same week so it couldnt be the batt. yes it does drop the rpm of the alternator and i bought one from canadian tire and now the voltage is fluxuating up and down a bit when the car returns to idle i can see the lights dim for 10 secs then it will be fine. but dont want to take it out to get it check like i said down time, daily driver.
stock alternator lasted 8 month after i installed the pulley, never have any dimming or any problems. every winter before the pulley it would make a gringing noise like dirt or salt got in there.
i could tell you how to remove it if you want? but borrow a breaker bar for the tensioner.