88Roc350TPI

Ok, here's a stumper for everyone, Yesterday the car stopped charging AGAIN! (4 alternators in the past 2 months) The last alternator was the better ACDelco remanufactured. I take it in and they put it on the tester, it tested OK. Bring it back home checked that everything was indeed hooked up ok, still no charge. So I take it off, go back and get warranty exchange for new one. Bring that home, put it on, NO CHARGE! So, by then it was about 8pm and I'm sick of working on it all day. Go out to my GMC K1500 that I know for sure that the alternator is working on, pull it off, put it on the car, NO CHARGE. The big wire on the back of the alternator that goes to the battery has good continuity so I know that circuit is ok (I think anyway). The question then comes down to the other plug. This is the CS alternator, the plug has 3 wires. A bigger red one (like 12ga), a tan one and a brown one. The red one is 12V hot all the time and the other two appear to be grounds. Is this the way its supposed to be? What can I do to check these and/or where can the wiring problem be thats not letting this alternator energize to be able to charge? Thanks for any ideas.

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Ed Stevens
88Roc350TPI
1988 Camaro IROC-Z
350 TPI
700R4
T-Tops
"1KILLRZ"

Corry

Not exactly sure about the wiring, or the history of your prob (I said in my topic up there I am too lazy to go get my manual) Anyways, have you had your battery checked? A dying/dead battery will kill an alternator or 4 since the alternator is working extra hard to try and charge the thing. It's not too hard to pull it out and have it load tested!
Good luck!
Corry

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Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
1987 Pontiac Trans AM (GTA?) 350 or is it a 305?! TPI
SLP 1 3/4" headers, 3" cat back (stock cat
MSD ignition.
MSD Blaster SS coil.
3.73 Rear end gears
Accell 8.8 Wires
Bosh +4 Spark Plugs (Don't know if they really help but hell!)
Holley AFPR
Race Built Automatic trans ('vette servo, shift kit, tightly packed clutches)--just needs titanium gears now!
Newly gutted cat (the car gutted it's own cat!)
Hypertech Chip (Just found out I had it! :eek
More soon when funds are avail...

Mark A Shields

Check for bad belts, I had purchased a new battery and alternator and as soon as I replaced a belt the car started charging right away. Just something to check.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
UNDERDRIVE PULLEY
ACCEL HEI DISTRIBUTOR
2:73 GEARS

88Roc350TPI

I'm pretty sure that it's not the battery. Battery shows the standard 11-12 volts on the gauge when the key is on but car not running and when the alternator was working the needle was just a hair over the 13 mark. HOWEVER....when the fans are on it rides just below the 13. I'm thinking the combination of 2 fans on and headlights and heater on at night may be contributing to the death of the alternators, but now in light of the present problem I'm beginning to think its a wiring problem. Does anyone know what each of those 3 wires on that plug do/go/etc? Like I said, the red one is +12 volts and the other two appear to be ground. Thanks

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Ed Stevens
88Roc350TPI
1988 Camaro IROC-Z
350 TPI
700R4
T-Tops
"1KILLRZ"

88Roc350TPI

ttt

coach

I would say the battery is the culprit. A battery can read 12 volts and be unhealthy. With the car running and a good alternator, the voltage at the battery should read in the low 14's. Using accessories such as heat/ac,stereo,lights will drop it down a bit. I could understand getting one bad alternator, but you tried several and ended up with the same results. I agree with Corry, get the battery load tested. Also,if you haven't already check your connections for corrossion at the battery terminals.

In your post you said the car stopped charging. Do you mean it died while in transit? If that's what happened, then I would say that it was your alternator.

I had a similar problem with my car. It would charge fine when running (good alternator), but after the car sat for a few hours/overnight I couldn't get her started without getting a boost. It was the battery.

82z

Why the hell would you change the alternator more than twice? You wasted a lot of time and probably pissed off some parts people. Did you do a voltage drop test on the isulated and ground charging system circuits? The problem is most likely your battery. After you remove the surface charge the battery at full charge should read 12.6 volts. 12.4-12.6 is considered 75% charged. Use a dmm and see what the battery reads. If it really is 11-12 volts you need a new battery. Don't trust the dash gauges, thirdgens are not known for super accurate gauge readings. I'm pretty sure the problem is the battery. The wires on the alternator I believe are the amperage output, volts light and voltage regulator sensing wire. Don't quote me on that though.

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82 z28 350cid, vortec heads, comp 262h cam, Holley 600cfm carb, 2in twice pipes, MSD ignition, turbo 350 trans, 3.73 posi, manly b&m megashifter

88Roc350TPI

Ok....I understand all of your concerns with my battery, but here's whats going on....the battery has all kinds of life in it, it cranks the car over great and so on. Typically with the key switch on but the car not running you are going to get around 12 volts which i'm getting, and when you start the car, the wiring that goes into the plug on the top of the alternator energizes the alternator which causes it to make power which comes out the big wire that bolts on the back to charge/maintain the battery. The issue here at this point is that the alternator IS NOT getting energized for whatever reason (therefore the volts don't rise to the nominal 13.9 volts while the car is running). The main question I'm asking is what the wires in the plug are supposed to do? If anyone has a shop manual with a good wiring diagram in it could they look and tell me what each does? There is a brown, tan, and red wire in the plug, the red is postive and at this point the other two appear to be negative (hooking test light to + on the battery and probing those wires lights it up). Is that the way its supposed to be? SOrry for the confusion, I will double check the battery but at this point I am just wondering why the alternator is not energizing (I have tried two alternators that I know for sure are good)

Thanks

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Ed Stevens
88Roc350TPI
1988 Camaro IROC-Z
350 TPI
700R4
T-Tops
"1KILLRZ"

Corry

Yes, but a dying battery will crank! It will just take an enourmous amout of power to charge it, which kills alternators! I had the same thing happen, alternator died. Replaced it, 6 months later the battery died. Totally unexpected ly too! I was refilling the coolant system after changing both radiator hoses. To work the air out, you start the car w/ the radiator cap off. So I did, and it ran for about 6 mins. Shut it off, top off the radiator...do this about a total of 3 times. When I put the radiator cap back on, thurn the key, the lights go out, the fan shuts off, but no start (*note my fan is always on) Try charging the batt, no go. It showed the batt as taking a very small amount of charge, but the charger is ~20 years old so I didn't really trust the guage. Finially at my mechanic friends request to humor him, I went out and got a battery....the thing fired right up, and hasn't had a problem since (well, except for my timing woes post hehe)

Stuart Moss

As you correctly stated, the largest wire, from the factory, is an 8 gauge wire going directly to the battery positive terminal through a fusible link (of course, if the fusible link blew then it'd be "open").

The other two wires connected to the side (not rear) of the CS-130 alternator are to sense voltage and "turn-on" voltage.

The red wire is to sense battery voltage (and hence determine the alternator output voltage). It does this through a wire connected to the starter solenoid at the terminal where the main battery positive cable is connected via a fusible link. The other wire is brown and will have +12VDC when the ignition is "on", zero volts when "off".

The red wire is 12 gauge, the brown wire is 18 gauge.

With the engine "off", remove the alternator connector and see if you see battery voltage on the sense wire. If so, it should be okay. You should not see any voltage on the thinner brown wire until you turn the ignition key to "on".

You thought that they were at ground potential because you tested them with a light (one side to +12, the other to the wire). That should not happen to either. The sense wire should show positive 12VDC all the time. The smaller brown "ignition on" wire should be +12 with the ignition "on" and zero (0) volts with the ignition "off".

All the other posts were correct in their advise. The best way to check the condition of a battery is to measure the specific gravity (you'll need access to the electroylitic fluid). Second is to measure the voltage under load (as posted above). If you can put the battery under a 200 ampere load for five seconds, what is the battery voltage at the end of the five seconds?

If you can't do it either of the ways mentioned above, from a fully charged battery, drain it a little by giving it a good load for 10-15 minutes (headlights on, fan on "high", etc.), then try starting the car with the ignition coil disabled (to prevent the car from starting) so you can crank it for several seconds. It would be good to know the battery voltage when starting. If you don't know, does it turn over normally or slow? A lot slower? Will it maintain the same cranking speed for the 5-10 seconds you crank it? If so, then I'd think the battery is good.

The above post was right on when he stated that replacing alternators could be due to a battery (remember even though it starts fine, its capacity, or ability to provide current for its rated period, would not normally be known). CS-130 alternators are known to have a problem overheating when providing a lot of current for a long time (I'd guess >60 amperes >20 minutes). A bad battery could cause an alternator to provide a lot of current for a long time, which would then get hot (and usually destroy the rectifier).

This is why normal CS-130 alternators should not be used to charge a dead battery for more than ~15 minutes at a time (before allowing it to cool).

This is also why it is important to know the continuous hot power output of an alternator when selecting one. Some manufactures boast high outputs (especially >150 amperes), but is not too meaningful if you do not know if the rating is for continuous duty and HOT. (A colder alternator will produce more curent than a hot one.)

bottledpower

according to the prints i have, you should have a tan (or brown/white) wire which is a 100 ohm resistance wire. this wire is hot in run and energizes the field in your alternator. the other brown wire will go to the voltmeter. turn the ignition on and check for 12 volts at the brown wire, and yes they go bad. ive rewired mine before.

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85 IROC 350 11:1keith blacks,.555lift erson roller cam,1.5 crane roller rockers,edelbrock intake,holley 4150 750dbl pumper, nitrous oxide,full length heddman headers,true dual exhaust, 11"stall converter, 700R4, 3.73 locker

Greg

make sure the ground wire that connects the body to the engine is good. It is located above the passanger side head and bolts from the body to the cylinder head. This will cause it to not be able to charge over 13 volts.

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'89 Formula 383 TPI

Demon Z28

heres some pretty basic and stupid questions/suggestions ... but in the long run they turned out to be why mine wasn't firing before...

You said it turns over, but I'm guessing it doesn't fire... means your battery and alternator are fine ...

Do you have spark?
Have you checked your distributor (Rotor, Cap, Coil, Module?)
Check your plugs?
Have you checked the water in your battery caps? (this one is a big one, it makes all the difference sometimes)

How much have you searched for other problems before accusing battery, alternator, or wiring?

Mine would turn over countless times... but I wasn't getting any or enough spark... at first I thought it was battery, alternator or wiring... then I looked into it a bit more and figured if its just turning over, those must be fine, time to check something else...

I bought a pertronix distributor rebuild kit.. Coil, Cap, Module, Rotor, weights, etc...

Fixed my problem pretty damn quick

Check your distributor, may be time for an upgrade

Sure is cheaper than an alternator, battery and wiring hehe

Don't replace something thats perfectly fine, some people will read way too much into a small problem without checking rest of the possibilities first

Superblue87Formula

the previous two posts are dead on. According to my diagrams, all 3 of the terminals should have positive voltage when the car is "on" the first terminal recieves power via a 100 ohm resistor on your gauge panel circuit. The middle one is jumped off the first one (in my diagram) the third voltage sense is wired to the battery positive terminal. The power on the first terminal excites the stator so that the alternator will charge, w/out it you will have the problem exactly as you described (I know because my firebird ended up with it 2 weeks after I bought it) you can jump another hot in run circuit into this one to power it, don't use an always on circuit or it will slowly drain your battery.

Demon Z28

I hope my post in this doesn't go unnoticed Don't wanna see it burried by technical alternator mumbojumbo hehehe

88Roc350TPI

PROBLEM SOLVED!!

Thanks everyone for writing. First, I'm going to warn Corry about even getting near that radiator as the car approaches temperature, thats what caused this whole problem I had. I went to a friends house, noticed that the volt gauge was low. We had just replaced the radiator a couple hours before at my place. Well, I decided to check the water level when I was under there to see what was going on with the charging. BAD MISTAKE!! Turned the cap to the first notch to let off pressure. Then after a minute or so took it off. At that point water shot 40+ feet in the air, covering me, giving me the equivelent of a nice toasty sunburn to my face, chest, and left hand (AND I HAD A GLOVE ON!!) So I got to spend a couple hours in the emergency room. So, here's the verdict....When installing the new radiator, the tranny cooler line got lodged against the fan. I have one fan wired to ignition on right now (tan wire on the fan relay to the black wire that goes to the fan) and the extreme load on the fan blew the FAN fuse in the fuse block. WELL....Some brilliant GM engineer decided that they would use the same circuit for the energize wire on the alternator. Soo, new fuse, and got the tranny wire out of the way and it charges fine, the alternator wasn't bad at all. The first 3 that blew out on me were though. They were Advance Auto Remans which I don't have faith in anyway. The present alternator is an AC Delco Reman. I think that one of my fan motors is getting bad and drawing excessive current as well, so nighttime driving with fans on, headlights, heater, fog lights, etc was killing the alternators. We put load test on the battery and it showed good. I think I may get a bigger battery with more reserve anyway just for extra insurance. A person I know went thru 42 alternators in his IROC and switched to a dual battery setup and hasn't fried once since. So that theory is a good one. Thanks again everyone for your help.

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Ed Stevens
88Roc350TPI
1988 Camaro IROC-Z
350 TPI
700R4
T-Tops
"1KILLRZ"