Does Anyone Know Anything About The Electrical Wiring In Our Cars? Heres My Dilema....i Just Had A Brand New Alternator Put Into My Gs300 The Day Before Yesterday. Yesterday When I Got To The Office The Battery Light Was On? After Work I Got Into The Car And It Wouldnt Start? I Jumped Off The Car And Just Barely Made It To The Mechanic. I Have A Yellow Top Optima Battery In The Car. The Mechanic Replaced The Alternator With A Brand New One But I Still Have The Same Problem...he Said It Has Something To Do With The Electrical Wiring? Now I Installed My Own Stereo System But I Know I Have Done That Right...i Have Been Installing Car Audio For 6 Yrs Now. Does Anyone Know Where I Might Begin To Look For My Problem? My Car Has Done This To Me Before, However, It Just Seemed To Fix The Charging Problem By Itself? Does Anyone Have Any Suggestions...i Just Want To Fix It And Be Done With It? Someone Suggested That I Put My Optima Battery In The Trunk And Run The Car Off A Regular Battery? Any Suggestions Would Be Greatly Appreciated.
Thanks Everyone That Reads This!

 

Put a voltmeter on the battery make sure you have 13.9 to 14 volts at idle or 1000 RPM. Check voltage with engine off should be 12 volts minimum. Do you have an underdrive pulley, if so that's your problem. The car probably won't charge till it hits 3 or 4 thousand RPM'S and it will not be enough. Been there and solved that problem.

 

Thanks For The Feedback! I Dont Have An Underdrive Pulley But I Was Looking To Get One....not Any More!? I Just Picked Up My Car From The Mechanic And Not Even A Mile Down The Road The Battery Light Came On? When The Car Was Running The Voltage Meter On The Alternator Was Reading About 14.44 Volts. I Dont Know What To Do? I Just Called A Specialty Shop That Deals With Electrical Problems And They Said Bring It In On Monday But I Really Wish I Could Solve The Problem Myself? I Started Thinking That It Might Be The Body Ground Or Maybe One Of The Cables That Carry The Vehicle Eletrical Current To Battery Or Alternator? Then I Start Thinking That There Is A Short Somewhere? What Corrected Your Problem?

 

Ok 14.4 is good! Where are you measuring the voltage at? What are you using to measure it with? Are the battery terminals loose? Is the battery light coming on even when the alternator is reading 14.4 volts?

 

I Was Touching The Positive Terminal Of The Volt Meter To The Alternator And Grounding The Other Terminal. I Believe That The Battery Light Is Still On When The Alternator Is Reading 14.4!? When You Say Are The Battery Terminals Loose...they Dont Move When I Try To Move Them..so I Would Say No They Are Not Loose. Do You Think I Should Buy New Battery Cables And Terminals And See If That Makes A Difference? I Really Appreciate You Taking The Time To Help Me Out!?

 

Does it read the same thing at the battery?, how about with the engine off? No, on the battery terminals for now, unless they are full of corrosion. It's possible your optima is going bad and not holding a charge.

 

I Just Bought That Battery Brand New About 6 Months Ago!? Autozone Should Give Me A Brand New Dont You Think?

 

Yep, If it's bad you'll get a new one. Something else to think bout as well, the stock alternator is 80 amps, it looses about %20 efficiency once the case gots hot. That leaves you with about 64 amps to run the car and your stereo. If you have a large stereo and you play it loud most of the time you're driving the alternator most likely won't be able to keep up. So all the extra juice comes from the battery. Well when the battery is too low and the alternator can't keep up, it causes problems. Such as the battery going dead very quickly or not starting the car. You really should install a voltmeter inside the car where you can view it while driving or playing the stereo.

 

Turbogs300 brought up a good point. I would have the alternator checked. Have all the lights, including fog and highbeams, a/c, heater, cd player, defrosters, wipers, all electrical accessories turned on, then test how many amps your getting from the alternator. If all this is taking all that your alternator can handle then you won't have enough to charge the battery.
You should also make absolutely sure that all connections are clean and tight. Check the small wire feeding the fuse/relay box under the hood. I'm not sure if its coming directly from the alternator or the battery, but if that is loose or corroded, it can cause problems.
Lastly, on the first gen GS's also on the SC300's (Shares the same engine and electrical layout)
there was a problem with some of the negative battery cables. Something about the way the ends were soldered to the wire at the factory. Same symptoms your having. Your big stereo system might have aggravated this condition. Changed the cables and the problems went away. Hopefully, this can help point you in the right direction. Good luck.
Will

 

Hello,
Sorry to hear that you are having problems! The alternator and battery have a symbiotic relationship. Very often one will fail and take the other with it, or one will fail, and the other will fail very shortly afterwards. It is important when replacing an alternator to test the battery and make sure it has a full charge before the car is started. Alternators are NOT designed to charge a battery fully from dead! Optima batteries are also notorious for needing a big "kick" to get them charging. A really dead Optima will sit on the charger for an hour or more, hardly taking any charge at all, looking like it is fully charged. Then it will ramp up the amps, and pretty soon you are charging at 30amps! If you have a local Inetrstate Batteries distributor near you, take your Optima to them for testing. Autozone might not catch a problem with it....
Do you have an Ameter? (multimeter that measures current) If so, you should check to see if there is any current drain on the battery even when the car is off. A current drain can kill a battery pretty quickly. Be carefull when hooking up an ammeter to the battery, most small meters have a 10A fuse in them and you can blow it if you open the door and let the dome lamp on, etc. Turn the meter to the highest amp setting for starters, and disconnect the positive battery terminal. Connect the black test lead to the + terminal, and the red test lead to the battery cable. You may see 0 on the meter, turn the setting down a notch.... do this untill you see some type of reading. The clock and ECM alway take a little power, but it is a few mA (milliamps) Any sizeable reading is a sign that you have a drain.

Another Ghetto way to see if you have a drain is to gently touch the + battery cable to the battery terminal, watching for a small spark as you connect it. One small spark the first time is OK, as you are charging a few small capacitors inside the clock, ECM, airbag module etc. If you get a small spark everytime, you have a current drain. P.S. try the current drain test with the Ameter both on the car and on the stereo main wire. You may have an amp or component that has gone bad in your stereo and is pulling current.

Please let us know what you find!
Carl Crawford
www.speed-source.net

 

Hey Guys
Thanks For The Feedback! Just An Update I Had My Car Towed To A Shop Called "auto Electric Systems Or Aes" And They Are Supposed To Let Me Know Something Today. They Specialize In Electrical Problems In All Vehicles. They Also Want To Pump Up My Alternator To 190 Amps...im Not Sure About That As Of Yet. I Will Keep You Guys Updated And Thanks Again.

Lexurious1

 

Whats Up Everyone! I Got My Car Back Yesterday And The Electrical System Is Great. The Voltage Regulator Inside The Japanese Made Alternator Was Not Fluctuating Enough For The Power That Is Running Through My Car. The Shop Custom Built A 200 Amp Gm Alternator. They Said The Gm Voltage Regulator Is Alot More Sturdy. Okay My Electrical System Consists Of The Optima Yellow Top Underneath The Hood, Another Yellow Top In The Trunk, And An Isolator. The Isolator Is Connected To The 200 Amp Alternator And Tells The System When To Send Power To The Battery In The Trunk. The Optima Under The Hood Runs All The Car Accessories Such As Lights, A/c, Etc. The Battery In The Trunk Is Soley For My Stereo System. The Whole Process Cost Me 1400 And About 10 Days In The Shop. If Anyone In The Dallas Area Needs This Done To Their Car Let Me Know. I Think Maybe We Could Talk To These People And They Would Probably Give Club Lexus A Car Club Discount. Anyhow Thanks Everyone For The Feedback!
Lex1

 

Good to hear everything's fixed, however you paid way too much. The GM 200amp alt's are the cheapest alternators(pricewise) out there. You could have gotten a denso 200amp for around $500 or a 180amp for around $250, removed the denso regulator and installed an adjustable ford external reg for about $60 or $70 more. Oh, and it would have only taken 1 day at the most. How many gallons of vaseline did you get with that? You should have asked.

 

I Am Curious What Shop Did You Go To In Dallas? JP IMPORTZ Is A Sponsor On Here And He Could Have Given You A Good Price On His Alt That He Sells For Lexus Vehicles Plus He Works Exclusively On Lexus And Toyota.

Just FYI Because I Have Been There A Lot With My '93.

Your Must Put A Lot Of Stress On Your Shift Key Typing Like This. lol

 

I've searched and can't find the procedure on how to replace the alternator.

If anyone knows the procedure or has a link, please let me know ASAP!! Thanks

Max