trukn1

ok,, am having a REALLY annoying problem and I believe I have thrown just about every part in the world at this one. I know that throwing parts doesn;t always solve a problem but in my case it helped me discover a few i didn;t even know I had; so was a good thing. Need some help, which may just reinforce my next guess.

Victim: 92LS
Problem: Battery drain,, will not charge battery
Solutions:
a. Alternator has been replaced along with new serpentine belt (was old)

b. Brand spanking new battery installed on Sat. (replaced one that was defective and under warranty)

c. 120amp alternator has been replaced with new (old was corroded and really needed to be replaced.

d. wiring harness plug (on top of alternator) has been replaced. Old one had a wire break off in the harness. Took one from a donor, spliced and gave myself some extra length so I don't put a strain on that wire combo when I have to replace alt.

e. Even went so far as to remove the capicator I had in the trunk for the stereo thinking that it had somehow gone up and was draing the system faster than the battery could recharge it.

My problem is, on a fully charged battery, the car will run fine. Even when I take a volt meter and put it on the car, it will kick out to the normal levels. Removed the positive battery cable while car was running and car stayed running (old school test for bad alt). Volt meter indicated that system was working as it should. After driving the car, with newly installed battery, Saturday night I got about a mile from my house and the Gremlins came back. The following lights came on the dash:

Battery, e-brake indicator, oil light, and antifreeze light.

Instantly turned the car around and went back home b4 she died completely as my headlights got VERY dim quickly.

Someone please let me know what is going on here. Each time I have done some sort of repair, car would run fine for a few months and then the problem would come back. My car is not run but on the weekends /c of my job. My last resort is gonna be checking all of the grounds to make sure that one of them has not come loose. If someone could send me a diagram of where the grounds are, it would be very appreciated.

This problem has been plaging me for the better part of this year and needs to go away. Elsewise the entire car WILL go away as I am almost to the point of giving up. Any help you guys can render woudl be appreciated.

PureDrifter

iTrader: (10)

sounds like you have bad wiring or some other electric draw somewhere.

this is going to suck for you, finding stuff like this (breaks/errant draw) is always a real pain.

python

iTrader: (4)

first of all....DONT EVER DISCONNECT ANY ELECTRICAL WHILE ITS RUNNING! you can disconnect a battery on a 65 mustang while its running but dont do it on ur car. now u need to do a parasitic drain test
http://www.ehow.com/how_2249402_find...ery-drain.html

billydpowe

iTrader: (1)

YEP, you have a hot wire somewhere, that grounds out and drains your battery, so the above test might not find it, if it is not grounding out when you do your checking. there is no easy answer, for you or a professional, but do all the testing with out buying other parts until necessaary. needless to say, this is not common on any car.

3UZFTE

Can you explain to me why not? People have been doing this for years, there's nothing wrong with pulling the battery from an idling car. The link is a good one, but may not help you find all of your drain, as that will help you find a drain when the car is shut off, not while it's running, which it may or may not be. Although your first attempts to try to fix it were pretty good, alternator not keeping charge, and than a battery not holding it. However, it hasn't fixed your problem, I don't think any of those parts are your main focus, they may have failed in the process, but there's obviously a deeper issue.

1. You said the alternator reads normal levels, what exactly is the output of the alternator when the vehicle is running?

2. Check your battery cables, make sure you have good grounds, no corrosion, and good connections from battery to ground, battery to alternator, and any other connections in that area that might see corrosion.

3. It's not likely, but it's possible that you may have a faulty replacement part.

4. Start ripping into the wiring harness to look for chafing, rubbing, burned, or cut wires through the harness.

PureDrifter

iTrader: (10)

most likely because on ECM controlled cars the power surges from the alternator without the battery to act as a buffer will not be kind to the ECU and related electronics.

Rising_Sun

iTrader: (2)

I've had this problem many times. But as I speak to more LEXUS/Toyota owners, this is a common problem. Check your Negative battery terminal and if you don't drive the car regularly then consider getting a battery tender. Harbour freight have solar tenders cheap.

trukn1

Pure- You're just full of good news, huh. LOL. I pretty much thought the same, just REALLY didnt want to stat hacking into the harness for visual checks. May have to wind up doing so anyway.

Billy- The parts I replaced were mainly under warranty anyway, so needless to say, I hav PO'ed a few store personnel returning warranty parts. The parts I addressed and replaced needed to be done anyway, and in the process of eliminating the problem I went ahead and did so since I was already there anyways.

3UZ-
1. Alternator output reads around 14 @ the battery and cable from the alt. to battery @ idle. Battery is reading between high 12's to 14. Battery will drop down to 12 under full load and start to charge back up under acceleration. I had a friend of mine take a voltmeter to measure the output while I put the car in drive, holding the brake, and turned everything on. Voltage never dropped below 12 under full load. Am quoting numbers from memory so I dont have the exact ones now. I only get to work on my car on weekends when I am home.

2. connections are pretty much on point, since I have chasing this problem for several months now. My car pretty much sits all the time since I drive cross country for my job (trucker) battery is unhooked when I am away. No corrosion that I can see and I know the connections are on point, since I hook them up when I come home to drive the car.

3. I thought about the faulty replacement part theory, but honestly in the past year I have replaced the alternator 4-5 times. Yeah, they did wind up being faulty but some it probably was b/cthe problem that I am STILL hunting for to resolve did not go away, but was held at bay. I have had my alternator bench tested, results came back good. I have JUST (as in this past friday) replaced a defective battery(under warranty) and I know this is good. The drain comes so bad and so fast that I have pretty much drained an Optima yellow top battery, several times, and this battery has been with me over 3 years now. Yes this battery is still good. Had it benched as well. I have also had the car scan tested at Autozone, where they put on the computer and run all kinds of drain tests. Results would always come back good, and approx 2 hours later,,problem.

4. Wiring harness is about the only area that I have left to check. pretty much eliminated everything else, and this is a real pain. This problem needs to get right or sadly,,she WILL become someone else's problem(with full disclosure of course).

Rising sun- Am gonna start here first, by completely replacing the negative battery cable period. Is easier than ripping into the harness. Battery tender is not needed when I am away,, got into the habit of just completely unhooking the battery.

ssdoeg2

I had a similar problem with the battery drain on my recently sold 91LS. I replaced the negative battery cable and the problem cleared. If the connections aren't real solid then at times the car will charge fine and at other times the battery won't get charged by the Alt. due to faulty connection and the battery will drain down (fairly quickly at night with your lights on).

trukn1

That seems to be the concensus here, so before I tear into the wiring harness looking for a problem that may not exist there,, am gonna replace the negative cable first to see if this clears the problem. Can't do that until I return home this weekend.

JimsGX

Trukn1,

Check out this thread in the LS430 forum, post #9 may help with some diagnostics, even though it pertains to an 02 LS430...

https://www.clublexus.com/forums/ls4...ests-fine.html

randal

That would seem to be a problem right there. The alternator *should* easily be able to keep the charging voltage well north of 12 v (>13v actually) at idle with full load.

If it were mine, I would check the charge voltage at idle with everything on (lights, rear defroster, seats, brakes) and note the exact voltage. Then, under the same conditions, slide over to the output terminal of the alternator. You will see some difference but should not be more than a few tenths of a volt. If more than that, you have a harness/connection problem(too much IR drop). If not, you have an alternator problem.

trukn1

It may very well have been above 13. I was citing numbers from memory, as I was not in front of the car at the moment. I drive cross country for a living all week, so needless to say that there are numbers in my head all the time. Will be going home to double check the numbers again to see what turns up.
and see what the output is. Still gonna change the negative terminal since it is cheap to do so and it will give me piece of mind, and yet another elimination item to check off before ripping nto the wiring harness to start loking stuff over

trukn1

Well,, stayed out in the cold yesterday and did a few things.

1. Re-grounded the main battery ground wire with a new replacement and found a fresh gound point to do so.

2. Replaced the negative battery terminal with a new terminal connector.

3. Took a voltmeter and attatched to get some numbers.

here is what I have found so far,,haven't ripped into the wiring harness for visual check,,yet.

My negative battery terminal was replaced a few years ago when I have my subs instaled in the trunk. Part of the wire was left exposed and just taped over and it looks like some water had gotten to the ground wire itself and corroded; hence my decision to just replace the entire cable itself. I replace my negative terminal connector with a terminal connector which had 4 outlets to ground (helps when I add some more audio and need to have a good ground point. Relatively easy wire cleanup.). I also found a new, fresh ground point in order to use as opposed to the previous one (on driver side fender by fuse box). After doing so I hooked up a voltmeter to get some readings to see what was going on. My battery charger has a deep cell cycle (I have an optima yellow top), as well as a setting where I can read the output of the alternator, and hotshot the car. Here is what I got.

a. Car @ idle 13.8 at the with heat on ful blast,,drops down to about 13 with radio
and subs.

b. car under load (headlights, Heat on full blast, Radio with Bass turned all the
way up) @ idle would drop down to 12.5 with these things on. give it gas would
shoot back to 13.8 with hesitation.

c. Alternator output remains at a constant 14 volts on the wire coming directly from
alternator to the positive side of the battery. Alternator itself had been previously
tested @ autozone on the computer and it passed the tests. Wire connection
(harness) is in good shape,,wires are good,,this was replaced by me a few months
back on a previous repair attempt. Battery is brand new.

Buddy of mine took the car with him after repairs were done, drove it around town, and reported that he could not get the warning lights to pop on and that it did not act up all night (we traded cars for the evening). I retrieved my car this evening, finally convinced that the problem had been solved and low and behold after 10 minutes of driving,, the gremlins appeared again. I had the headlights, heat and radio on since it was nightime and cold out. Once again the Battery, e-brake, low coolant and low oil lights(yellow indicators at the bottom of the cluster) came on and stayed on. Pissed as this, once again, I decided to keep driving home since I had an extra battery with me just in case I needed to do a quick change in order to get home. The distance from my moms house to my apt is all the way across town( approx a 35 minute ride). I rode home the entire distance with the warning lights on as well as the headlights, heat and radio as I knew that if I had a true drain problem then the car would be running solely off of battery alone and would not last more than 15 minutes(tested this theory before,,dies in 15 minutes on battery alone). I made it all the way home and noticed that as I way driving, thru the city in traffic, I would look at my headlight brightness in the reflection of the cars ahead of me. They were not dimmed at all,, and a true drain should have dimmed them considerably the longer I drove. This is sadly leading me to 1 of 2 things left to consider,,

1. As some of you suggested,, a break somewhere in the wiring.
2. This one may make more sense to me, in hindsight, a possible appearance by the
infamous bad circuit board that our first gens are famous for. In hindsight, my
cluster would flick from time to time(never thought anything of it since it was far
and few between in it's happenings. I do remember even seeing a very small puff of
white smoke which came from the panel area. I did not think of it b/c it was cold
and you could see your breath, we have had some cold weather here in Md lately.
Sadly I am thinking I may have a wacky intraument cluster and will have to look into repair. Will keep advised,, this is what I have found so far.

PureDrifter

iTrader: (10)

while you were at it you may want to pick up one of lextreme's alternator cables, beefy stuff.