Gate

I bought my 92 SC400 one month ago and changed the oil on the first day. I check all the fluids for level and condition regularly (every day average, every three days at maximum interval). A week ago it started having problems but for the first three weeks it ran perfectly. The problem started with the battery light. It came on one day and then the engine shut off while idling at a stoplight (I tried a jump, but it wouldn't hold a charge, the engine started and ran beautifully while hooked to the other car, but shut off immediately when the cables were disconnected). I had it towed home and foolishly bought a new battery without diagnosing the problem. It ran fine with the new battery for about 50 miles but then the same thing happened. I thought it was the alternator so I took it out, cleaned it (as well as the connections) had it tested at Autozone (it tested "good"), put it back in, then charged the new battery. I thought that maybe cleaning the alternator got it working again, and that maybe cleaning the connections and roughly checking for frayed wires would help. It ran fine for a day, so I figured the issue was solved and blew my last $25 on some new plugs. Put 'em in, then the misfiring stopped, so that's one good thing. It wasn't very related to the main problem though because the engine shut off again. So I had it towed again, charged the battery this morning, and am currently not planning on even taking it for a test run up the driveway until I've saved up enough for a mobile mechanic to do a true diagnosis to finally settle this. Since it starts and runs fine as long as it has a good power source (booster pack, other car), the battery is new and holds a good charge, and the alternator tested as "good", I think it might be a parasitic drain due to some frayed/loose/"bad" wires. All the fuses are good. But I really can't do much more on my own and I need a real pro to come over. Until then, any input from my fellow Lexus-preferred-car-enthusiasts is exceedingly appreciated.

BigBang

iTrader: (1)

If it's not the alternator it might be the terminals and it would probably something electrical. You didn't recently install an aftermarket headunit did you?

Gate

No, I didn't install a new head unit. The original stock radio remains untouched. An employee at Autozone told me that an amp could causing a power drain, but I told him I don't have an amp in my car. That led me to believe that several other units could be draining it. The stock radio might be, but a radio doesn't use very much power (I don't think so anyways). It shuts off and wont respond about 30 seconds before the car starts stuttering to a shut down, one of signs letting me know to hurry and find a place to park. The A/C display refuses to turn off it's back light when it's about to die too. I actually just replaced the terminals along with that new battery. Maybe they were wrong about my alternator being "good"? They seemed pretty sure at the time, I asked twice because I was so surprised.

OG Dada

iTrader: (10)

Well, hold on, so the engine shuts off after some time since you started it? It doesn't have anything to do with the electrical then, because once you've started the car it's no longer relying on the battery to run it, unless a number of spark plug wires are not working, or the distributor or the igniter/coil. But if those are functioning properly I'd check on the fuel lines, fuel injector or anything that has something to do with fuel and also the throttle, it's a possibility that it's drowning from too much air or too much fuel. What's the background of this car anyways? Was it dealership maintained or like mine repo maintained for 2 years before I got it, or previous owner had fun with it? Those info might be able to help you as well so you can find out what was changed and how it was treated...

Gate

Kingphilip, the engine does run for a while. I don't know how much juice it has left right now (how quickly it's draining, or if it even is at all), but I finally reconsidered taking it up and down the driveway a few times. It performed that well. It's interesting that you mentioned the wires, it failed a smog the day after I bought it (it now has a temp tag, I know it's foolish to buy a car with an undetermined smog status but I bought it from a friend's mom who is very cooperative with my payments and the information she shares) and the man who performed the test recommended to start my journey of emission repairs with a new wire set. Perhaps I'll test the wires with a water spray bottle. I hope that method actually works. I don't know anything about the distributor, igniter, or coil, but I'll research those parts. Not sure how to troubleshoot fuel or throttle issues on my own. As far as air goes, I had to remove part of the air intake system to get to the spark plugs yesterday and a small tear on the end on the rubber boot. It was so small and close to the edge that the circle clamp covered it up, but maybe there are worse damages elsewhere on in the air system. I believe I'm the third owner, the first owner was a Japanese man (I could tell by his last name, he left his repair records and several other paper items in the manual case, not sure ho long he owned it, seemed like a few years worth of repairs) and my friend's mom (Michelle) owned it before me, she had it for three months. She buys cars at auctions and re-sells them, that's where she got this one. Someone apparently had some money to throw down on up keep because Michelle did not alter the car or buy the custom rims - stock rims for this car are 16", when she bought the car it came with custom 18" German Azev type B rims, very expensive, they are the old type B, discontinued, good condition but a custom paint job on them is very worn and they're scratched, the first owner probably put them on. That's mostly what I know about the history. What do you think about temporarily removing fuses for unnecessary components like the A/C and radio in an attempt to deactivate a possible drain in the meantime before I get a chance to actually fix it?

O. L. T.

iTrader: (17)

Replace the ALT, the Armature is shorting. Bare spot in it somewhere randomly making connection. Auto part stores only test the diode to see if it is working and putting voltage out, has nothing to do with a physical test of the ALT condition or armature.

Gate

O.L.T. that is extremely helpful, I wish so dearly that I didn't shell out for those plugs, my old ones might have had a bit more life and that money could have gone to an alternator! I sincerely believe your conclusion but everyone else has been great too. Looks like it's time to start re-saving for an alternator. Do you or anyone else have an opinion on refurbished v.s. new alternator for Lexus?