Hey everyone... This is the situation I'm having. I have a 2001 Es300 Coach edition... My baby... Just had rack and pinion repaired. Suddenly battery started dying after sitting couple of days. I would let idle to try and charge battery after a jump and car would start right up but after a few stops around town wanted to die again. So I figured weak battery had it changed for new. Took her out for spin couple days later had car idling while I ran in store and when I came out she was overheated pass Hot with Alternator light blinking. Pulled over and had towed to the house. OK... Changed radiator... thermostat... And coolant temp sensor with new hose. No longer overheating but...Mechanic was saying Alt... Not running correctly. Took to Autozone it passed. Anyway I just put new Alternator on today and car rpm is a little higher than normal at about 1 1/2... Excuse my non-technical speaking. And it is hesitating like it wants to cut off like a hiccup. Worse in reverse kinda up and down rev. The Alt. light is just staying on... Sorry for long post but does anyone have an idea of what could be going on... She ran like a beauty before. What could have cause her to overheat all of a sudden and quickly. I have look everywhere for info but nothing matching my problem. Please help... Fusible link... Alt. To Battery cable... Ground wire... Is the starter involved? Also changed the 100amp fuse already. Any ideas would be appreciated

 

if the alternator light is on, then the alternator is almost always not charging.

The alternator provides quite a bit of resistance when charging. That explains why the rpm (at idle?) is high, because without that resistance it would free spin higher, it's like having the a/c on, racers often have a switch to turn it off ..

so, my guess is you have an electrical issue, which has caused the alternator to stop being turned on by the car. (queue bad joke), .. I doubt the new alternator is being turned on by the car, check the alternator fuse, there are usually two 10amp fuses, or one 10amp (constant), one 7.5amp (turns it on).

I'd guess that the low power caused the fans to either spin slow or not at all, which caused the overheating, and probably other issues associated with that, overheating even once, to that level is bad, very bad.

 

Check your belts make sure they're not worn. Wouldn't hurt to check the terminals and the cables are secure. I took out my whole battery and cleaned everything today.

 

Thanx JDM I actually have some new battery connections... So I'm going to change those out too to see if that helps. I'll post back

 

Thanks for quick response ES. I'm going to check those 10amps and that 7.5 today. Didn't know that turn it on. I'll post back with my findings. You hit everything on the nose. ( the joke wasn't that bad) Very clear on helping me understand. I have the Coach edition and has been best car ever. It kills me too see her down. Would love to get it up and running before having to hand her over to someone else to fix. I'm a protected owner lol. Ill post soon.

 

Alternators have four wires generally,

A huge one, the output,
a charge light (negative), for the light on the dash, which is on, when the alternator is off, OR when it's 'half charging, which is a technical term for a current output less than 13.8 volts. Its a common misconception that cars run on 12, or 24 volts, they actually run on between 12.5, and 13.8 volts.
a winding exciter, which assists in power generation (constant supply),
a on/off supply, which turns the regulator on, it comes on when the ignition is turned to the second position (run).

very boring, but basically, if the alternator is off, it won't charge the battery and all manner of things shut down, and weird stuff happens. If your car at idle has less than 12.5 volts at the battery terminals, then the alternator isn't running (or is half charging), get a volt meter, test it, see what you find. Sometimes, it's good to test the battery (voltage) with the car off, then again when it's running. and see what you find.

Typically a half charing car will put out about 10-11 volts at idle, and the battery slowly dies because of that. A non charging car will run for around 15 minutes, perhaps 20. A half charging car will run for several days but be hard to start, or refuse to start without a jump. A non charging car will often read something like 10 volts or 9 volts when not running. anything under 10 volts and the car's ecu will not turn on, because it simply can't.


good luck

 

Mine started playing up today too! Probably on my part though lol, don't think that the cables are making good contact. When I put it in drive the battery light comes on.

 

under load, .. you'd think that would be the belt slipping, but I guess you'd hear that.

 

Hey ... Any ideas on what could be if Alt. Is only half charging? Doing those fuses now

 

if the alternator is half/part charging is usually .. for want of a better term ****ed. (faulty regulator), irrespective of whether it is new or not.

 

I think a wire was not put back on--maybe a ground. do a voltage drop test on the grounds. with car on, measure voltage from pos. to ground on motor. then hook up a jumper cable from ground to the neg. post on batt. now meds. voltage again---if it goes up by more than 0.2 V. then the grounds are bad or missing. perhaps a wire to the starter got moved good luck