YACT: Battery Light on car revs high and die without warning?

[djheater]

Ok, I don't know anything about cars. Please help if you can.

Yesterday the battery light came on, on my wife's car a 1998 Dodge neon (stock, manual). It was not exhibiting any other symptom so I was waiting till this weekend to bring it in. This morning she says it would rev real high when she put it in neutral (shifting gears or parking)., then while she was driving slowly down the street it died without warning.

I just had the alternator and battery replaced last October, so I thought it might be a loose post or something, I went to check the car out where it had died and when I opened the door the dome light came on. I got in and started the car, no problem battery light still on. I checked the Battery cables, both were very secure and the ground is intact. I drove it home without incident and when I put it in the driveway and put it in neutral I had the same high revving experience.

I'm taking it to a mechanic tomorrow morning unless you guys come up with something, I sure hope it starts, it's freezing and I don't want to have to pay for a tow truck.

Thanks for reading!

 

[MikeMike]

random guess here but.

for some reason, when your car revs high, it overrevs the alt (i can do it by spinning my tires and revs go up to like 5-6k) and my batt light goes on.

idler belt maybe, or your idle set scerw i dont know.

MIKE

 

[Spikesoldier]

ill take a st@b at it, loose alternator belt.

 

[Quixfire]

Without looking at the car my guess would be the alternator isn't charging the system correctly. The high idle could be caused by a lack of voltage to the PCM making it act up or even not allowing some control outputs to operate properly.

Most idle control devises use a 12v power supply to control the idle, if your system drops below 12v then it wouldn't work correctly and your idle could be higher than normal.

 

[Thegonagle]

Your "mechanic" put a cheap crappy rebuilt alternator in last fall and it has failed.

I guarantee that it won't start and won't run unless you charge your battery.

The car did not "die without warning." The light came on, warning you that the battery was not being charged, and the car would cease operation as soon as the reserve charge in the battery was depleated, which it did. (Read your owner's manual.)

The high idle is probably a symptom that the computer and related systems had no ability to properly monitor and control the engine due to low voltage.

EDIT: If it's not the alternator itself, then it's the belt. Also, the alternator should be under some kind of warranty (unless it's one of those terribly cheap "white box" generic parts), so you should not need to pay for the part. Whether the mechanic warrants his labor is up to him, but a good one will (he should, as he pays a price for his choice to put an unreliable part in, and his reputation is at stake if he doesn't make it 100% right).

 

[MikeMike]

thegonagle, that would be the case, if his voltages, when driving, were < 14 volts but im not sure wether or not he has a volt meter on the dash.

also, you cant drive very far on a gone alt (trust me i got REALLY LUCKY and was 5 min from my house, and turned off my system)

and when the alt goes, you get a noticeable dim in light output.

MIKE

 

[Scarpozzi]

I have a 1999 Jeep Cherokee... I had a weak battery and it suffered from the same symptoms. I would start the car on a cold morning and it would die promptly after until the battery charged back up from the alternator. Best thing to do is take it back to your mechanic and explain that either the battery or the alternator isn't working properly. They should fix it for free.

 

[djheater]

It is the alternator and it's being replaced. Why would that cause the car to rev really high in neutral?

 

[Quixfire]

Originally posted by: djheater
It is the alternator and it's being replaced. Why would that cause the car to rev really high in neutral?

As stated above:

Most idle control devises use a 12v power supply to control the idle, if your system drops below 12v then it wouldn't work correctly and your idle could be higher than normal.

 

A low voltage at the ECM will cause erratic engine function.