problems with ECU??

[geoff-9]

wondering if anyone can help diagnose this.

when i was going to work the other day the battery warning light came on in the car, by the time i get to work the headlights have dimmed and the dashboard lights are dim, so im thinking its the alternator

i get back 10 hours later and the car starts without a problem but still has the battery warning light on. so i assume its just a sensor.

about 5 min later and as soon as i get on the 427, all the dashboard warning lights such as handbrake, abs, alarm, oil pressure come on, then the dashboard lights go out, headlights go off, gas limit indicator goes down, and the car feels like its out of gas so jerking back and forth... then the car dies.

i try and start it, it starts fine but then dies instantly, does this a few times. my dad brings a new battery he had when he came to rescue me, we put it in and same problem, so got it towed.

any idea what it could be.. is it the ecu, car is a 97 cavalier 2.2LE

[vgames33]

If the battery light is on, the alt is putting out under 12 volts DC. On a '97 cavalier, the alt/battery light should be controlled directly by the voltage output of the alternator. The other warning lights most likely came on from a low battery voltage (dead alternator with some driving).

When a battery dies, it drops to a low voltage. After sitting, the voltage should rise as the battery temp drops, explaining the restart. I had this problem with an older car ('83 Oldsmobile). I got a jump and made it about 5 blocks before the battery died again at a gas station. I would check the battery, alternator, and wires (a fresh battery should have gotten you home).

I doubt your ECM is bad. Test the battery, alternator, and wires (12v+, ground, and the alternator feed to the battery).

[geoff-9]

thanks for the help, the problem was a short in the alternator so you were right,
thanks