Did my alternator fry my computer?

Jump2xs · 09-30-2004, 03:19 PM

the subject car is my buddys 1984 944 (which used to be mine)

Here's his story:
My alternator bearings took a dump out in the desert, but I decided to drive it as far as I could. All the lights got bright and my battery was apparently over charging.
Finaly the car died. I then replaced the alternator, and all the relays and the coil.
The car cranks and seems to be getting fuel, but it won't start. The radio, turnsignals , emergency flashers won't work either, even after replacing the fuses.

Did I fry the computer?

IceShark · 10-01-2004, 01:49 PM

You may have. I think your problem was you killed the voltage regulator and let the voltage run wild on the high side. Depending on how long you ran this way and how high the voltage got a lot of things that were designed for somewhere around 12 to 15 volts could have gone south.

Bulbs for sure, just check them to see if the filament is burned in half. Since you said they got brighter you can rest assured voltage spiked. And a bulb won't last long if you overvolt it. Maybe even minutes if you got voltage high enough.

I'm not exactly sure how much your '84 DME/ECU (computer) can take in overvoltage before you fry it but I have seen it once when a tow truck put the charger on 24 volts and jumped a car. That was all she wrote. Probably the same for your radio. And fuses usually won't protect you from an overvolt situation as they are just thermal. And as you may have just found out.