Dead Alternator causes over revving

[wada]

Got towed home the other day , alternator failed but warning light did not come on, battery finally goes dead, engine stuttering, I pull into rest stop and start tightening battery terminals seeing if that would help, engine starts revving by itself to 4000 rpm, coolant starts to exit the vehicle in the form of steam , WTF?

I figure the PCM was trying to get the alternator to put out more juice by revving g the engine, and maybe the fuel was really lean from injectors not working right, combined by low voltage to the fuel pump,

Just had the alternator rebuilt at a reputable shop, got another one from a 96 in the car now, pulled apart the bad one and found a brush that was messed up,

Anyway, I am putting in a voltage gauge so that the engine does not try to self destruct again.

And I am going to see if I can mount a 90 Le Sabre alt in there with some fabbed brackets because those things last forever.

[billr]

The one recently rebuilt failed (had a bad brush)? Why not take it back to the "reputable shop"?

Trying to scab in a different type alternator is going to be of little benefit. The stock Saturn units can also "last forever". You just got a bummer.

No, the PCM will not vary engine operation in response to system (battery/alternator) voltage. It is possible, though, that a very low voltage caused the PCM to get flakey and it lost control of the idle with the IAC way open.

[wada]

sounds logical.

the radio would not even come on as wells as gps.

too late to return alternator, picked up this morning by the recycle guy.

brushes looked kind of wimpy,

opened up regulator, IC had Delphi staped on it and looke wimpy also.

i might upgrade to a cadilac escalade if the rpms will mesh .

or i might just get a different car for long trips and leave the saturn at home where it belongs.