Seems if it were mine I'd make certain the alternator was in perfect condition before attempting to restart it. I've had bad luck several time with alternator shops putting in whatever relglators the thought may work well they didn't and in one case burnt several wires in my harness of a 123 617. For 50 bucks you should be able to order the right regulator as a start and have the alternator tested. Changing out several thousand dollars worth of computers is a frightening thought now that you know ripple is present.

Some vechiles do have factory installed capacitors but more so since the batteries are located far outside of the engine compartment and assist with load changes more so than ripple control.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10