348 spider battery light

Friend has a baffling problem: 348 spider with Nippondenso alternator. Car will intermittently flash the "batt" light when running pretty hard, at higher speeds, like over 100 mph. Just accelerating to redline through the gears will not necessarily get the light to come on. Running it to higher rpms combined with higher mph does get the light to come on occaisionally. Alternator was rebuilt, and upped slightly in output, and an additional cable was added from the alternator to chassis ground. Anyone have an idea where the next step might be in fixing this? I was thinking that perhaps where ever the sensor is located that trips that light might need the ground cleaned or another ground added....or is that built into the alternator?

<<Alternator was rebuilt,<<

I've seen on a few occasions the light flashig/blinking in concert with revs. In every case it was a rebuilt Alt with the wrong regulator. A switch to a quality Heavy Duty reg. cured the prob. in every case.

Regards, JRV

Ditto to that JRV. Every time my rebuilder touches a 348 or 550, we go through this problem. The correct parts must be used, no generic.

Regards, Brian

Thanks guys, I will pass the information along.

JRV what kind of heavy duty regulator would you suggest for a 348 nippondenso? I had my alternator rebuilt and it has had this same problem. It's fine but under heavy acceleration at the higher rpm's the light does come on.

Ernie,

I don't know exactly..like Brian..my alt shop has rebuilt a number of these alt's and when I reinstalled, had the flashing light, took them off &amp; back to the alt shop they simply told me that they had to install a special heavy duty regulator....whatever they did solved the issue in every case, so I took the heavy duty reg story at face value. I do know for a fact that the regular generic regs they tried to use caused the blinking light problem. My take on this is that ther are expensive &amp; less expensive replacement regulators and the cheaper ones don't work properly.

Regards, JRV