The 140 amp alternator can't keep up? With my AC fan on high electric fan stereo and head lights My voltage drops to around 12.5. Seems like the AC blower and clutch takes the most out of it. If I have the AC and blower off voltage stays at 13.x or so?

Also now my tach jumps eratically around at lower rpms since the swap?

I'd assume 140 amps should be hella overkill. Any tips? I just connected the field wire on the GM alternator to the brown wire in the mazda plug end that was pugged into the back of the original mazda alt. I checked it with my meter and it switches on at bat voltage with IGN.

With all accessories off it comes right online at startup and charges at 13.6 like it should The AC clutch and fan zap up all my voltage?

Any pointers?

Should I not worry as long as I'm not droping below 12v? Seems really strange I would haev thought this alt could hae powered a small country?

thanks!

 

well a while back i had a tach jumpin problem but it was the plug that was loose on my dist.

also possibly is your battery old?

 

I'll check my plugs. Battery is less than a month old. $130 Optima red top. shoudn't be that!