I recently had a trip to the dyno in which I discovered numerous electrical gremlins that possibly could all be related. What I need are suggestions on how to trouble shoot or an order of operations on what I can do. Right now I dont know where to start.

The problem:
Under load my voltage will momentarily drop from 14.4v to as low as 12.5v, it will then recover back to 14.4v only to drop again. The drops don't seem to correspond to any particular system coming on line, but the drops are very noticeable and even dim the dome lights, headlights and gauges. I also experience a voltage drop at idle with 750rpm voltage dropping to 11.8v.

I have a relocated battery to the passenger side rear bin (westco Miata battery). I have a brand new engine wiring harness, and a brand new high output 150amp alternator. The alternator is currently running a stock pulley and stock eshaft pulley (not underdriven at all).

I am willing to so far as buying a new chassis harness and charging harness if I know this will fix the problem. However, I would like to know what I can do to attempt to trouble shoot before having to go to that great a financial outlay. I will be adding a halo of grounds to the engine bay as a first step. Any ideas on what else I could do would be appreciated...

Regards,
Brian Kraemer

 

Nobody?

 

do u have any voltage drop from the alternator to the battery? check the battery ground and alternator ground also

 

Sounds like grounding issues.