SR20DET voltage dropping when under electrical load

[Quiche2192]

Originally Posted by jr_ss

What are the discharge amps of your alternator? Assuming it?s a stock alternator, you should have 90amps at idle.

Dunno I gotta measure it. I assume I can't measure it with a regular multi meter but I'll need a multimeter capable of measuring way higher currents than the usual 10A.
Stock alternators, yes.

Originally Posted by slider2828

I've had a similar issue of bad ground at the battery.... maybe take a pic of all the grounds you have? There should be about 5 in the engine bay.

Ok can check that and see. But I did measure resistance and voltage drop between grounds and batt negative and it does look like all grounds are good. BTW I have a Wiring Specialties Pro Harness.

Grounds in the engine bay are:
- One behind each headlight for the chassis harness
- One on the back of the engine head for the engine harness
- One on the intake header for the engine harness
- One for the MAF through the engine harness
- And then I have a dedicated grounding harness that grounds the chassis, alternator body, intake manifold, ground behind the headlights.

One thing I have noticed, I'll hear a whining sound coming from the speakers when the car is running and it kind of gets louder when I turn on the lights.

Right now, I'm thinking about removing that grounding harness to see if that makes a difference. IDK if I'm properly grounding the alternator. There's a bolt that screws into the body and I have a wire going from that to the chassis. I have good continuity between the alternator and the chassis. I don't have a good contact from the alternator body through the bracket to the engine, but that grounding wire should still be fine, right?