Cruising tonight, the lights turned on and off. 20 sec later same thing. I pull into my cousin's house 3 min later. I sat there idling and turned on and off again. After that, the lights flickered like a strobe light and eventually the ABS light came on and the headlights/dash lights were fine.

I went home and put a Fluke multimeter to check things out as far as my voltage goes. Battery is new, Optima Yellow top.

Car's off: ~12.5v
During start: no less than 11v (so I assume the battery is good)
Few seconds of high idle after start: ~14v
3 min after start: progressively goes from ~14v to ~12.48v
Playing with the throttle cable to hold it ~1100rpm: 13-14v+

Idle is around 700. I tried everything I could with my ECU tune and TB adjustments a while back to keep it at 800-1000rpm because of my JRSC but it wasn't happening.
OT:
CROME P28
70mm Blox TB

Obviously the alternator is supposed to charge the battery, but I'm sure at lower rpms like idle it would not be ~14v right? I believe what it's at is normal but that was my only diagnositc today since it is night time.

 

I would replace the alternator. sounds like a bad votage regulator in the alternator. if it was a overall bad ground, you would have all the dash lights on and dead pedal feeling during partial throttle. Could be the ECU, but if the car is running fine and you dont have a dead throttle feeling, then I would think it is the VR.

 

Car drives fine. I doubt its a ground because I have an HKS Cirlce style system in my car.

Does my voltage look bad for the specified rpms though?

What sucks is the JRSC is special with the alternator. Alot of you probably don't know but even though the body and the pulley may be the same with the other B series the shaft is different. People with a JRSC have to replace the pulley with a double alternator pulley. I got a stepper pulley made by MVM motorsports. The 1 man businessman, Jim, said the shaft is I think skinnier on the B16 and I would need an adapter sleeve to put in there.

I haven't replaced an alternator in my DC2 before but have in my DA plenty of times. In the DA I can pull the alternator out easy from the bottom. But not with the DC2. Will I be able to pull it through the bottom?

 

yes, it comes out the bottom.
my point was that I dont think it is a ground issue as that would manifest in drivability issues (which you are not having)
so that points to a voltage regulator issue which ties more directly to headlights and dash lights.
I did not realize the alternator has a JR specific pulley. the AMP requirements must go up considerably because of the SC.

and no, your readings look good, but you would have to log the voltage to see what happens when you have a headlight flash. Can chrome do that?

 

I don't know if crome can do that. Why would the amp requirements go up? The only difference is physical drag from extra stuff to turn, not necessarily powering more items electrically.

 

Drove alot tonight, no issues.