Probably alternator but seeking opinions

[l75eya]

This is about a 93 Loyale spfi fwd.

Alternator was replaced with a remanned unit about 2 years ago.

Car has always exhibited weak voltage with things like

-fuel pump humming slower (i guess is the best way to put it) with each blink of the blinker when it's on

-brake pedal also "slows" fuel pump when at a light, not as much as blinkers though

Anyway, never really been a problem, but LATELY an inconsistantly it's been getting worse;

 

now at night, when I hit the brakes while the headlights are on the headlights will actually pretty much go out for just an instant as the brake lights come on. The instrument panel lights dim as well, briefly, as does the clock. Sometimes the radio will even go off for a second (like it does if you have it on without the car running and then start the car)

If I have a LOT of electrical things going on, I can make the car stall. I did it the other night in the rain. Headlights on, rear defroster on, windshield wipers on, sitting at a red light with the brakes on, and then I put a heavy load on the electrical system by turning the blower on to full speed. That made the car stall.

Starting in the morning, battery sounds strong. I should mention the battery was replaced as well, just about a year ago.

Sometimes, none of these things happen and everything is good to go.

Plan on making an 800 mile round trip out to pittsburgh in this car in 2 weeks so I thought maybe I would seek some opinions on something other than the alternator possibly being at fault.

If I can't replace the alt by then and you guys think that's def the problem, I have my Maxima alternator in the GL I could swap in for the trip, maybe.

I should also mention that about 3 or 4 months ago on a trip in the car to Pennsylvania there was some circuit consistantly blowing out my instrument panel lights and all tail lights in the car(the FUSE for those lights. Not the lights themselves). Only lights that wouldn't go were headlights. I narrowed that down to the license plate bulb shorting out against something and have since just removed that bulb and haven't had that problem since. Related maybe?
That's why I'm posting!

Thanks for the look!

Edited March 17, 2014 by l75eya

[idosubaru]

1.  test the alternator and see how much it's putting out.  if tools are an issue advanced auto, autozone, etc all do it for free and can test it on the car.  or take it in and they can bench test it.

 

2.  draw a line across the crank pulley with a marker and see if the line separates after some driving.  if the pulley is slipping then the outer part of it doesn't turn as fast as it should and the alternator also slows down, reducing output.

 

how's the wiring connector to the alternator?

battery terminals, cables, wiring etc - corrossion?

[l75eya]

Many good ideas here, I've been meaning to throw a multimeter at It, mine is just MIA momentarily. Never thought of that simple trick to check if the belt is slipping, thanks. Also gonna clean up all those elec. Connections this weekend.

[idosubaru]

 Never thought of that simple trick to check if the belt is slipping, thanks.

 

i hope i didn't confuse you, it's not to check if the belt is slipping.  it's to check if the harmonic balancer/crank pulley is slipping.  the rubber ring midway across (concentrically) the pulley can separate from the metal.  the outer part of the pulley won't spin as fast as it should and reduces output.  happens ocassionally, not that rare.  draw a line across the face of the pulley itself, in particualrly across that rubber ring.  if the inner metal and outer metal separate and are no longer connected, the pulley is shot.

Edited March 18, 2014 by grossgary