Electrical problem

[branthedon]

I just recently got an 89 GT vert that had a few mods and a bad alternator and battery when I got it. I've since replaced both, but something is still off, the alternator doesn't charge sufficiently at idle, it seems.

The mods the car has as far as I can see are an MSD distributor and coils (I see a red MSD-branded metal box on the fender a few inches away from the battery, that's just a guess) and Pioneer head unit.

I was wondering if the upgraded MSD components increase the amount of power needed from the car at idle. Also, if this is the I should get a higher output alternator, a smaller pulley or an amp (I'm guessing the amp because I just thought about the car possibly also having upgraded door speakers).

Another note: I usually don't even drive the car with the stereo on, because driving is actually difficult when it's is. Pulling off from lights with the heat AND stereo on makes the car hesitate at really low speeds, making me stall a lot.

 

[Wicked One]

Need more info.

What is the voltage at the battery at idle?
How is the stereo hooked up (are there capacitors, how many amps, etc..)
Do the headlights dim when the stereo or any high draw (a/c, defrost etc...) are on.

You are local to me. if need be I will look at it. I like electrical work, makes me happy

 

[branthedon]

I can check the voltage tomorrow, but I'm not sure how the stereo is hooked up, it was installed by the previous owner. The lights do dim and the idling gets rough when the stereo or a/c is turned on. The car comes pretty close to shutting off.

 

[branthedon]

Need more info.

What is the voltage at the battery at idle?
How is the stereo hooked up (are there capacitors, how many amps, etc..)
Do the headlights dim when the stereo or any high draw (a/c, defrost etc...) are on.

You are local to me. if need be I will look at it. I like electrical work, makes me happy

I haven't checked the voltage, but the head unit has a 10A fuse in the back of it, so I guess it means it's a 10 amp unit.. And it looks like it was hooked up through the factory connections. And as a note, at idle the headlights and interior lights aren't at their maximum brightness, they only get so if I rev the engine.

 

[branthedon]

Found the problem, car was idling too low for the alternator to be useful. Was probably at the default setting, just a hair over 500-ish rpm, so I raised it to about 800rpm. Runs like a top now. No more surging, either.