Since I have to pull the alt to change everything I'm just going to build my spare alt and drop it in. The new grounds on the car are all fresh and overbuilt.

New ground by old ground.

 

hmm... ok i take it its a ribbed belt correct 6 rib i think ?? also what is the diameter of the output shaft ?? i might have an idea

 

 

this might solve your problems





and log on already dang ! and dont talk about my counter tops lol

 

Dude that is way too small IMO. I'm gonna spin the dang bearings out of it. LOL. I think 1/4 inch smaller than stock would be perfect. I dunno about that one, I need to do some numbers to see what the increase would be.

(not on the laptop with Aim right now)

 

um, have you even checked voltage at idle? or amperage output of your alternator???

675 rpm is fast enough for the alternator to create proper voltage and current with a properly operating voltage regulator and battery... (yes, a bad battery will cause this same issue you speak of)... idle specs call for 650-750 rpm and the alternator should be able to maintain correct voltage and enough amperage to operate everything in the car at idle speed...

what voltage is the alternator outputting? what amperage under load is it capable of? how old is the battery and what is its reserve capacity (not what it's rated at, what it currently is)

 

Tks for the ideas, but I am hours ahead on this angle.

Re: the regulator; I've already blamed the regulator in my suspicions, but it seems to be a threshold issue with it. It works fine otherwise.

 

i'll throw my two cents in here.

at idle in gear, my idle drops to about 580rpm. if it's at night and i have my hid lows, hid fogs, and wideband all running, if i idle for too long, eventually the wideband will be starved of power and throw an error code. while this is happening, my afc is displayin a voltage of 11.5 and drops the longer i idle around. once i get on the throttle, it easily goes back up to the 14.1 area.

i'm guessing it mite just be a low idle issue and i may just raise it to see how it goes, but i'd like to try and figure out the real reason. as for battery, it's an optima relocated to the trunk, connected with 0 gauge for both ground and positive. alt is a rebuilt 200amp alt.

 

Wow 580. That must be all those HID's. Every time I turn something else on I drop 50 to a hundred RPM until I have enough on to show a real load. Even then, I only get to 675 running bone stock.

 

it honestly sounds like you guys have alternators with low amperage outputs...

my alternator outputs over 40 amps at idle (just under 700 rpm) and 14.3 volts

at 2000 rpm, and a full load, it outputs over 70 amps...

the alternator should always output 14ish volts no matter what engine speed, thats the job of the regulator - but it has to have enough amperage to keep the battery charged, if the battery gets low on charge, the regulator drops its output as well... so, I'll ask again, have you checked the amp output of your alternator???

 

lol too small naa youll spin the bearings if you turn the motor to 10k rpms

 

I'm not sure about how the 1UZ is, but when I picked up a pulley set for my 2JZ it had a smaller alternator pulley and a larger power steering pump pulley so the belt length would stay the same.

 

I am an alt. rebuilder, and I agree with mitsuguy about making sure the battery is good. An alternators voltage output drops with rpm. just like h.p. and torque do. When all is right with the car the alt. should remain at around 13.2 at idle which is why usually you are drivind down the road 60 mph with lights and a.c. on and the voltage runs at max. of 14.5. You shouldnt have to increase pulley dia., just find the weak link in the charging system. I would first get the bat. proffesionaly tested then move to the alt. If the alt. is to blame, prob. more than just the reg.

 

I also replaced the main ground cable on my 95 and cleaned the firewall ground, in hopes of clearing up a slight hesitation, which it did not. I believe there is another ground wire to clean or replace but am not sure where it is. If anyone can say where it is on the sc400, we would both benefit.

 

As stated before, this aspect has been covered. It's a new bat and alt. The regulator was reused.