Strange Electrical Phenomena pt 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

/etc/shadow · 12-13-2002, 09:46 PM

A while ago I noticed that my euro-style indiglo gauges and headlights would tend to go dim after I idled for a while, but if I revved up the engine, they would get bright all of the sudden. Gradually had depleting power. In short, the alternator was gone. Car was running at 10 volts while IDLE!

So I replaced the bastard. Now, the car runs at 14 volts and 13 when off, but the gauges and headlights still tend to get dim. What the heck is going on?

BTW, I forgot to add that eventually on the old alternator I couldn't drive at night well because it would die at idle with headlights on if left like that for long. The new one, well, I was in a traffic jam with all accessories full on - gauges, headlights, defrost, blower, radio, and while the gauges and lights dimmed out a bit, I never stalled or stumbled. Autozone checked the new one and said it worked perfectly.

hookedup240 · 12-14-2002, 08:57 AM

Do you have a powerful system cause in my car i have so much power being taken from the battery everything in my car dims even in the daylight i can see my clock dimming while driving.  If this is the case, just don't play your system at night while stopped.

mrdirty · 12-14-2002, 10:21 AM

A shot battery will kill an alternator; and having a serious system in the back could kill both.

If you have a system:
-check all connections for shorts
-check to make sure your amps are hooked up correctly and the speakers are ok.
-check all grounds for alternator, amps, gauges, battery...

If it dims w/ a bass hit (run a bass test cd at night w/ all accessories on) then you're drawing more power than the alt can supply, a capacitor would help a lot.

If you don't have a system I would begin checking the electrical system for something drawing WAY too much power; use the old trouble shooting tech by unplugging one thing at a time until you've found it.

ridebmx · 12-14-2002, 02:21 PM

if u have a big system you could always run on or 2 more batterys, and i know they make really high output alternators for other cars, not sure about the 240sx, look into that...another thing u can try is getting a really good battery, optima batterys arent bad, and you can mount them whatever way u want...thats it from me, if it didnt help...well then i dont know what else to tell ya

Nerfdude · 12-14-2002, 11:30 PM

yeah, if you have a system, get a cap... i've got a .5 farad rockford cap, i'm about to upgrade to a Monster Cable 1 farad cap... the .5 helped a lot, but there's still a little dimming when it's turned up really loud. w/o the cap, my headlights would go almost completely out under the same load...

mrdirty · 12-14-2002, 11:45 PM

the rule of thumb is one farad per thousand watts RMS.
I run a single 1 Far cap for my sys and it's well over 1600 rms; no dimming...

12-14-2002, 08:57 AM	#2
hookedup240 Zilvia FREAK! Join Date: Dec 2001 Location: NJ Age: 41 Posts: 1,149 Trader Rating: (0) Feedback Score: 0 reviews	Do you have a powerful system cause in my car i have so much power being taken from the battery everything in my car dims even in the daylight i can see my clock dimming while driving.  If this is the case, just don't play your system at night while stopped. __________________ 1991 240sx se 5spd - sold 2003.5 Mazdaspeed Protege

12-14-2002, 02:21 PM	#4
ridebmx Zilvia Junkie Join Date: Mar 2002 Location: Michigan Age: 41 Posts: 379 Trader Rating: (0) Feedback Score: 0 reviews	if u have a big system you could always run on or 2 more batterys, and i know they make really high output alternators for other cars, not sure about the 240sx, look into that...another thing u can try is getting a really good battery, optima batterys arent bad, and you can mount them whatever way u want...thats it from me, if it didnt help...well then i dont know what else to tell ya __________________ I like my car, you may not...You like your car, I may not...To each there own, right? waiting for the sunken look to be cool..lol

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12-13-2002, 09:46 PM	#1
/etc/shadow Zilvia Member Join Date: Jun 2002 Posts: 167 Trader Rating: (0) Feedback Score: 0 reviews	A while ago I noticed that my euro-style indiglo gauges and headlights would tend to go dim after I idled for a while, but if I revved up the engine, they would get bright all of the sudden. Gradually had depleting power. In short, the alternator was gone. Car was running at 10 volts while IDLE! So I replaced the bastard. Now, the car runs at 14 volts and 13 when off, but the gauges and headlights still tend to get dim. What the heck is going on? BTW, I forgot to add that eventually on the old alternator I couldn't drive at night well because it would die at idle with headlights on if left like that for long. The new one, well, I was in a traffic jam with all accessories full on - gauges, headlights, defrost, blower, radio, and while the gauges and lights dimmed out a bit, I never stalled or stumbled. Autozone checked the new one and said it worked perfectly.

12-14-2002, 10:21 AM	#3
mrdirty Zilvia Addict Join Date: Mar 2002 Location: Thunder Bay Ontario Age: 47 Posts: 650 Trader Rating: (0) Feedback Score: 0 reviews	A shot battery will kill an alternator; and having a serious system in the back could kill both. If you have a system: -check all connections for shorts -check to make sure your amps are hooked up correctly and the speakers are ok. -check all grounds for alternator, amps, gauges, battery... If it dims w/ a bass hit (run a bass test cd at night w/ all accessories on) then you're drawing more power than the alt can supply, a capacitor would help a lot. If you don't have a system I would begin checking the electrical system for something drawing WAY too much power; use the old trouble shooting tech by unplugging one thing at a time until you've found it.

12-14-2002, 11:30 PM	#5
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	yeah, if you have a system, get a cap... i've got a .5 farad rockford cap, i'm about to upgrade to a Monster Cable 1 farad cap... the .5 helped a lot, but there's still a little dimming when it's turned up really loud. w/o the cap, my headlights would go almost completely out under the same load...

12-14-2002, 11:45 PM	#6
mrdirty Zilvia Addict Join Date: Mar 2002 Location: Thunder Bay Ontario Age: 47 Posts: 650 Trader Rating: (0) Feedback Score: 0 reviews	the rule of thumb is one farad per thousand watts RMS. I run a single 1 Far cap for my sys and it's well over 1600 rms; no dimming...