lights *still* flicker at high RPMs... please help

[fiznat]

1992 SE:

I posted this a while back and nobody had any ideas... I've got some new info now so maybe someone can help me out:

All of my lights (headlights, dome light, brake lights, etc, etc..) flicker at about 3500 RPMs, and the flickering gets worse as you climb the revs.

I was thinking a bad ground, so I tried a couple times to show a new ground by cleaning off a bit of the chassis and using jumper wire to make new grounds, but that didnt help at all. (Note: I know it was a solid ground, because everything still worked normally even with that being the only ground connected to the battery)

I got my multimeter and checked a couple things: it's digital so I cant be exact, but...

-in the dome light, voltage is actually RISING, not dropping. I was suprised by this, but it looked like it started at about 14v, and then rose up to 15v and slightly higher as the revs went up.

-Its not a funky fuse, because the affected lights are all on different fuses

-My alt is charging fine and the belt is nice and tight-- I even put on a new one because of this (it was dying anyways), and nothing changed. Is it possible that my alt is charging at varying rates?

-The battery light in the dash is also on - very dim at idle and low RPMs, and then it gets brighter and flickers at high RPMs...

-Does the 240sx have all of it's lighting wires in a specific harness? Maybe I have a bad connection or ground in there?

Arrugh this is really bothering me guys: PLEASE if anyone can point me in the right direction I'd really appreciate it!

[drift-sx]

hmmm if the volts are rising with the revs it seems that maybe your alternator is making too much power possibly a faulty one. other then that i can't think of a damn thing

[corn322]

could maybe one of the diodes in the alternator have gone out causing half a/c -half d/c power?

[fiznat]

could maybe one of the diodes in the alternator have gone out causing half a/c -half d/c power?

Uhmm could you elaborate on this one? I'm not sure how this would make the voltage at the light rise during high RPMs... Then again I'm not too good with electrical problems...

hmmm if the volts are rising with the revs it seems that maybe your alternator is making too much power possibly a faulty one. other then that i can't think of a damn thing

Yeah the alt is suspect, no doubt... but I'm confused because I had my shop test it and they said it's charging just fine... maybe they just tested it at idle and didnt notice that it charges more at higher revs? I donno...

[fiznat]

bump...

still havin this problem, maybe SOMEONE knows somethin now?

[Toahk]

If it aint' broke dont fix it!

[reu]

i've got a similar prob my car lights "all" flicker just like yours but it incrases slightly in higher rpms and now a month later my battery light flickers at idle.have u changed the battery yet?i was thinking of gettin' my alt tested and gettin' a new battery for starters and replace the alt if bad, ill tell u if i have any luck!!

If it aint' broke dont fix it!

and i wasn't gonna fix it, but now its definetly broke!

[p0onsta]

just a wildly-slightly-educated guess here,but the alternator might be about to kick the bucket, and still "charge fine"also on the assumption that your battery nearing the last of its useful life, we can arrive at the conclusion that your electrical setup is providing too little power at idle, and when revving the power actually comes back up to normal, causing the "flicker"effect.however, this does not explain why you get 14 and 15V at the dome light terminal...

another theory is that the voltage is fine and the alternator/battery works flawlessly, but you may have either too many components or have some components connected multiple times through another load. car components are connected in parallel, so you always get the full 12+/- voltage, but if there are too many components the current will be very small to each of them. check the connections of various power-drawing components, such as headunit(20 amps)/amp(40-80amps), headlights(20 amps), electric fan(20 amps), hvac(15 amps), etc.the stock alternator provides 80, and the listed current draw are for the components at full usage.

hope this helps

[fiznat]

lol back from the depths! someone was doing some searching, haha. 3 years back though, damn.

The problem was an alt issue though. I ended up replacing it even though it had passed the test-- after that all my problems went away.

[ricebike]

haha, thanx for the fixedupdate