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View Full Version : Running out of Voltage @ WOT....WTF!?

MandTPhotography
02-11-2009, 07:56 PM
Just trying to figure out some things...


I have a 1997 S13 blacktop, stock turbo and injectors, Walbro 255, FMIC, etc;... all the other stuff isn't important.


What I'm wondering is WHY I am running out of voltage at WOT. I have an AFC Neo to measure all that and whatnot. When I start running out of voltage my AFR goes up, obviously.


It only happens during night-time, which would lead me to believe that there is too much draw on on my alternator/battery so I got that checked out at Autozone. Autozone hooked up the little machine thing and it said my starter/battery/Alternator was good, so WTF.


It's not so much of a problem right now, but when I put on all my new stuff (GT2871R/550/Tial38mm in my room right now..) it's not like the problem will go away...I need to find out what's up before it becomes a real big problem.

For some reason it doesn't happen in 2nd, just third and up....WTF.


Lemme know what's up, I'm so damn confused.
Este510
02-12-2009, 04:20 PM
Do you have a small battery? If you do, you might want to get a bigger or better one. Samething was happening to my brothers car while it was on the dyno at sp engineering, and that was the problem. So he bought a bigger one and relocated it to the trunk.
MandTPhotography
02-13-2009, 07:23 AM
I have a smaller battery, but it's an Optima, relocated in a steel box behind my seat and rollcage bar.


Doubt the optima is the problem, but they have a lifetime warranty, so I might swap it out.


Battery read 12.7 volts at autozone though, which is full-charge voltage.

Alternator read 14, which it should be.
Teambadrun
02-13-2009, 08:39 AM
My car used to do this aswell.

I don't know what the problem was, but it fixed itself. I hope it doesnt come back lol. I have a small battery, but it readys good voltage too. So im thinking it could be something to do with earthing out my engine in some extra spots? what do voltage experts think it could BE!?
MandTPhotography
02-16-2009, 01:55 PM
Bump for confusion.


Is it possible my AFC is going retarded?
Phill
02-16-2009, 02:15 PM
Maybe a grounding issue?
MandTPhotography
02-20-2009, 11:29 AM
I think I've come to the conclusion that my AFC Is a POS and I shouldn't beleive those readings.


My battery is reading 12.7 volts (Full charge)

and my Alternator is reading 14.0 (Normal)