Running out of Voltage @ WOT....WTF!? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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)

02-11-2009, 07:56 PM	#1
MandTPhotography Zilvia Addict Join Date: Jul 2008 Location: Wilmington, NC Posts: 801 Trader Rating: (2) Feedback Score: 2 reviews	Running out of Voltage @ WOT....WTF!? 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.

02-13-2009, 08:39 AM	#4
Teambadrun Zilvia Addict Join Date: Jan 2007 Location: Melbourne,Australia Age: 46 Posts: 642 Trader Rating: (1) Feedback Score: 1 reviews	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!? __________________

02-12-2009, 04:20 PM	#2
Este510 Zilvia Member Join Date: Aug 2006 Location: Cali Age: 44 Posts: 214 Trader Rating: (2) Feedback Score: 2 reviews	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.

02-13-2009, 07:23 AM	#3
MandTPhotography Zilvia Addict Join Date: Jul 2008 Location: Wilmington, NC Posts: 801 Trader Rating: (2) Feedback Score: 2 reviews	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.

02-16-2009, 01:55 PM	#5
MandTPhotography Zilvia Addict Join Date: Jul 2008 Location: Wilmington, NC Posts: 801 Trader Rating: (2) Feedback Score: 2 reviews	Bump for confusion. Is it possible my AFC is going retarded?

02-16-2009, 02:15 PM	#6
Phill Join Date: Nov 2008 Location: va Age: 34 Posts: 19 Trader Rating: (0) Feedback Score: 0 reviews	Maybe a grounding issue?

02-20-2009, 11:29 AM	#7
MandTPhotography Zilvia Addict Join Date: Jul 2008 Location: Wilmington, NC Posts: 801 Trader Rating: (2) Feedback Score: 2 reviews	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)