2G voltage issue under load

[jesse_fc3]

Hey guys, i got a crazy voltage issue; when i start the car the voltage stays at about 12v, until i rev it to about 2300 rpm then voltage jumps up to 14.3v and will continue to stay at 14.3v at idle and through out rpm range until a load is put on it(ie. lights, fan, etc.) it then drops to about 11.7v-12.0v and slowly climbs back to 14.3v. Also, when im driving, coming to a stop, i push in the clutch and when the rpms fall to idle voltage goes down to about 11.7v-12.0v and the car wants to die then climbs again to 14.3 after about 3-4 seconds.
I got my alternator/battery tested at advanced and they said battery was good but alternator was bad, so i bought i new one, that one made no difference, so i then took my old alternator in and it tested perfect off of the car.
I have a few opinions from other people but i checked everything they said as much as possible and cant find anything that makes sense. I need fresh ideas.

possibly relevant mods (anything electrical in nature just in case someone knows of a common problem with one of them):

maf translator gen II with 3 in gm maf
255 walbro (not re wired)
680cc fic injectors
oem alternator (not a mod but just so you know)
optima red top battery
dsmlink v2
AEM wideband

car is 95 tsi awd

All of these have been on the car for some time now and this issue just started what seems like out of no where.
-Thanks

 

[GRAVEDIGGER]

It sounds to me like you have a problem with the voltage regulator in the alternator, but you got a new one and it didn't change anything.

You should be getting 13.5-14.8 volts with the engine running... period. If it is dipping below that you either have a bad alternator or maybe a bad connection from the alternator back to the battery.

How are you measuring the voltage? At the battery? Or do you have a guage in the car?

 

[U8NTRDY]

+1 on it possibly being a connection issue. If I were you I would grab some 4 guage and reground everything and see if that helps, as well as check all other connections.

 

[jesse_fc3]

the maft gen II has a wide variety of gauges built into it volt meter being one i also used a friends that hooks directly to the battery and his read the exact same way.
the alternator grounds itself to the block right? there is no ground cable for just the alternator is there? just the main power wire that runs back to the battery and the plug that goes into the alternator right?

 

[sniver]

Have you guys ever checked the alternator voltage in his conditions? I know mine often is 13v at idle, and 14.5 over 1800 rpm. Possibly not a improper condition.

 

[sprmotohooligan]

Try rewiring the fuel pump. My alternator did that (although not as badly, it would only dip to 12.5 at worst) and it was somewhat remedied with a FP rewire.

 

[jesse_fc3]

Have you guys ever checked the alternator voltage in his conditions? I know mine often is 13v at idle, and 14.5 over 1800 rpm. Possibly not a improper condition.

i know voltage dips under load but i know it shouldn't ever get to 11.7-12.0 with the car running

Try rewiring the fuel pump. My alternator did that (although not as badly, it would only dip to 12.5 at worst) and it was somewhat remedied with a FP rewire.

ya i should re wire it anyway so hopefully that would help some.