first off, for years i've been chasing down idle issues and this latest one is really beginning to annoy the crap out of me.
a few months ago i could not for the life of me get the idle down below 1400rpm. so flipping through the FSM i notice the idle is set with the AACV disconnected. so i did and BAM it idles like a champ after an IACV adjustment.
okay great, head to the dyno and call it good.
now that i'm finally driving the car regularly for longer trips than just to work and back, i have a newfound need for the AACV to be functional.

heres the situation: with nothing electrical running it will idle at 1000rpm (just as i set it). with the headlights on, radio on (nothing crazy, just a highs amp as my sub amp is out of commission for a while) and fan running on 1, 700rpm idle at traffic lights. it will drop to 450-500 as i push in the clutch initially and go back up. thats something i can deal with for now.
the real kicker is sitting in traffic or idling doing whatever and the radiator fans come on. it will jump from 300-1200rpm and eventually stall itself out.
today i had the pleasure of messing around with it and the valve and solenoid are working as they should however its still overactive. read a little deeper into and tested a basically bone stock VE that idles like a fawkin' dream. tested the voltage at the plug coming from the wiring harness and it read ~6v. okay no problem. plugged it back in and fired up my beast. tested it the exact same way and it reads ~12v.

i'm convinced this is the problem. i'm also convinced the valve and solenoid are perfect as i didnt have this problem before i pulled the motor and while it was apart i rebuilt the AACV/IACV entirely.
so my question is, WTF is causing the ECU to want the AACV open all the time? cold start with AACV plugged in yields 2300rpm, operating temp is 1500rpm so i know the IACV is working as it should (as well as having a normal cold start idle w/o AACV plugged in).
incase you're wondering i'm missing my entire air conditioning system (i unplugged the compressor on the VE i was using as a guinea pig with no difference in idle) but i dont see that having any affect on it. i'm also missing my entire PCV and EGR systems but on yet a third VE, this issue was non-existant with the same stuff removed.

so what am i to do??!?

 

bad grounds, short in the computer.

 

that doesnt sound fun. maybe i'll move my battery back under the hood. i've also got a spare ECU..i'll try that if the battery thing doesnt work

 

hi, internetautomar! U got infection from the ground? Nothing helps then but getting feet on the original good homeland ground...

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The Nissan FSM tells their servicemen not to open IACV (Thats GOOD!). The reason they tell is nasty leaks.

Well, actually no problem if u are not working for Nissan...

IACV: http://www.cardomain.com/memberpage/748507/4

Theres no solenoid, but a stepper motor. Plus a water temp controlled valve.




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haven't been to my "Homeland" in 6 years

bad grounds can cause lots of interesting problems, I had one car that would mysteriously die during some cornering manuevers.
turns out the computer was grounded through the mounting screws and they weren't in tight enough so it kept losing ground and cutting out.
only found out because I went to change the ECM and found it loose.

 

thats all fine and dandy, except the assembly is not the issue. its something sensor related, or like brian said, grounding related.
yesterday i was in traffic and it absolutely would not idle above 400rpm..and this is warm with the lights on (which typically yields at least a 150rpm fluctuation). drove for just about an hour on the highway (most of the time in the triple digits ), get to a traffic light close to my house and its idling like a dream, rock solid, 750rpm lights on, fan going, defroster..the works.
i just dont understand it!