Why AAC Valve up´s when 50ºdegree (Z32 300zx)

[iguanapeluda]

Hi!!!

I have my Nissan 300zx Z32 Twin Turbo Mapped during 3 or 4 years with single MAF, and the last week I installed dual Intake and remapped, but now, I have a problem that I don´t control...

When the car are between 50 and 70 degree of water, the car up´s AAC Valve to 70-80% and the car runs poor...I try to up the advance and the car goes..better...

Why the AAC valve up the percentaje??only between this temperatures..

I attach a pic of the LOG



Thnka you.

[Matt]

AAC normally goes up as RPMs drop, and closed loop idle control tries to maintain idle (around 950rpm it seems). It may not be the cause of the problem, but a side effect. You can look at your target idle RPM table to see what RPM its trying to achieve

Have a look at your AFRs also around this area and see what they are sitting around at this temperature range (I cannot see the injection time from the log so not sure if that is changing at this point?)

[Torque]

I made a similar observation:

viewtopic.php?f=8&t=3396

[Eric]

> I have my Nissan 300zx Z32 Twin Turbo Mapped during 3 or 4 years with single MAF, and the last week I installed dual Intake

what type of dual intake are you using ?
dual intake/dual MAF or dual intake/single MAF ?

dual intake/single MAF systems will not work well on a Z32 unless you install extra air balancing between left and right intake

If you are using a dual MAF system, it may be an indication your idle valve has been set incorrectly for the new setup.
(re)set it using the procedure as described in the service manual.

if the idle valve has been set correctly, but problem is still there, there could be a problem in your tune (eg. incorrectly set warmup tables)

other factors that have an influence on the aac is the neutral signal and closed throttle signal. if one of these (or both) are missing or not functioning correctly, it may cause all sorts of weird idle/aac behaviour also.