Aac Valve Is Missing From My Car

[Proximity Motorsport]

Hey,

I just purchased a R32 with RB25 in it. It has a Microtech ecu. Now the standard plenum was removed from car when i bought it, and a greddy copy was dummy fitted. After inspection, the standard plenum has a plate over where the AAC valve went, and its been sealed, and the new plenum, which owner said was purchased second hand, has had the hole welded up, and im confused as i dont know how the car will idle? I dont know a single thing about microtechs..but to me i would think you will need air somehow to make it idle.. Any Ideas? Anyone know of removing aac valve how to keep car running??? Problem is i havent started car yet cause its all in bits, and ive never heard it running

[bradsm87]

Maybe the microtech doesn't do electronic idle? If so, just adjust the throttle stopper to get the right idle.

[Proximity Motorsport]

you mean so the throttle only closes 98% or something.... i heard this can be bad when you back off, the revs dont drop quick enough?? true or false anyone?

[08yannch]

it is just the throttled body has been adjusted so that it is always open. this does not mean that it is all of the way open is may only just a little. i dont think it will damage any thing when u back off as long as ur not idling to high. but dont take my word for it.

the way that i see it is if nothing bad has happened and there ar no funny sounds then it should be fine

[unique1]

i run an rb26 with aftermarket ecu and the aac isnt even plugged in or workin and it idles perfectly

[PM-R33]

I'm a bit curious about this aswell. On a MAP based ECU, do you need the AAC? Mine uses one at the moment, but i wouldn't mind getting rid of it to neaten up the engine bay if i could....

[BrynDETT]

no you dont need aac... atleast that has been the case with a 4agze ive been working on... its running a haltech map based ecu.. so obviously the haltech didnt support aac so we blocked up the idle control holes in the throttle body and just set the idle with the idle screw... works like a charm..

[Richieb]

If aftermarket, it prob not used or needed. If like mine, its just closed right up, and disconnected(for future)

[nizmonut]

The Auxaliry air control valve is there for the purpose of adjusting the idle under load of air conditioning or alternator load, it adjusts idle up to 500 rpm, the ecu also uses it to determine engine revs at idle whilst warming up, however it is not critical to the performance of the engine as it becomes redundant once rpm reaches 1500.

[Richieb]

Yeap, and the A/Market does this for you without AAC valve, if setup correctly.

[PM-R33]

Hmmm might talk to my tuner once the car is back on the road and see if he says i can get rid of it. Less hoses/wires the better

[MBS206]

If your aftermarket ECU is running the AAC valve, leave it on.

To get a car to idle up without one, means you have to fudge things with timing.

To force a car to idle up, say if RPM drops to 600RPM, you throw ALOT of timing in, and it'll bump it up. If it's idling high, you reduce timing so it drops down. It's all in tuning the timing map, and fuel map to make it idle correctly.

Things you will lose though, are like the idle up when you turn the steering wheel, or turn the AC on or lights on.

Some ecus allow you to add or reduce ignition timing VS temperature, this is how they can idle up, when cold. But nothing else can be idled up.

You can do this whether the ECU runs an AFM, or a MAP sensor. You just need to know how to make it do it.

Last I heard, the Microtech can't control very many AAC valves. But if your ECU can, LEAVE IT ON THERE! It'll make life alot more simpler then "removing a few hoses"

[Proximity Motorsport]

thanks alot for the help guys, that sorts me out, My car never had one when i got it so i wont bother trying to hook one up, when i get it running i just hope she runs alrite, thats alot... if i have trouble with the A/C or the P/S stalling me ill just bump the revs on idle to 1000rpm or something.

Thanks alot for the help, Happy new years

ps...just for the record my old r32 had map sensors power fc djetro and it needed the aac valve, but when it was fully open was still not getting enough air so i left it on, but i also opened the throttle a little.

cheers