AAC Valve Problems on Rb20

[StylezTA]

OK so my car surges really bad. Ok, Vacuum leak. Found one under the TB. Found another behind the engine. Its still doing it. I can hear a SUPER loud hiss from the Aac valve. I get the idea to unplug the aac valve... it literally stops and starts idling at 1100-1200. Would this signafy a bad valve? I can't find anything else leaking and this is keeping me from driving this thing lol. Let me know what you all think

Brandon
Modified by StylezTA at 9:22 AM 11/6/2008

[eh?]

Sounds like it's hunting for idle. Is base timing right and are the throttle position sensors set up right?

[StylezTA]

honestly i have not messed with timing or tp sensor. i bought the swap out of a buddies car i saw with my own eyes run perfect. why would hte idle smooth out instantly when i unplug that sensor?

[eh?]

honestly i have not messed with timing or tp sensor. i bought the swap out of a buddies car i saw with my own eyes run perfect. why would hte idle smooth out instantly when i unplug that sensor?

It could be messed up as you said . But I don't think it's the valve. The ecu commands that valve to move, so If there is a vacuum leak the computer will try to correct by moving that valve. By doing do it regulates the amount of air going into the manifold. If the valve oscillates, RPM will oscillate too. The computer will also try to compensate for base idle rpm changes too by moving that valve. If it all of a sudden happened, I'd look for more vacuum leaks.

[StylezTA]

ok i will keep you all posted. thank u for quick responses

[StylezTA]

ok i will keep you all posted. thank u for quick responses

[StylezTA]

ok i will keep you all posted. thank u for quick responses

So was screwing with the car last night and decided to take the aac valve off just to get a better look at the lines and such in that area. i noticed that the 2 screws that hold the "head" of it on were loose and the tabs where bent? Wtf? take those 2 screws out and the lip on the inside of the valve was completely cracked, let alone it looks like there should be a gasket there.... which there wasn't! So i need a replacement valve whether this is the problem of not. this one was obviously broken by last owner and just thrown back on the car bad. GREAT. I'll try and get pics of it up tonite.

Who can tell me where to get a replaced aac valve for an rb20? I heard a single cam KA's is the same but not sure. Let me know! Thanks!

Brandon

[hellboy006]

I think its the same on ALOT of nissans, the vg30's in the 300zx's use the same one aswell, i just picked up a new AAC unit and air reg from RockAuto for a little over 200 for both, fixed all my idling problems. Your RB was manufactured around the same time, i bet it uses the same one. But i would verify with an RB owner before you sped the 2XX$!

[KoshiLe]

I kind of have the same problem. I pulled the hose, and when its completely blocked off its decent like you said 1000-1200. Another thing is that i adjusted the idle screw on the AAC valve, its almost completely in, but will idle the same.

And when i screw it completely out.. it still doesnt change idle.

TPS sensor is wired correctly, i confirmed this by hooking up the TPS, then looking up the MAX and MIN voltage on the Emanage ultimate software.

Currently Running Greddy plenum and Q45 TB, i hear a vac leak under the throttle somewhere, cant quite pinpoint. but its hissing pretty good. i did the spray can test.... no luck