Diy Aac Valve Cleaning & Idle Reset.

[spec-V]

I have done this mod also!

Great success, never had any idling issues, but now feels alot more responsive!

[NISSANR33GTST]

hi guys, can any one explain how these valves work on the rb25 s2. i have a full aftermarket ecu that i need to wire and so i need to know which way to set them up

thanks any help witll be great

[The Scientist]

Hi,

I'm having some idling issues and was just wondering is there anything I need to know before attempting this on an R34 GTT or is it basically the same? Also, I have a Power FC fitted. Will doing this affect my current map at all?

Thanks.

[damuscat]

Hi,

I'm having some idling issues and was just wondering is there anything I need to know before attempting this on an R34 GTT or is it basically the same? Also, I have a Power FC fitted. Will doing this affect my current map at all?

Thanks.

I actually just completed this on my R33 and it vastly improved the idle. I also have a power FC and it didn't affect anything.

[The Scientist]

I actually just completed this on my R33 and it vastly improved the idle. I also have a power FC and it didn't affect anything.

Thanks, I'm going to give this a go tomorrow so.

[Josh33]

just did mine, took about 1.5 hours (pretty thorough cleaning)

hardest bit was getting the bottom hose off/on

exellent result- no more hunting idle and feels like a much smoother drive also

much thanks for the awesome write up- made it very easy

[Jum]

Pics dont work anymore

[blags]

I really need to do this, gonna attempt it tomorrow. Great write up btw. Thanks

[Jet 20]

hey all,

did this on my rb20det this arvo, very very easy on the 2 litres. not half the amount of junk to pull of.

one wire connector, one hose and four bolts.

the solenoids dont have o-rings under them on this type either. it has a different seal setup inside.

only has one spring back inside the solenoid, one spool in the valve and the idle screw.

mine was idling pretty good to start with but it was full of crud.

also i just counted the amount of turns when removing the idle screw, cleaned it all then screwed it back into the same position and the idle was unchanged.

seriously only took 15 minutes.

[br3ndan]

yesterday my car suddenly was idling at 1000-1100 rpm... had a search around on the forums and came across this DIY.

Had a go at it today and hey presto it fixed the problem straight up!

Cheers Insu...

ive also noticed the thread has helped a heap of people since 2006... not a bad effort at all!

My hat comes off!

[HEKT1K]

did this today as i had some idle/stalling issues - wonderful write up made it very easy!

thanks a lot

[Gaspard]

AAC valve eh...

I have noticed hunting when using A/C and power steering etc...

Occasional stalling when coming to a stop with A/C on or coming around a corner.

I had figured it was down to an old oxy sensor as that is common on other cars, but this sounds like a quick/cheap and (relatively) easy fix.

I'm now planning on doing this cleaning procedure later this week.

Series 1 Stagea (RB25DET) R33 equiv.

Since these don't have a manual option, mine is Automatic. Just wonder what the suggested idle is for automatic?? 900ish or lower/higher

Cheers

PS: The inline pictures show as URLs and a bunch of thumbnails below the post... the URLs open a broken popup window (which if you replace "image-cache." with "www." then it works)

PPS: To all RB Turbo owners, if you have not already replaced or fixed the coils on your car, do it now, it helps a lot, $2 tape for the poor, $20 silicone for the smart, $1000 Splitfires for the rich

[Gaspard]

I'm now planning on doing this cleaning procedure later this week.

Done!

It was a lot easier then I thought it would be, the two hoses attached to the AAC valve assembly don't have to be removed until you've taken all the 3 bolts out, then you have "wiggle" room.

The 3rd bolt is not visible but there was just enough room to get a small 10mm spanner in there and crack it then take it out with socket.

Used WD-40 to loosen up the vacuum tubes and a screwdriver to pry them a little, came off pretty easy.

used heaps of carb cleaner on the valve body... the idle adjust screw, counted the number of turns when removing it and put it back to the same setting. (15 full turns on mine, if you were wondering)

the idle adjust screw plastic collar was not too bad, makes the screw stiff to put back in but it does go in... seemed to be a flathead/Phillips number 3 combo screw, looks like you could strip it pretty easy with bad tools.

The o-ring was blue on mine, pretty good chance of losing it if you're not careful, be sure you pull the solenoid off in a clear area so you can see it if it falls..

push the valve in and out when you're carb-cleaning it to get all the crap out of it.

I dropped the 3rd bolt into the engine bay when I was reassembling it... but luckily it made it all the way down to the ground... whew!

Valve works smoothly now, I'm guessing my occasional stalling will be a thing of the past.

[sly32]

hey guys, so i havnt done this atm but i am going to,

ive just put a rb25 series 2 into my r32, it idles at 750 once warm, and for me that is to low because i can stall it with a brake and clutch in, so i want it to idle around about the 1000rpm mark,

so i saw that you can adjust this with the ecu because no metter which way i turn the screw on the aac it wont change the idle, so maybe a clean might help,

but this screw on the ecu, i know what your talking about, but mine doesnt have that or the light? wtf, any chance i can take a light and a screw thing out of a spare ecu i have and solder them into the correct postion?

from what i can see it has the right marks to ment to have 1 so i dont know there isnt any in there?

any help would be good,

Thanks

[SLY-25T]

just finished doing it to my car. perfect idle now and smoother revs.

great write up. recommend to everyone that wants to do something to their car but cant think of anything.

[sly32]

any1 can help me? i cleaned it all out, was heaps of crap in there, cold start works well now, but i adjusted the idle screw and can only just get it up to about 800max, i dont have the control on my ecu, i think i have a ecu from a series 1 rb25? can i use this cause i know this has the control in it?

Cheers

[(B1) MR_fanny]

mine started idling at 1700 then drops to 1400 at a complete stop a couple days ago. exhaust gave me a headache everytime i was at the lights cause it was reving so high.

cleaned it up tonight in the dark with a spotlight which goes to show how easy it was with the help of this DIY. I used the subaru engine carbon cleaner which worked quite well. Make sure to give the spring a good spraying and blowing as i think thats the reason why it played up in the first place. couldnt see teh gaps between the spring when it was dirty. Still using the old gasket and no problems so far.

thanks again for the DIY

[studricho]

Great thread and read. I've been having idle issues with my RB25 engine, but after having a look at this thread I decided to clean the aac valve, but I don't think I have the room in my engine bay to remove it.

It looks like i would have to either take out the wiper motor (huge task in itself) or drop out the engine.

Remember my engine is in a torana..

Anyway i decided to remove the hose that goes back into the cross over manifold and spray subaru upper engine cleaner in it. This stuff works better than any carby cleaner on the market.

Put it back on and start it.

So far, so good. no more idle issues, no more stalling when I stop or back off. I've driven the car for about an hour and it would of have this issue within 10 mins.

I thought I'd post up another option to clean this without removing it.

Thanks again for this thread.

[banhzSIIR33]

just did this clean this morning... was quite easy job to do... bitchiest part was putting the bottom hose back on..

to take off the 2 bottom bolts... just get a size 10 socket and a short extension thing to undo them... quite easy..

had to use all my arm strength to take off the bigger hose.. good thing im buff...

my idle screw went a bit stiff when i was trying to adjust it but it was about 800-900 neways...

before the clean i had a bit of hunting and only stalled wen drove up my drive way (slight incline) and stopped...

but thats all pretty much disappeared now.. great write up... much appreciated...

every1 should give it a go...

[iseekool]

Has anyone done this to an R34 N/A (RB25 NEO)? I've had a look at mine and it seems quite different to the R33 in the pics.

I have no issues with my car at the moment.

I'm just curious - because I wouldn't mind cleaning it, for the sake of keeping it maintained and I imagine it would also help with idling economy too.