Varying Idle, What Would It Be?

[RB20JT]

Guys,

got a problem where my idle seems to increasing then decreasing, from 500rpm-700rpm. I checked if my std BOV was leaking, and yes it...however its still plumbed back into the system as std. Would this have anything to do with it? i have checked for any other vacuum leaks or intake leaks and there r none. i have cleaned the aac valve. and its fine. what else would it be? another thing that makes me thinks its the BOV, is because when i accelerate then back off straight away down to idle speed, it drops below idle then comes back up.

does the 02 sensor have anything to do with it? i seem to be getting average 12.2 litres per 100km, thats M5 driving, so 110-120km/hr.

ur help is appreciated!

[Green_s13]

i would check your timing aswell and look for leaks

[WTFR32]

What Green_S13 said if that doesnt fix it check your O2 Sensor

[RB20JT]

i checked for leaks. there are non...i guess...LOL...with the timing? what should it be set at? i took my boost controller out so im running 9psi. STOCK LOL!!! so much slower...so what should i setr the timing at?

cheers,

[jkotsa]

yeah i have the exact same problem i think it is the BOV because i have one that vents to atmosphereand it sometimes stalls. As for the timing not sure? i would check the BOV and if u have a standard one lying around anywhere id like to buy it?regardsJIm

[lingeringsoul]

yeah im adding myself to the mystry idle club as well. It was varying anywhere between 500-1100, had the O2 sensor replaced and it was well for the first month but then it started playing up again. Can't be another dead O2 sensor can it?

[dmr]

try cleaning out the aac valve, it's usually the case: http://www.skylinesaustralia.com/forums/t1...html&hl=aac

[RB20JT]

i cleaned that! ages ago...took i off the other day. still clean as. so not that...i only replaced the afm bout 3 months ago. so thats cool....so im breaking it down to std BOV leaking....or the 02 sensor....or timing...

i know the std bov is leaking..but its plumbed back in..does that make a diff?

[4drftn]

got the same problem... or though i went around and tightened all my FMIC clamps ect. and it ran alot better. as far as your bov goes i have an atmo bov and it ran like crap but after tightening the tension it ran alot better again, as far as O2 sensor ect. i run an aftermarket ecu and my sensor isnt even plugged in..., do you have an aftermarket ecu that controls air ect.?

[RB20JT]

ey nah i got factory ecu. umm...i went round and tightened all the BOV fittings an a few vacuum hoses. but i have yet to double check cooler pipings...but i reckon the car has become a bit laggier!! so might be the fmic hoses...got to check anyways.

cheers

[snappy_]

I have the same problem too but when i installed a remap in my ecu, my car decided to stall when i come to a stop, at most time it does.

I've also got the stock bov on too.

I've upped the idle, but still stalls and varys.

Need help

Cheers

[BAMR33]

Hey guys, I had the same problem. Something to try if you're having idle issues, get long nose pliers and block off the hose the that goes into first air control valve located underneath the intake manifold, It's the device with two hoses coming off it running up to the aac valve, after this is blocked off you can adjust the idle screw on the aac valve until the idle is stable.

[RB20JT]

the hose that goes into the throttle positions sensor? because i only have one hose going into my aac valve???

[BAMR33]

Not sure with rb20's, but rb25's have a valve underneath the plenum with two hoses going up to the aac valve, mine failed and I have just blocked it off, solved the issue.

[RB20JT]

valve underneath the plenum? hmm....interesting....if anyone knows where this and what it is on the RB20det, please let me know as i wanna try this.

cheers

[4drftn]

i took my aac off and gave it a clean just like the link but it didnt help me... same problem. i rang a place and they told me to get a new aac... good luck if i can get one. but then again could be somethin else. i noticed tackin the brown plug off (rb25) it had a steady idle but dunno if it would do anything in the long run.

[RB20JT]

not sure....mine still plays up a lkittle