high idle??

[Loomin]

Hey guys. Just got my first rb26 powered vehicle. I'm previously a Subaru guy and my idle on my impreza was about 850-900 rpm.

I just imported a stagea 260rs with an rb26 and the idle is 1400-1500 rpm. Even when it warms up. Is this normal? I tried adjusting it with the set screw on the ITB's but that's as low as it would go. Is idle controlled by the ecu?

Thanks!!

[nimblestix]

Google "setting iacv or aacv. Theres a screw you can adjust in or out to allow more/less air in under idle. It's located on the underside of the intake plenum.

Or also check for vacuum leaks.

She should probably idle around 1k

sent from a galaxy far, far away

[Skym]

Faulty coolant temp sensor, AACV set too high, IACV is sticking or has failed (valve inside is not closing), intake airleak near throttle bodies (stock intake gasket's have blown which is common on RB20, RB25, RB26 engines).

AACV = Auxiliary Air Control Valve.

AACV controls idle when engine is hot and adjust's idle rpm roughly 350rpm higher when aircon, light's, etc are on (auxiliaries), when turning steering wheel.

IACV = Idle Air Control Valve.

IACV provides air on top of what AACV provides when engine is warming up (engine runs richer when warming up) and slowly closes as engine runs leaner. Valve movement inside IACV is activated by heat from engine, voltage. Once IACV is closed the AACV controls idle rpm. But IACV can stick open due to sludge buildup from oil in blowby gas over time (km travelled), front turbo oil seal failure, thus causing higher than normal idle.

On R32, to set AACV you need to set engine ECU into idle adjustment mode (via consult or manual way, usually mentioned in engine manual, which involves turning diagnostic screw on side of R32 ECU all the way to left on ECU. Also note run position before turning screw, amount of turns from run position). Then unplug AACV plug (so ECU doesn't adjust idle rpm) and adjust AACV screw to correct idle rpm. Then plug AACV plug back in and see if idle rpm says the same. If idle rpm doesn't stay the same, repeat procedure until it does (easier with Consult that displays accurate rpm). Then return ECU diagnostic screw to run position (be aware that turning diagnostic screw to right can raise idle rpm 250rpm at a time). In diagnostic mode a stock ECU should flash sensor codes on dash (cat overheat light / engine check light).

R33 ECU (similar engine ECU as installed on a Stagea) should be similar to R32 ECU, but it's alot easier, more accurate to do the above via using Consult.

[Loomin]

Thanks for the replies guys!! I'll hopefully get this sorted this weekend. Also just wanted to add that with the cold weather we've been getting this week, thebidke now seems too low for the first 30 seconds or so. I have to keep my foot slightly on the gas or it sputters and stalls.... any ideas?

[Skym]

Check that TPS (Throttle Position Sensor) is on idle contact. When TPS is on idle contact, engine ECU kicks up rpm to stop engine stalling. Sometimes TPS has failed and needs replacing.

Also intake airleak, faulty or dirty MAF could be the others.