Rough Idle When Cold

[dori34]

hi guys, been having this on going issue on my R34 RB25DE+T ever since the turbo conversion.

when cold (left overnight for example) i start it the next day and the idle is very rough and lumpy and the car full shakes/rumbles etc but give it 2-5minutes then it will just idle normally.

any idea what causes this and how i can fix it?

i took apart the AAC on the weekend and gave that a clean with TB cleaner but no luck.

however i believe the plug connecting to the AAC wasnt properly connected and it was tuned like that.

when i got the car back i thought the rough idle was caused by o2 sensor not being connected (thats what the tuner also told me) so i connected it up and it still happened.

2 months later, i serviced the car and i plugged it all back in after putting the sparkies in then it idled like sh*t (stage 3 cams like) even when warm so i disconnected the plug to the AAC played around with the idle adjuster screw a bit and manage to get it idling okay but till this day, as mentioned above, it still idles sh*t when cold.

any help much appreciated as it is quiet frustrating not knowing why its doing it.

Cheers

[paulr33]

well you said its happened since the DE+T

when you did the conversion what did you change (list everything, even if you think its irrelevant)

[Moodles2]

Did you put the ECU into base idle mode when doing the rpm adjustments?

[Dose Pipe Sutututu]

using powerFC or aftermarket computer?

add more fuel when the engine is cold int he fuel enrichment vs temperature section

[MBS206]

Sonuds like AAC isn't setup when cold...

Revs should come up above 1000RPM when cold to stop the shaking.

Cold engines don't idle well when they're idling low.

[dori34]

emanage ultimate

apparently the first guy said he tuned it for cold start

which i dont think he did as i found alot of short cuts in the tune since taking it elsewhere.

fmic,

turboback exhaust

spark plugs

oil + oil filter

gtt injectors

33 gtr fuel pump

turbonetics turbo + ext gate

stock manifold

intake pipe

moodles; no i did not. but it never happened previously when it was NA.

so wat im thinking is the tuner tuned it with the AAC disconnected.

i think MBS206 is spot on here. will have to speak to my new tuner to see if it can be fixed easily.