intermittent smoke from exhaust while idleing?

[nurevem1]

I have a Ka-T 97 240sx. It currently does run rich (550cc injectors), timing is retarded 3 degrees, egr is blocked off and no cat/downstream 02 sensor. Sometimes while im sitting idling around 900rpms there is a blueish smoke from the exhaust but only for about 15-30 seconds then goes away. This doesnt happen all the time and also does it right before the turbo timer turns off the car sometimes..WTF if it were piston rings or valve seals i would think it would smoke all the time.. any ideas? could it just be fueL?(even though i thought blue smoke was from oil) Turbo seal maybe?

[Sileighty_85]

Probably Valve seals

Thats normal for KA's as well

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my turbo smoked every once in a while at idle. then i changed it oout and the smoking was gone. could be the seals on the turbo

[Purestock240]

same problem, but single cam, would compression test not be lower? im 165 all across

[nurevem1]

i would think you might see a little be of a difference in compression if it was the valve seals. Think about it, if oil is getting through air would most definately get through. i will have to do a compression test just to do one see what its at. im thinking of driving it around till summer and park it rip the head off and have it machined and have new parts installed. Would still like to figure out what it is before i do that though cause if i have to rip the bottom end off after already having the top end iff im gonna be pissed.