[aplusmt]

if anyone can help give me an idea about this.
at about 4500 rpm at full throtle my 93 vr-4 with 42000miles and no mods, falls on its face, and pufs out white or white blue smoke (its hard to tell), it has been said that this is a turbo going out.
is there a way to tell for sure or is there some other malfunction causing these problems??

thanks for ANY info

 

[RacerX_GTO]

This is my best guess

White smoke = Radiator coolant burning. If that happens you probably got a blown gasket, and are losing some compression in one or a few of your cylinders. If you got coolant going out your pipe that of course introduces all kinds of nifty problems, starting with the exhaust impeller down to your O2 sensor.

The part about your turbo going out does not seem likely. If your bearings go out, the impeller shaft does not turn and you get that 'glowing red' turbo syndrome at some point. If your impeller blades are all jacked, then your boost would be more like a puff, because the air is not being moved effeciently. Since you say it only occurs at WOT, then it may be boost controller related or wastegate vacume.

Ways to test:
You're gonna have to do a compression check on all your cylinders to rule out a blown head gasket. If that is not the cause, then you can be safe to move on to something else. To test your turbos, you're gonna have to take off the air input hose and with your finger, see how freely they spin. If they don't, or have an unusual amount of resistance, you got a bearing problem. Take a mirror and a flashlight and check to see of your impeller blades are in tact. If it is none of those items I have listed then you move on to your fuel system and timing ad trouble shoot it down to the ECU if you have to.