boost problem
 

Hey guys I have a boost problem with my t-76 turbo. When its cold like when I first start the car it will boost to 10psi with no problem but after it warms up it will only boost like 5-7 psi and sputters. What may be the problem?

Sounds like the tune or something electronic is acting up once it gets hot. The turbo spins freely?

sounds like the turbo is spinning freely. i think its the tune also but why would it work when its cold and not when it warms up?

Could be a short or bad wire in the harness. When engine bay temps come up this is when this could be really noticeable as the conductivity of the wire is greatly affected by heat. Especially if it is around the turbo or just above the down pipe and not protected very well. Is it a new tune in the car and if not has it done this before?

You shouldn't be boosting the car when its cold, but since you already have been and discovered the boost differences between a warm and cold engine.... Has the car been professionally tuned? Or was some random map put on the car? Has the car ever run correctly with this setup? Does it have a wideband O2 sensor hooked up and being logged? What engine management system is being run? Is the ECU seeing the correct air and water temps?

Assuming the car used to run correctly, and that everything map wise is set correctly, sometimes ignition coils will work when cold and not when hot, so that could be another possibility.

Another possibility is that the car is not tuned, or tuned incorrectly, and when it's cold the fuel enrichment settings are adding enough fuel to keep the engine happy, then as soon as it warms up some, it starts pulling the fuel (like normal) and it's now running much too lean. (not normal and not good....boom!) I'm leaning towards this explanation since you suspect the tune as well, and you would know if the car was tuned or not.... do tell