Overboost hard
 

Hey, im pretty new to the turbo stuff and i am encountering an overboost problem.

-When i start the car, it sometimes have an high idle (2500 ish) and stays like that.
-My internal wastegate opens at 14 psi which is normal, actuator is not stuck.
-The spark plugs are due but there is no misfires
-My afr does not read and i need to change the sond.
-At idle my boost gauge reads -20 psi which i was said to be normal
-Throttle cable is fine and does not let the tb a bit open.

Thinking about doing a smoke leak test but I dont have one.
The overboost happened 1 days before being constant. I stopped the car and it stopped.

A lil help would be helpful,
idk how to pull the logs, i have a basic ms3

Let's pretend we don't really know what you're talking about and that you have not explained it very well.

Now give us all of the details and don't leave anything out.

We don't even know what year car we're talking about.

So i have a 2000 miata with the bp4w at around 250hp on 91octane
The problem im having is overboost. Its like hitting a brickwall.
It happens at 4500rpm and goes back to 4000rpm and back to 4500.
The spooling sound is more intense and louder than it used to.

My turbo is a garrett gt2971r with stock wastegate actuator with the 14psi spring. The wastegate isnt stuck.

As for the parts:
The electronic part: i have coil-on plugs with NGK R5671A-7 and they ran well. There is no misfires.
The fuel part: I have an aem pump rated for 340LPH with bosch 640cc ish so i dont think this is the issue.
The ecu is a basic ms3
My electronic boost controller is free of debris and isnt clogged.
My afr gauge stopped working as it is always stuck on 14.7 and stopped 5-10 minutes before the overboost first occured

Next week i will test for vacuum leaks and replace my bad afr sensor.

The problem i suspect is either a vaccum leak, the afr sensor that causes the overboost of somewhat my ebc.

I'm confused as to why you don't think the first step is getting a working wbo2, because that's your first step.

Especially if you have incorporate AFR active.