I have a Evo x arm digital boost gauge I don’t read negatives idk if this is how these gauges are or something Is wrong also my sensor i believe its tapped into the blow off I read 20ish on idle and when I drive the gauge dips to lower number and when I’m on it goes to 0 idk if this is what I should be reading or some is wrong any advice or someone that’s seems this let me know pls.
I have a leak on my downpipe not sure if this plays into this?

 

Duplicating my answer from where you asked the same question in a different thread here.

20 what? I will assume you are talking -20 in-hg which would be normal. the engine is pulling a vacuum on the intake manifold at idle and until the turbo is creating enough pressure to cancel out the vacuum. Then boost pressure(psi) is just the positive pressure being created.

0 with the engine off is also correct as there is no vacuum or positive pressure with nothing moving.

 

Correct now what about as I’m driving numbers should drop and when I’m on the throttle I only see maybe positive 2 o4 at most is this normal?

 

As you are driving and building boost, the gauge should read positive PSI; the exact number you should be is based on your tune so I can't tell you the right number. Factory is like 17-20psi so 2-4 is very low. This sounds like a large boost leak to me, possibly a disconnected wastegate but that something else to check.

Do you have any codes?

 

Ok I have a hole on my down pipe that I recently found. I only get a code for lean and I believe it’s because of this leak from downpipe. But as far as boost leak I did a smoke test from intake and only found leak at the connection from turbo pipe gasket but I fixed that already no other leaks besides the downpipe

 

I don't think the downpipe leak will cause what you are seeing with the boost. I would check all the vacuum lines are run correctly at this point.
Is this a factory setup car or is it modified?

 

just reading your first post on this; it sounds normal and depending on engine loads you will jave numbers between -20 and 0 until you make boost.

not going above 0 would mean you probably have a vacuum gauge not a boost gauge