Hi all I just got a ultra gauge for my 2003 mcs and when I looked at the boost pressure it's providing it's was negative at idle which I assume is normal, but when I rev the engine at all it seems to become more negative. Went from -8 psi at idle to around -12 at 4000 rpm. The car does have a 15 percent pulley as well and have done a bunch of work to it. Is the gauge wrong or is something horribly wrong. Thanks

 

Where on the intake is the gauge connected?
It has to be tapped in "downstream" from the SC.

 

You need to T off the vacuum line on the bottom left corner of intake manifold under the intercooler.

 

It's a obd gauge so no vacuum lines or anything.

 

If you are able to select the MAP sensor, maybe try the 2nd one.

 

You don't suppose it's pulling data from the MAP sensor instead of the TMAP, do you?

Edit: Ha, nd-photo appears to have beaten me to it.

 

Great minds think alike :P

 

It doesn't have the ability to change it but I did notice that when over 3k I do seem to produce 2 - 5psi of boost pretty sure got a major boost leak so wi will try to address that first. Appreciate the input though thank you.

 

Good luck and report back!

 

My OBD Fusion Bluetooth app does the same thing until acceleration (15% SC pulley). Then it spins up quickly to 15psi.

 

Ok so I finally got the new boots and no change. This is going to sound kind of stupid bout could the boost reading coming from a obd port differ from a mechanical gauge. Just because with a 15 percent pulley I don't get more than 11psi at peak boost.