so i installed a defi racer boost/vacuum gauge today...

i used zip ties on the vacuum hose T-fitting and another zip tie where the hose goes into the sending unit.

after a quick drive, i can't seem to read more than 17 or 18 psi boost.
do i have a leak or could it possibly be a bad sending unit?
(i bought the gauge used)

if it's a boost leak, where could it be?
i have <1k miles on this car and everything is stock.

TIA

EDIT: added pic to show where i installed the T-fitting...

 

Do a 2nd or 3rd gear pull to redline.

 

that's basically what i did... only hit about 17 or 18 peak and immediately dropped down

 

That seems a little weird! What altitude are you at?

 

nothing too crazy: ~1100 ft.

i should also note: when it hits peak boost, it doesn't hold peak at all... it drops immediately after hitting peak (despite being WOT).

EDIT: also, i verified that the FPR hose is still attached.

 

i wasn't hitting peak boost until I changed out the fuel pump relay.
then i had another leak, but it was audible balloon screetching air out from my licp coupler to frontmount

 

did you have a bad relay or did you switch to a different one (like from black to blue)?

i haven't checked, but i'd assume mine is blue already since it's a 2012.

 

this may be unrelated, but there have been a few times when i tried to start the car (cold) and it wouldn't start. yes, i gave enough time to let the fuel pump prime... maybe it is a bad relay... i'll definitely look into this tomorrow!

 

When I installed my boost gauge I had the same e exact problem, it was a boost leak.

 

A tester doesn't cost a lot to make.

 

where was your leak at?

 

Im interested as well. Im pretty sure I have a leak somewhere as well I can hear it at 2700-3500 but just when the car is cold. So that makes me think its the uicp and as soon as it warms up the pipe or whatever its leaking expands and stops leaking. I only hit 23 at peak but I'm also at 3500 ft and running cobb stage 1 91 for 2011. I did check my boost with my ap and its exactly at 0 psi when I hear the noise.

 

And yours is gonna be black. The 2011+ have an updated black relay that is different from the 08s evos.

 

just ordered a t-bolt clamp kit (to replace all the worm-gear clamps). if i have a boost leak, hopefully that will eliminate the issue.

 

Mine was caused by using the wrong size T when i tapped the BOV line for the gauge.