Alright guys heres the deal. I installed an Autometer mech. boost gauge a few days ago and the needle seems to work. Only problem is in idle, needle sits around -21 vacuum and going through hte gears boost peaks at 5-6psi according to the needle.

Now, I know I am running more boost than that (totally stock) at least 11.5psi-13.7 psi from what I've read around here so whats the deal?

I have a feeling it could be of some possible "modifications" I've made;

1. I used a 1/4" by 1/4" by 1/4" adaptor to tap the BPV line.

2. The 1/4" by..... adaptor is a "Y" not "T" fitting that I used.
-I did this because the BPV's line did not secure on the T supplied due to
its 1/8" measurement all around (aka: vacuum line bigger than T fitting).

3. I did not seal the line's connection to the gauge via teflon tape/sealant/etc.

Would anyone be willing to help diagnose/fix the problem with me? willing to drive to your location if necessary, preferably around fremont.

 

I'm not sure but my guess is that its not reading right because you used a Y adaptor? I always see people use a T not a Y for boost gauges. I think because you are using a Y there is extra pressure entering the line going to the boost gauge causing it to read lower. Whereas if you used a T the pressure would be going from the bov to the manifold (through the bov line) and the boost gauge line T'd into the bov line will read that vacuume.

I would get a different T fitting that matches up to the inner diameter of the bov line.

Also you should use 3 small hose clamps on the T to make sure there are no leaks.

 

try to use a Cobb AP to get a live read and compare it to the guage

 

Yeah, thats my next plan of attack. On another note though, does the OEM boost gauge kit come with a T that has a larger diameter at the BPV's ends? Because otherwise how do others fit both 1/8" T ends onto that vacuum line?

 

alright fixed it! read ~12PSI in 3rd (forgot RPM's). Got it grounded on bracket and tapped into cig. lighter power (red wire).
Last question! haha
The gauge is supposed to be lit whenever my key is set to ACC. or ON right? kuz i figured it would only light up when headlights go on (like the ring around the lighter).

 

If you want the gauge to only come on when your headlights are on then tap the + into your parking light wire. Thats where I have the illumination wires for my gauges tapped into and it works fine.

 

thanks stg2lgcy00, awesome advice