I recently purchased a rather cheap mechanical boost gauge to get me started (first turbocharged car), and I think I may have tapped the wrong vacuum line. Out on my test drive post-install I idled at -20 psi, spiked around 4 psi, and would cruise around -20 psi. Anytime I applied throttle I would hit 0 but return to -20 at steady throttle. I still have a filter to install but I don't think that's causing this issue. Is the location I tapped a bad call because of the two one way valves up-line? I always see people tap the FpR but due to fitting availability locally I had to tap the line next to it. It is a mechanical Bosch boost gauge. The brass T in the picture is where I tapped.
42.3 KB Views: 655