Just got my 91 tt 300zx but not sure if the turbo is working or not. Gauge is from -14 to 0 to +14. When i drive, it only goes up to 0 and stays there even when I'm goin 95mph. Anyone know what's the problem of the turbo and why the gauge is not going past 0. thanks

I'd say boost leak. Check all seals between the turbo and manifold and all your vac lines from the plenum. Even if you get under the hood, revving it full throttle (backing it off before hitting redline of course) and see if you can hear any hissing. The better way to do it would be to get it on a dyno, put a load on the engine and run your hands past all the seals to see if you can feel any air coming out.

If they all appear to be alright then your wastegates may be malfunctioning.

Cheers.
-Mike

i would buy an aftermarket boost gauge because the stock boost gauge doesn't really always give good readings. if still nothing, it could be your seals or wastegates.

-Jared

Not to assume anything but the boost is not a factor of speed, you can go 95 but if you are on the highway in 5th gear it will read vacumm.

Does the gage not go past 0 even under full throttle acceleration in say 2nd or 3rd gear when going to redline?

i hope your turbos are working! but anyways you should be able to feel the power of the turbos kicking in. is your check engine light on if so you might be running on safety boost

I forgot to mention, it's an automatic, and the check engine light is not on.