hollcraft1

What would be the reason why a turbo is not biulding boost? All the vacuum lines are connected and everything else looks ok. Could it be because all I have is a 3" down pipe off of the turbo?

TRBOPWR

Nope, it should still build boost. How do you know it isn't building boost? Not something really easy like a broken guage is it?

sleeper_inc

Broken boost gauge, bad wastegate, seized turbo, majour vacuum leak (boost leak)

Fox90_4cyl

If it was my car I'd check the guage first, and if that isn't the problem take the turbo down and make sure it spins free, then start replacing vacuum lines (not like they are expencive).If its none of the above you might have to invest in a new waste gate

sleeper_inc

Its easy to check the wast gate, take an air compresser and set it to push 15 PSI only and turn it on the hose, if it moves then its fine, if it doesn't move, its blown

turbo2.3stang

If it was the wastegate, then you would have an overboost problem since it's not letting any pressure to be by-passed. Check fora locked up turbo.

TBird232ci

Not true. Wastegates have an internal spring and diaphram. If the diaphram is torn, youll make more than normal boost. If the spring is worn out, youll make very little boost.

Even with the wastegate wide open, youll still make a few PSI.

turbo2.3stang

But he is not making any, so in turn, that would constitute something other than a weak wastegate spring(which would allow minimal boost)

giamanut

Post more info! What do you mean no boost? While driving or while reving in your driveway? See that you are running a straight 3" down pipe this is a valid question. If you are reving in your drive you will never show boost unless you are power braking (no load + no boost)
Really need more info

mg man 75

On my conversion turbo coupe in 89, had the clip come off wastegate. No boost. Just another idea to add.