hey Guys,

I just got this '96 GMC k2500 about 3 weeks ago now. It's had a horrible lack of power, so I decided to pull the IAT sensor out and put a fitting in for boost pressure, found out i've got 0 boost. I've actually got a decent vacuum (No gauge for vac, just feeling it on my finger)

The waste gate actuator is always "down", I can move it up, and even zip tied it up to test it, and I still put out vacuum after the turbo.

Any ideas?

Do you have vacuum at the waste gate actuator?
If so, and you can move the actuator while truck is
running, the actuator is bad. Working back from the
actuator, there is a waste gate solenoid, keep going
back and you'll get to the vacuum pump.
If you have an "F" engine, (8th digit in VIN) search
"turbomaster", you can make one pretty easily, and get
rid of the vacuum system entirely

You missed the point of that. I'm running it zip tied up. I have no vacuum at it. I'm going to be installing tm once the turbo is actually working. No point in making one if I'm just gonna be replacing the turbo.

With it ziptied in the closed position, I still get 0 boost.

It could be a seized turbo. Verify the amount of vacuum available from the pump and that the vacuum solenoid is operating correctly first.

Jake

Zip tie has to be really strong/tight, not much open will
lose boost pressure.
Does the turbo spin freely?

Zip tie has to be really strong/tight, not much open will
lose boost pressure.
Does the turbo spin freely?

I can hold it up with my finger, there's like no force on it. If I let go of it it just glides back down in around 3-4 seconds. That's with my fiance revving the engine or at idle.

To everyone else here, I'm not interested in fixing the vacuum system, I will be removing it and going with a turbo master once I can get some darn boost pressure instead of vacuum in the intake LOL.

Edit:
No shaft play at all, really surprised me given the age. Spins perfectly.

It does make the normal whine sound when revving with the intake box off as well.

Going to go out today and toy with it some more today, will update with any findings.

it's seriosly

No boost without load on the engine. Revving it in the driveway won't give boost. Careful if you zip tye the waste-gate shut and work it hard.

Revving it in the driveway should at least lower the vacuum, not increase it.

And I'm not, I'm driving it around and watching the gauge.

Does anyone have any ideas? I did confirm that my vac pump is shot earlier, but that didn't really matter to begin with. I'm thinking I'm just going to do the turbo master mod and see if I don't make any ground with that. Then move towards disassembly, I'm beginning to think a broken internal linkage to the waste gate? Not sure on these turbo's but I've heard of it happening on other engines. If anyone has more info on that, I would REALLY appreciate it.