i have a 98 suburban that loses boost, i have great vacuum and have replaced that waste gate silinoid.... could the turbo be bad? if so anyone have a good used gm8 for sale or a way to fix....it has pmd relocater with #9 and also has high flow crossover and 3in down pipe and 4in straight pipe any help would be great....Thanks

 

have you checked all the lines for leaks. does the wastegate actually move or is stuck. is the vaccum you have within spec. turbos dont just stop making boost unless it has catastrophic damage

 

not sure if its spec but it sucks the waste gate shut with no problem and i cant open it when running.... so i wired it shut and does the same, out of the hole hard then just falls on its face with alot of black smoke... it will drive with little smoke if you go easy the harder you push it the more smoke you get... i noticed the clamp from the turbo to the down pipe was lose i tryed to tighten but it is stripped, getting a new one....

 

clamp from downpipe to turbo wont affect how much boost you make. any codes?

 

no codes...

 

check for restrictions in the intake and make sure all the clamps and connections are secure so that air has to go into the engine.

 

X2 on woodys statement. Can you move the wastegate actuator back and forth without any binding whatsoever whith the engine off? When a turbo goes you will know it. How are the lines to the wastgate solenoid, and from the solenoid to the actuator? You need to get a vac gauge to properly diagnose it, or a boost gauge better yet. So start at the vac pump. It has to be something with the controlling mechanism to your turbo.

 

can the actuator go bad? when i wire it shut it does the same should i look at a manual waste gate... will check it over the connection when i get a chance....thanks

 

If you wire the wastegate shut and still don't produce any boost, putting a turbomaster on wouldn't do anything. Wiring a wastegate shut is the same thing as adjusting the spring tension too high on a turbomaster and not allowing the pressure to blow off at that critical point. It's simply a test to see what comes next for checking. Getting rid of the vacuume pump is not a bad idea unless you have an S vin then it's a little more involved. I would check your crossover connections at the manifolds. I have seen one that wasn't sealing and couldn't produce enough boost. Not trying to be an a$$, but you have it wired toward the front of the truck right? Looking at the arm it would be counter-clockwise fully closed. If your impeller is spinning, I'm sure the turbo is fine. The last thing would be a non sealing wastegate.

 

so i brought it to my house so this will be easier, it was at my other house about 20 miles away. i think i mit have got it, the rubber boat going from the turbo to the intake seemed alittle crappy.... i didnt have one but i had a rubber hose that fit over the old one i tighten it up and seem to be better but not 100%... hope a new one will fix.....thanks