Engine/Transmission (1998.5 - 2002) Iffy waste gate?

[ESwartzer]

I have an issue with moderatly low boost. I can get on a freeway give a little pedal and sometimes get to 30psi boost. When I try to give it more throttle later on the boost is hard to get over 20psi. and I get a howl! I made up a pressure tester with plumbing fittings as per tdr advice,and found a leaking bolt where the horn bolts to the intake manifold. Also found a leak in the wierdest place, a small threaded hole on the back of the intake horn. I fixed both leaks and cant hear air escaping anywhere else. I soap tested all the hoses, and they seem fine. Question would I be able to find an intercooler leak without removing it ? Secondly could an intermittently sticky wastegate be the problem? How would I go about diagnosing a sticking wastegate,and if its the problem can they be repaired or do they need replacing? The turbo itself is OK at least Im pretty sure it is. Any advice will be appreciated!!! Earl

 

[RShipp]

Remove both aftercooler hoses and put a radiator pressure test kit on the intake and exhaust on the aftercooler. That's the way I test mine. Just regulate your shop air down to 50 psi so you don't blow anything. It could be possible that the wastegate it sticking. I had a howl on my 40 when I installed it. I didn't have the room to run the wastegate and wired it shut. I later went and installed a j hook with a turn buckle to keep constant tension on the wastegate. You might have a weak spring in the diaphram head. Excuse to upgrade to a big head wastegate.

 

[ESwartzer]

Ok, I just disconnected the boost elbow from the turbo and plugged the hole with a fitting. Took it for a drive and same thing, OK boost at first then can,t get over twenty psi. What its doing now after I rev the engine, is Im hearing a big whoosh at the airbox. Took it back home and revved it in the driveway and as soon as I release the throttle I can hear the huge sound of air escaping. from the intake box ! Does that sound like a bad wastegate? Can the gate stick open when it gets hot , but be OK when its cold ? I can find no other leaks in the system. HELP!!!

 

[Devan Manis]

I think that often we focus to much on the intake side of things, but remember that for a turbo to make boost you also need the pressure in the exhaust side of things before the turbo. An exhaust leak will cause low boost and low power just as easily as will a leak on the intake side of things. If you spin your compressor does it spin easily? does it have alot of end play ie: hits the housing, oil?