So, I need a new TPS but I have it adjusted in spec at idle. Using the PowerFC to check that. The car idles good, but my problem now is that whenever I touch the throttle the car goes lean and tries to stall. I have a wideband hooked up so I can see it go way lean and try to stall. I have to hit throttle fast to get past the lean area. What would cause this? I think I have the vacuum leaks taken care of. There is only one leak I can find where the backplate mates with the compressor housing on the turbo. Seems to be somewhat common from what I have read. Don't know if this could cause the problems anyway. Any thoughts will be appreciated.

 

So how is your PowerFC tuned in the low to high vacuum areas of the map? Those areas would correspond to partial throttle.

A leak between the compressor cover and backplate is pretty significant. It'll cause a boost leak similar to a loose intercooler coupler. You could get by with a thin layer of RTV along the edge of the backplate, but it'll mean removing the turbo.

 

So remove the backplate and apply rtv to the mating surface? Won't the turbo get too hot for any RTV to hold up in there? I have a my log attached in the powerfc section, but I can attach it here too or send it to you in a pm if it would be easier for you.

 

induction side doesnt get as hot as you think. use copper rtv if your worried about the heat....

 

I am going to go ahead and pull the turbo and put some RTV on the backplate and reinstall. It doesn't seem like this vacuum leak could be my problem though. Wouldn't the vacuum leak cause a bad idle too. My idle is good, it just tries to die when I give it throttle.

 

depending on how bad the air leak is depends on how it will run at certain rpm's. i am having the same problem with my turbo leaking air from the compressor side but i cant fix it until i get a rebuild kit for it. i think that the turbo internals are so bad on my car that the exhaust is leaking through the shaft housing into my intake. it leaks oil and has about 3/8" of shaft play.

if you have any shaft play, i would rebuild the turbo internals while you have it off of the car. might as well get the whole thing sealed up properly to eliminate any possibilities of the turbo being the problem.

HERE IS AN EASY WAY TO DETECT VACUUM LEAK:

start the car and get it to normal operating temp and let it idle. get yourself a spray bottle full of water or use brake cleaner and spray the engine at all sealed components such as vacuum lines, injector o-rings, lower intake manifold to block, upper intake manifold to lower intake manifold, upper intake manifold the throttle body, all intake ducting, compressor side of turbo, etc. and so on. this is a for sure way to find your leak.

 

Currently I am testing for leaks using an air compressor and an adapter on the intake. Then I am spraying everything with sudsy water. I do have a pretty significant leak on the back of the turbo. Bad thing is the turbo is new. It is basically a BNR stage 4, but not done by BNR. So no rebuild in store for me. Just fix this leak and then move on. New TPS will be installed Friday as well as the repair of the leak. Just trying to make sure nothing else could be causing the problem. I can't think of anything other than vacuum and TPS, but it seems weird to have a good idle and immediately stall when a little throttle is applied. A greater amount of throttle and it will rev just fine, but I lose quite a bit of power when I actually try to move.