On my 4x4 cosworth i have no boost, flat out i'm doing about 105!!! The wastegate doesnt seem to be opening, i dont know if its the turbo, actuator or what. The turbo has a little front to back play but not a lot and no movement side to side, uder accleration at about 4000 revs plus when you let off the accelerator it sounds like a dump valve (i gather this is all the gasses going back) Can anyone advise me on what to test, has anyone had this before? Its a 4x4 cosworth running standard everything. Lately its getting me down because when i speak to garages they dont have any equiptment or knowledge of the cosworth engines.
Any help guys would be AMAZING!!
Andy

 

Has the actuator rod slipped off the wastegate ?

 

no its all on ok!

 

take the actuator rod of the turbo and see IF the wastegate is actually working ie moving or has it siezed in the bush or at worse the penny may of fell off!

 

yeah you can move the wastegate lever by hand freely so that seems ok, the penny is still all intact as well

 

the wastegate shouldn't be opening anyway til you hit full boost, if it was open then you'd bypass the exhaust turbine and make no boost.

have you done anything to it?? presumably this has just occured out of the blue?

check that the amal valve clicks when you remove and refit the electrical connector ( whilst the engine is running )

other than that i'd go for a split diaphragm in the actuator

 

one other thing i took the pipe off that comes from the turbo housing and the amount of air coming out of it is very minimal, I think the turbo was given up!!

 

the turbo doesn't spin very fast at idle anyway, so you may not feel much coming out

 

This sounds similar to what I had on my Cos 4X4, my car wouldn't make more than 2 PSI of boost.

If you still have a standard exhaust, it could be the first precatalyst (the one on the downpipe coming from the turbo) that has collapsed/melted partially (could also be the other 2 cats further down the exhaust), just letting thru off-boost exhaust gasses.
When coming on boost the passage is to narrow and blocks the way for more gasses and the smoke returns to the plenum choking the engine.

(at the same time the membrane of the original Bosch dumpvalve was ruptured too, probably the fault of the melted cat, so i had to fit a new
dump valve too)

This cured my problem:

remove the downpipe, cut a little window/flap with the angle grinder in the cat, open it up and remove the material, then shut the window/flap and weld it up.

or you can fit an aftermarket exhaust without cats.

I hope this helps, with me it did

Kind regards