Technical GT TURBO MK1 Vacuum hose

[Ronnie25]

Hi
As i almost finished restoring a Gt Turbo from 94
now i'm stuck
No boost from hose to turbo gauge only vacuum
The vacuum hose was a mass on this car
Any idea what it can be causes
The car has a tuned engine and it was standing in a garage for more than a year without starting or driving
now that i started the car cant get any boost
but the BOV works and opens but no boost in hose
and Wastegate wont open because of no boost
Help needed please
I put some drawing and picture of the hose i dont know if they are connected right or wrong
Regards
Anthony

 

[blu73]

well hard to say really... but for there to be no physical boost at all the wastegate on the turbo has to be jammed open. Engine runs, turbo spins, it makes boost - only was it cannot make boost is if its utterly destroyed internally or the wastegate is wide open.

hard to to make any definitive diagnosis from them pictures but one thing strikes me as strange on your little diagram and thats the boost control. I can see in the last 2 pics this is a dawes bleed valve style thing. You should have that going from the turbo compressor side to the boost controller valve and back to the turbo at wastegate side and not at all attached to the pierburg valve. You would leave the electrical connection to the pierburg or the ecu gets upset that its not there but you don't plumb it in. OR, you would remove the boost bleed valve completely and run the vac lines to the pierburg and back to the turbo. So you are using either the dawes bleed valve or the pierburg to control boost, one or the other but not both. I would add also that them dawes bleed valves have a right way and wrong way round so check its orientated correctly as well

 

[bellini]

This is mine it's a gt3 but vacuum pipes should be the same. You should have a vacuum from the wastegate to back side of turbo (bleed valve or pierburg in between), then one from top right hand corner of inlet manifold to the ECU, one from just under to the fuel regulator. On the top right hand side corner of the inlet manifold to the BOV and in car gauge, from the top of the air intake (behind the MAF) should be 2 pipes one goes across the engine to the little black 3 way thing then one goes on the blue from the drivers inner wing and other goes to the into the boost pipe in front of radiator. Hope that helps. ?

 

[bellini]

Also might be worth checking if the actuator opens and closes.