Originally Posted by
SJM1985
sorry pal i haven't got a spare one. Before you buy a new i would check the small vacuum hose attached to bottom of map sensor from what ive been told the sensors hardly ever break but the air hose becomes frayed and splits at its ends allowing extra air in which confuses the ecu.
Ive checked my bible lol (haynes manual) it says that all three sensors are used to calc turbo boost:
1)air intake- amount (new)
2)Intercooler- oxygen quanity (how warm air is)
3)Map sensor
i personally would check every air hose from air box to inlet manifold for signs of splitting etc.. If the waste gate is to blame then i would of thought that the turbo would not kick in at all with the map sensor plugged in or not. (it would either boost all the time or not at all)
I have heard that this problem can also be caused by block air pipes on the head because it stops the head from decompressing properly so the map sensor thinks that the engine is constantly at its top working pressure those stopping the turbo kicking in by sending all exhaust gases away from the turbo via the waste gate (sumthin like that anyway)
cheers, im sure we are in the right ball park. just had a spin in the car and its deffo getting some boost, though i can hear the turbo at low revs, the car does pick up at around 3000 revs. ie the boost). so it defo leaking boost i think. gona have a play at the weekend. think im gonna strip the exhaust man and turbo and see whats going on. and i will check all pipes again for faults. cheers for your ideas i will report back with my findings.