wastegate solenoid ?

[MARINES185]

ok, i think i can explain the function of it as a valve to bleed
boost away from the wastegate. so when the desired boost
level is obtained the computer closes the valve allowing all
boost to go to the waste gate. now the question is in normal
driving such as cruising is the solenoid open or closed?
i was just wondering because i thought that it should be
open but i can't blow air through it. somebody help me out.

 

[scottyb]

First, I want to know how you blew into the solenoid while cruising.

Your theory is actually backward. If the solenoid stays closed, then the actuator would open at it's sping pressure which is ~ 10 lbs. When you are in the throttle, it pulses open to bleed off pressure so that the WG hose system maintains ~10, while the turbo is actually producing ~15. So basically it bleeds off about 5lbs. The "y" connector restrictor is the key for the wastegate solenoid to handle the flow rate and still bleed off 5 lbs in the "almost closed" WG hose assembly.

The ECM does not sense boost. The pulse/bleed amount is programmed and assumes the hose/wastegate system is correct and intact. We crank the rod down a bit so the spring pressure is 12 lbs, the solenoid still bleeds the same amount (~5lbs), now we get 17 actual.

Clear as mud? I know I didn't answer your question. I *believe* that it starts to pulse based on either throttle position, maybe load, maybe a combination of events.