fasterbbc

I bypassed the vacuum canister and no change.

RJ_RS_SS_350

If I understand correctly, when you are boosting, then let off the throttle, the vacuum created by closing the throttle opens the bypass valve, diverting some of the incoming air. If the bypass valve is mechanically stuck open, I don't think pinching the vacuum line would have any effect.

When you are boosting, boost pressure is causing the diaphragm to push the wastegate open. If the wastegate is mechanically stuck open, anything you do to the line will probably have no effect.

Can you push the wastegate actuator rod, or is it already at the end of it's travel? On my k04 it takes quite a bit of force to move it. It's hard to imagine the wastegate being stuck open when there is so much spring pressure trying to close it. So I would guess that it is more likely got to do with the bypass valve or solenoid, or the turbo itself.

A shop with an expensive scan tool(tech2 or better?) should be able to test the solenoid. You can get the solenoid for $40-50(links here: https://www.chevyhhr.net/forums/ss-s...e4/#post797763)

If you have one of the Forge bypass valves, I think I read they need to be greased? And there are different springs that go in it depending on whether you are tuned or not. I think too stiff a spring will keep the valve open.

But you don't have the stock k04 turbo, so I don't know if any of this applies.

fasterbbc

I have verified with pressure applied to the waste gate actuator that it moves freely. I have also applied pressure to the inlet of the turbo and the system holds 25psi with out issue.

Also scanned the computer with a Snapon Solstice and found that both the BPV and WG solenoids are being sent power. (verified they function as well) But the interesting part is the data showed 27 psi boost at idle. However the gauge shows 18-20 inches of vacuum. So are there 2 different boost sensors? thinking the ecu thinks its getting boost and possibly in a limp mode relative to boost. thoughts?

RJ_RS_SS_350

Hmmmm..... I wonder if some of the lines are on the wrong ports? I know that you know that there is no boost at idle. So if the ECM is getting bad information, it may be because the lines are crossed? I just figured out that this is a k04, upgraded.

celblazer

Yes there are two boost sensors one in the upper and one in the lower charge pipe. Possibly a wiring issue or bad sensor or wrong sensor. I see you didn't swap them. Possible one set is 2 bar(stock) the other is 3 bar(GM performance upgrade kit). It would skew the readings if the wrong set is in there.

fasterbbc

using the stock sensors GM installed.

celblazer

They were stock on the old motor also? No tune then on the car or a tune matched to 2 bar sensors? Point is compare the sensors, they will only work with a matched tune.

fasterbbc

I don't understand what you are say.

I have not changed the ecu or the sensors from stock.

celblazer

That's what I was asking.

RJ_RS_SS_350

The routing for the Boost control solenoid is pretty much impossible to get wrong, but the routing for the bypass solenoid would be easy to mix up.

Here is a pic from firemangeorge that shows the correct routing. I don't know what the effect of misrouting would be, but it's free to look.

https://www.chevyhhr.net/forums/hhr-...69/#post789297