dhays

iTrader: (1)

I've spent hours looking through the vacuum diagrams and all the links that I can find on troubleshooting the boost system. I'm still a bit (OK, more than a bit) confused.

The problem is that I'm getting NO secondary boost. I'm getting good primary boost however. I do know that past 4500rpm the Charge Control Actuator isn't opening. Strangely, after revving the engine past 4500, the Charge Control Actuator does open just for a second as the engine is spooling down again, but it doesn't open at any time with power applied. Not sure why it would open for that second.

Anyway, I removed and tested and swapped the Turbo Control Solenoid Valve, the Charge Relief Solenoid Valve, and the Charge Control Solenoid Valve. In the process I found that my vacuum chamber was holding good vacuum and my pressure chamber was holding pressure. All hoses appeared to be in good shape and in place.

I do have an AVC-R installed. It is possible that I could have screwed that up, although I was using some pretty clear instructions from Dale Clark's site and I plumbed it correctly.

I guess I'm just confused as to how the system works so am having a hard time making the next step. As I understand it, the Charge Control Actuator has vacuum applied below 4500rpm and secondary turbo pressure applied after 4500. When the two pressures from the primary and secondary are equal, then the Charge Control Actuator opens allowing the Secondary turbo to contribute to the boost pressure. It seems to me that the Charge Control Actuator is just not seeing any secondary boost pressure. So either one of the solenoids that switches from supplying vacuum to supplying Secondary Boost Pressure to the Charge Control Actuator is not working (even though it tested fine) or the Secondary Turbo isn't spinning and therefore not producing any boost pressure?

Is it possible that the secondary isn't spinning up? And if so, would this be because the Turbo Control Actuator isn't opening the valve to send exhaust into the second turbo? Is there any way to test if the Turbo Control Actuator is actually opening? Finally, what can cause the Turbo Control Actuator to not open?

Sorry for the long post....

dgeesaman

iTrader: (7)

You've established that your CCA isn't staying open. It's not uncommon for the CCA to develop an internal leak. I'd start by testing it with a Mityvac.

It's pretty unlikely that your secondary isn't spinning.

Did this boost problem exist prior to installing the AVC-R?

Dave