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Last night I was testing out the differences in sequential and TTC. In sequential, I was hitting 20psi in 3rd and holding. In TTC, it would spike 20psi and fall immediately to 16psi to redline. What would cause this difference? The eTTC switch simulates the ECU's signal to open the actuators, so how could there be a difference there? I hope someone has some input. I like driving in TTC, but sequential pulls and boosts a whole lot harder.
 

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I tried ETTC on my '97 "Jewel Green Pearl" Auto Car. In TTC mode, the car would hold a set boost level to 20psi.

Maybe your switch setup or VSV's are bad. Sounds like a VSV is closing and not allowing intake air into the 2nd turbo IACV. Or, it could be the EGCV not staying open... Probably a faulty Pressure tank which is used in ETTC to open the VSV's for TTC mode.

So, now you can check it out by watching the EGCV and IACV actuators. When you switch the ETTC, you should see them opening. If they are not opening, sometimes you can actually hear them popping a bit, then your pressure tank may be bad.

Hope this helps...not sure if all the details and acronyms are totally accurate, however the general concept that with ETTC the VSV's are operated by the pressure tank. So, it's either the VSV's or the pressure tank, or your wiring, or other....
 

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I found out "Jewel Green Pearl" after I made my screen name. I have a 98 brochure, and I figured all the greens were the same. Oh well.


Whenever I flip the switch, the exhaust immediately gets deeper. Maybe my intake actuator is not opening fully? I'll try what you suggested about looking at the actuators as I switch it. I was also considering wiring the actuators open. There should be no doubt about that one.
 

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If you want to change your screen name, just email Dusty...he should be able to help you!!! Then you'd be politically and actually correct.

Also, remember that the pressure tank may become unpressurised when parked....so you may need to drive the car around to get the tank pressurized before you do your visual inspection of the actuators....for an accurate test.

Also, wiring TTC is sometimes difficult to reverse.
 
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