Remove power from the IACV VSV and the pressure should be vented by the VSV and the actuator should close.Power the IACV and the pressure from the syringe should cause the IACV Actuator to actuate / move (The system should hold pressure / not leak).Use a small plastic syringe to apply pressure (The IACV should not open with the VSV unpowered).Remove Hose from IACV VSV that comes from the Pressure Tank.This same test method can be used for the Exhaust Gas Control Valve. It is possible to test say the Intake Air Control Valve (IACV) without removing the VSV for the IACV. If the pressure tank is working a release of pressure when you remove the line should result. Note this can also be tested in a different fashion by achieving boost, and then pulling a boost line that goes to a VSV off, e.g. The below figure identifies the items to be tested, and shows locations. This information is based off TSRM (Toyota Service & Repair Manual) and for JZA80 for the most part. Reasons Why Our Sequential Turbo Kits Work So Well A lot more cool air enters the cylinders, because the dual staged compressors work together within their. I won't go into how the sequential system works, there are other places that explain that. This guide details how to test the VSVs and the Actuators for the Sequential turbo system, a failure of which is usually the cause for low boost / sequential system malfunction. I've put together this information to hopefully help people to find and fix issues with their sequential turbo system. There are also sequential twin turbo systems, which run on one small turbo at low engine speeds and switch to two parallel turbos at a predetermined engine. I feel that the operation of the 2JZGTE Sequential Turbo system isn't fully understood by many, and when the system malfunctions many people have issues diagnosing the problem. If you've found my work helpful and would like to donate a beer! PayPal.Me/wilbo666wiring

This page details the Toyota 2JZ-GTE engines sequential turbo system.

Sequential turbos