Checking 2JZGTE Sequential System

[wilbo666]

Checking 2JZGTE Sequential System:

Outline:
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.

I've put together this information to hopefully help people to find and fix issues with their sequential turbo system.

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 won't go into how the sequential system works, there are other places that explain that.
e.g. http://www.max-boost.co.uk/max-boost/supra/turbo.htm

This information is based off TSRM (Toyota Service & Repair Manual) HERE and HERE for JZA80 for the most part.

Block Diagram:
The below figure identifies the items to be tested, and shows locations.



VSV for Wastegate Valve:


VSV for Exhaust Gas Control Valve:


VSV for Intake Air Control Valve:


VSV for Exhaust Bypass:


Intake Air Control Valve Actuator:


Exhaust Gas Control Valve Actuator:


Pressure Tank Testing:
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. IACV. If the pressure tank is working a release of pressure when you remove the line should result.



Wastegate Actuator:


Cheers
Wilbo

[wilbo666]

Blow Off Valve Testing:


Exhaust Bypass Actuator:



Advanced Testing Notes:
It is possible to test say the Intake Air Control Valve (IACV) without removing the VSV for the IACV. Below describes how. This same test moethod can be used for the Exhaust Gas Control Valve.

E.g.

• Remove Hose from IACV VSV that comes from the Pressure Tank
• Use a small plastic syring to apply pressure (The IACV should not open with the VSV unpowered)
• Power the IACV and the pressure from the syring shoud cause the IACV Actuator to actuate / move (The system should hold pressure / not leak)
• Remove power from the IACV VSV and the pressure should be vented by the VSV and the actuator should close.

System Still Doesn't Work:
If the sequential turbo system still doesn't work after checking the above items then there are a number of things that might be wrong still

• No Power to VSVs
• No Engine ECU signal to VSVs (Broken wires / plugs / ECU etc)
• Damaged turbos (I.e. rear turbo with no turbine wheel)
• Damaged IACV, EGCV, Wastegate or Bypass Valve
• Large Boost Leak/s
• Incorrect Hose Routing
• Other

Cheers
Wilbo

[big_zop]

You are the man Wilbo, this will definitely come in handy in the future!

Id give you some rep but apparently i have already give you too much.

[1jz68u]

great work....

[ONETEN]

good work dude, fairly irrelevant to me but i can see the worth for clueless 2j owners!!

[PlacentaJuan]

nice work +rep.

took me years to understand how all this crap works.

[Draven]

At least toyota built the engine to encourage people to rip all that crap off and install a single big turbo

[JustenGT8]

Subscribed for reference

[aristoman]

Subscribed for future and rep points added