4AGE Specific Info
Manual VVT Control
!!!WARNING!!! The information contained below is from my own personal experience in trying this. If you shoose to follow it you try it at your own risk, although may other people have also done this modification with success as well. I also sugest reading all this section and understand it before you start.
How VVT Works : VVT (Variable Valve Timing) is simple really ... For every day road usage the car runs like any other, but planting your right foot when the car is within given perameters will cause the ECU to earth pin 16 on Plug M (for the auto box model). Once this happens the VVT solenoid is switched on and oil flows down a galley to the intake cam which fills up and retards itself up to 15 degrees. Simple aye.
Modifying VVT : The easiest way I have found since searching the net is to install a manual switch to earth so you can control when the VVT is on or off. To do this just cut the wire that comes off the VVT pin on the ECU (leave yourself at least 6 to 10" if pos) and join it to one pole of a 2-way switch. Connect the other half of the wire to the common pole (normally middle one). Finally join a wire to a good earth and connect it to the third and final pole. I have taken this one step further and installed a switched light as well so I can see when it is on or off. CLICK ME for a wiring diagram
How The Switch Works : In a two-position switch one position is now factory in that it is still controlled by the ECU. Simply flick the switch to the other position and VVT is on wether the ECU wants it or not. The ECU will still turn itself on and off as it meets requirements but nothing will happen as the signal is going no where :D
Conclusion : Apart from an awesomely rough idle when manually switched on and a little more gas consumption the only thing I can fore warn you about is as follows. Make sure you use a good oil and change it regularly. The VVT oil galleries are small and can block easily. When this happens your inlet VVT wheel will become noisey and sound like a diesel when it turns on. This is a common fault (just ring any wrecker) as people always want inlet wheels.
4age 20V Airflow and Throttle Sensor Setup
The information below was pulled directly from a 4age-20v workshop repair manual and are usefull when setting up an engine for the first time and trying to diagnose any problems.
THA (Pin 7) to E2 (Pin 3 or 5) Restistance
@ 0 Degrees C = 6K Ohm
@ 20 Degrees C = 2K Ohm
@ 60 Degrees C = 500 Ohm
@ 100 Degrees C = 100 Ohm
@ Shut : VTA (Pin 2) to E2 (Pin 4) = 0.3 to 6.3K Ohm
@ 0.8ml Open : IDL (Pin 3) to E2 (Pin 2) = Continuity
@ 1.0ml Open : IDL (Pin 3) to E2 (Pin 2) = No Continuity
@ Full Open : VTA (Pin 2) to E2 (Pin 4) = 8K Ohm to 11.5K Ohm
@ Full Open : VC (Pin 1) to E2 (Pin 4) = 3.5K Ohm to 6.5K Ohm
ECU Error Codes
Reading Error Codes : Quite simply put when "E1" (earth) & "TE1" are shorted at the ECU the dash warning light "W" will flash on and off at a given rate. Even though I dont remember the exact time delays it will be somethign like ... flash, pause, flash, pause, pause. This example would be error code 1,1 or 11. Any other flashes after the double pause is done will mean you have multiple error codes.