1JZ IACV problems

jake8790

Life's too short for N/A
Dec 18, 2011
395
0
0
Oregon
My 1JZ IACV will not open before a cold start. I've tried two IACV's with the same result. I can open the IACV on the bench by jumping the pins. When I put it back in the car, the ECU lets it idle down as it should while it warms up. Until the next cold start when the valve is still closed. The IACV has power to both center pins. The main relay stays on for a couple seconds after turning the key off as it should. The TPS is new and set correctly. The coolant temp sensor is new. The ECU has new caps. The only code is 42, the speed sensor is not hooked up. If anyone knows anything else I can try it would be greatly appreciated.
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
0
Fullerton,CA
The iac should be in the very most open position when started. The relay stays on for a couple seconds after engine shut down to pull the valve fully open and reset it's position. When it reaches full position you will hear the little clicking noise from it.
 

jake8790

Life's too short for N/A
Dec 18, 2011
395
0
0
Oregon
I figured out the problem. I tested power at the iacv and found it was on switched ignition power, not main relay power like it should be. I still don't know where I went wrong with the wiring, so I ran new wires to main relay power from the fusebox. So nice to have idle control!