Yet another ISCV issue (2JZ)

[takai]

Right, after fixing what seems to be a never ending stream of idle issues on my 2JZ i finally have warm idle down pat, with it sitting nicely on 800rpm all the time.

Cold idle on the other hand is decidedly not happy. What i have figured out its down to is the ISCV not fully retracting, so i thought that this was an ISCV issue and replaced it with a spare, but to no avail, still not retracting past half way when the engine is turned off.

So i turned my attention to the COR and whether the ECU was getting power after shutdown to keep the COR open and therefore open the ISCV, which i have determined it is, you can audibly hear it opening the ISCV after engine shutdown, but every time it opens it the same amount. Ive tried jumpering the ISCV to permanent power, while leaving the control wires the same, but to no avail, and i have tried jumpering the ECU so its permanently powered, but also it only winds out the ISCV to the same point.

If i manually wind out the ISCV then it will idle up to 2000rpm and gently lower the idle to 800prm as the engine warms up, just the way it should from factory.

I cant figure out what is going wrong. Anyone have some ideas?

[CrUZida]

I've heard rumours of there being a special procedure to get the ecu to control the ISCV properly (eg, after an ecu reset), however not ever having the problem, I've never bothered looking it up.

Do you reset the ecu when you pull the ISCV out and wind it all the way out?

[takai]

Yeah, i reset the ECU as well, although maybe not fully, still would have had one of the B+ as the 2JZ Supra ecu is slightly strangely wired up (according to the wiring diagram you have to pull IGN, ECU and ECU-B to cut power to it).
Maybe ill try pulling power to the entire car next time i reset the ISCV.

[CrUZida]

Perhaps its a faulty ECU ?

[takai]

Could be, but it does everything else perfectly, so i dont see why this is any different, or at least i cant figure out why the ISCV management woudl fail over anything else.