ISCV Cleaning (*May* solve poor/erratic idle)

[Smokey228]

I think i traced those hoses back to where they went and disconnected from the other end...

Also, i'd gladly use gasget goo if paper wasnt available, as its not going to be getting to hot, and its only sealing it from air pressure, which in alot of cases the goo might even do better... The heat can perish dodgy seals sometimes, but i dont think you'll have issues there...

Also, i used some brake cleaner to clean that thing, it didnt do much, i used subaru upper engine cleaner, the motor almost refused to start from compression lock, but eventualy did and seemed to run a bit better, but again, not a whole lot of improvement...

Cheeers,
jaseq

[mikie]

do ICSV need to be heated. ie water running through it, for them to work properly? i have cleaned mine, checked that it opens when the motor starts. but doesn't seem to close when the motor come up to temp, currently no water ruinning through it. any suggestions??

Cheers Mike

[Twinky16v]

good read. i too was surprised alot of you havent heard of subaru cylinder head cleaner. it works a treat and just powers through carbon aswell

apparently its used in subarus service due to their motors being prone to carbon build up?

iv used it in my 4age bigport many times and i have found it to be the best. but 4age idles are never perfect

[Smokey228]

I cant remember what mine had running through it, but there was one into the plenum and from memory maybe 2 going else where...

If it had water running through it, then it would certainly need it to be there, probably for temp or something... But my understanding would be that the computer takes temp from its own sender, then then adjusts the ISCV to reach a target idle speed..?

Cheers,
jase

[Officer Doofy]

Water going through the iscv is more for cold climates to stop them sticking i think. To get to the bottom hoses a nice pair of long nose pliers is needed. I prefer the bent nose variety.

[Gibbon]

I'm surprised none of the gurus here actually know of this but...

Head down to Subaru (Yes, I know, it's a Toyota forum, shut up, and read on)
Go to the spares/servicing section, and buy a few cans of Subaru Upper Engine cleaner.

Now head back home (Or out to some place you can't annoy people)
Unplug the line that goes to the ISCV from your intake piping (So you have a flexible hose going to the ISCV you put shit in!)
Spray for around 1 minute down into this pipe with the upper engine cleaner from Subaru.

I plan on doing this on the weekend - I have a 1jz with low idle issues after it warms up. Problem disappears if I turn the engine off / back on - it resets the idle straight away.

If I'm looking at the right thing - the ISCV on the 1J is the round black cylinder on the inlet manifold at the back of the engine. It has three connections to it - two would appear to be the water connections - the other one is a large pipe that goes off into the head - is that the one to spray the cleaner down?

Cheers

[Z2TT]

Dont Spray cleaner down the pipe, you have to take the valve apart and wipe the gunk off, not sure how it's like on the 1jz but there should be 3 screws on the actual valve that hold it together.

[1JZ~lux]

The 1JZ ISCV uses 2 pins to hold them together. they can't be taken apart or put back together easily. Take the ISCV off the plenum, spray it, wipe what you can off, put it back on but leave the air hose off. Start the car and spray a bit more in the ISCV's air intake. This is what I did with mine (using carbie cleaner) and it made a big difference, no more sticking.

[Gibbon]

(using carbie cleaner) and it made a big difference, no more sticking.

Is WD40 ok to use?

I bought a can of the Subaru engine cleaner - but used it all up when it was suggested not to spray it into the air intake of the ISCV.

Didn't seem to make much difference. And there was no black crap that sprayed from the exhaust - just a cloud of steam (?) that only lasted about 5 seconds.