Desperately need a working ISCV for a 1j!

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
After calling 5 different Jap wreckers with no luck I figured I'd ask you guys. It's a 1jzgte from a Chaser it has the sealed Idle Speed Control Valve unit (not the one you can take apart and clean thoroughly) ...I need to find one before high idle takes a toll on my auto. It has the typical symptoms of an ISCV with the pin stuck - Starts fine and idles fine cold, once it warms up the idle creeps up sitting at 1500rpm in Drive and 2000rpm in Park.

So, in a nutshell, I need a working Idle Speed Control Valve. If someone could point me in the right direction or even sell me one I would be very grateful!

This is what I'm after:

 

te72

Classifieds Moderator
Staff member
Mar 26, 2006
6,610
7
38
41
WHYoming
Could you back out the throttle screw a bit?

p1605825_1.jpg


Talking about the set screw inside the nut to the left of the upper left nut on the throttlebody... hope that made sense. :)
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
Wouldn't that affect the idle when cold as well? it's fine when it's cold.......I suppose it would be a good temporary solution.
Thanks for the tip, I'll check it out tomorrow :)

Would still rather find a replacement ISCV or possibly adapt another one to the throttlebody??
 

mkiiichip

New Member
Sep 10, 2007
1,434
0
0
41
WI
te72;1605825 said:
Could you back out the throttle screw a bit?

Talking about the set screw inside the nut to the left of the upper left nut on the throttlebody... hope that made sense. :)


Will you quit recommending that!? The OP is obviously trying to repair the car the correct way.

shoo_itt, Yes if you mess with that screw it will throw off the factory settings.
 
Last edited:

zoppii

Pro Lurker
May 21, 2007
98
0
0
Palm Harbor
You might want to try and take if off completely and clean it out real good with brake cleaner (including the valve in the manifold) then hook it backup again and see if that doesn't fix it. I had the same issue and just cleaning it out real good did the trick. It's been fine for two years now.
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
I tried cleaning out he ISCV itself with throttlebody cleaner but because its a sealed unit I couldn't get right into it. How do you get the valve in the manifold out?
The thing is, I had this EXACT same problem, with my last car and replaced the ISCV and Throttle Position Sensor and it was perfect after that, it started fine and maintained a good steady idle.
But, RockPaperSwoRD said he has a spare one so we'll see what happens with that.
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
OneJArpus;1606162 said:
is the iscv suppose to suck in air at idle?

Then it closes in boost correct?
It's a motorised valve which goes in or out depending on the car's temperature. When the car's cold it's all the way open to let as much air in as possible to maintain a steady idle. A working ISCV would close up as the car warms up to keep the rpm where it should be. It doesn't have anything to do with boost. - That's how I understand it, anyway.

@ kamikazemkiii: How much shipped to Sydney, Australia? and do you have a pic? BTW, love your sig, Hotrod's awesome!
 

te72

Classifieds Moderator
Staff member
Mar 26, 2006
6,610
7
38
41
WHYoming
mkiiichip;1605867 said:
Will you quit recommending that!? The OP is obviously trying to repair the car the correct way.

shoo_itt, Yes if you mess with that screw it will throw off the factory settings.

If you weren't meant to be able to do this, Toyota would have sealed it off, similar to what they did for the 7m, no? I'm just recommending what might get him through the day, give me a good reason it's a bad idea, back up your theory on why my idea doesn't work.

Oh... I believe I might be leaking a bit of boost out because my ISCV doesn't work well and I messed things up with the screw. Darn, I'm only making 11-12 psi without a boost controller. I must be a horrible Supra owner...
 

mkiiichip

New Member
Sep 10, 2007
1,434
0
0
41
WI
te72;1606295 said:
If you weren't meant to be able to do this, Toyota would have sealed it off, similar to what they did for the 7m, no? I'm just recommending what might get him through the day, give me a good reason it's a bad idea, back up your theory on why my idea doesn't work.

Oh... I believe I might be leaking a bit of boost out because my ISCV doesn't work well and I messed things up with the screw. Darn, I'm only making 11-12 psi without a boost controller. I must be a horrible Supra owner...

Alright, so in the case of this thread. If the OP turned down the idle, while warm to an acceptable range. What do you think that would do to his cold start idle?
Why dont you back up your recommendation? Oh wait, you did it to your car, and you make 12 psi without a boost controller, so it must be ok, right?
Any hack job mechanic, can cover up an issue, I just wish you'd stop trying to get everyone with an idle issue to f'up their throttle adjustment.
 

te72

Classifieds Moderator
Staff member
Mar 26, 2006
6,610
7
38
41
WHYoming
I would imagine he'd have to adjust it to find a happy medium. My car idles right around 900rpm, hot or cold. Perhaps my ISCV is letting a little air in at idle, I dunno, but mine isn't a permanent fixture either. I'll stop recommending the idea when it stops working for me. :)

However, you and I seem to be the only two arguing at all about this issue. Have you read elsewhere on the forum about this issue? I know it's fairly common on 1j's, but I don't wanna start a feud over something relatively trivial. Perhaps we should take this to the engine SME on here? I have no problem being proven wrong considering it isn't giving me any issues, but if it *might* be causing harm somehow, I'd honestly rather know for sure, you know?
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
Yeah, just stop arguing lol.
Anyway, RockPaperSwoRD's selling me an ISCV, if it fixes the problem, this thread will be over....if not, there'll be much more troubleshooting to follow!
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
UPDATE: The ISCV that RockPaperSwoRD sold me didn't solve the problem. Looks like, when the 1j was put into the Volvo they bypassed the Valve, much like many other things on the car... So now I'm out of ideas 'cos I was so sure that was the problem!
 

te72

Classifieds Moderator
Staff member
Mar 26, 2006
6,610
7
38
41
WHYoming
Did you give my original suggestion a try? I know you can bypass them with a standalone, but never looked into *how* to do that, at least not yet. ;)
 

shoo_itt

New Member
Aug 13, 2010
25
0
0
Sydney
I'll give it a go but I don't really want to make it idle much lower when it's cold 'cos its already good...just when it's hot.
The back pipe on the ISCV is blocked with a rubber cork, same with the tube coming from the engine, what would happen if I was to put a hose between the two?
 

homeskillet305

New Member
Sep 11, 2008
54
0
0
Miami, FL
On my car, when i disconect the battery the idle air control valve wont operate. After about two hours of driving i'll notice the idle change. If your ecu doesnt have 12v all the time on the right wire i think its b+ (even with the car off) it will reset every time you turn it off.