1UZ High Idle speed

[JZK25]

I have a 1990 Celsior 1UZ running in my mates tonner. It runs well but idles very high at about 1400rpm which makes dropping it into gear a bit rough.
Anyone have an idea on either the cause of this or how to adjust it down?

The only thing that isn't wired in is the instrument cluster speed signal, I gather this may be causing the high idle but am not 100% sure.

 

[Loroh]

My conversion does this also, I just thought it was normal.
When mine warms up it settles back down to aprox 500rpm.

I just assumed The original car had better sound installation and you couldn't hear it.

Love to hear what other people say, cuz your right it's anoying sometimes

 

[JZK25]

It doesn't settle to normal idle speed, it stays at 1100 and up when warm which is excessive.

 

[Loroh]

sure the butterfly's not being held open a little? mine was doing that too at first.

 

[Lextreme II]

Check the deskpot and a radiator hose clamp. There is a radiator hose that goes into the throttle body and if the clamp is not position properly, it will be on the way of the TB and cause high idle. This is because the TB doesnt close all the way due to interferrence.

 

[KDog]

What Lex says,
+ throttle body sticking
Also sometime the ISCV needs a bit of clean and can become stuck.
They are usually the culprits.

 

[JZK25]

Ok, I didn't actually consider physical interference, thanks.

So pull the IAC and clean it also, to easy.

We spent about 2 hours doing laps of my neighbourhood callibrating the VDO speedo off speed2 today so didn't get a chance to check the idle speed problem.
It has autocal but couldn't get it to cooperate because it lost ign everytime we started it during the calibration procedure so had to do it manually by changing the pulse per km figure. It's now the only 70's Holden around with an accurate speedo so it was worth it.