Cold start High idle

[Old School]

The 1JZ soarer engine in the Supra has a really high idle (about 3K or more) when it is first started. Once it warms up, it idles just fine. I can't seem to find out how to adjust the cold idle setting. Any experience here?

 

[states1j]

Tps maybe? Have you checked anything yet?

 

[te72]

I've heard of the ISCV causing some strange issues, but they tend to cause low idle symptoms. Things I would check include the TPS, the ISCV, the mechanical adjustments on the throttle body, and possibly the timing. How does it run otherwise?

 

[Old School]

Actually, it runs just fine. I am going to take off the ISCV and see if it is getting the correct voltages. You think it would be a simple stop adjustment, but I can't see any movement on the throttle body as it warms up.

 

[f00g00]

The throttle body is mechanical and only moves from the throttle cable. Vacuum leaks can cause high idle but not that much.

 

[Dylan JZ]

does anyone not really have a cold-start period? I live in FL and it doesn't get too cold (40deg. max usually), but my car will idle up to 1000rpm max when first started, unless I use the pedal.

 

[JPsToyota]

does anyone not really have a cold-start period? I live in FL and it doesn't get too cold (40deg. max usually), but my car will idle up to 1000rpm max when first started, unless I use the pedal.

I would love not to have a cold-start period at all, as I want rpms to be as low as possible as the oil first circulates and warms. I haven't figured out how to pull that off quite yet, as if I adjust anything or try to close the ISCV any more, I will get too low of an idle when fully warmed. Right now it's 1500+ right at startup, settles to 1300 and gradually lowers from there to 650.

I haven't played around with it alot, but it's coming soon on the list of crap to work on

 

[te72]

does anyone not really have a cold-start period? I live in FL and it doesn't get too cold (40deg. max usually), but my car will idle up to 1000rpm max when first started, unless I use the pedal.

Generally speaking mine idles anywhere from 900-1100 rpm. However, my ISCV is pretty much shot, so it's all mechanical adjustment to get mine to where it will be consistent. On a rare occasion the ISCV decides to work and it will idle about 1300-1400, and it gets COLD here.