High-RPM Cold Start

AGlobalThreat

AGlobalThreat

Acceleration
Apr 4, 2005
991
0
0
Santa Clarita
This has happened 3 times total, I think once a week the last 3 weeks.

I will start the car (From a cold start) and the RPMs will jump up to around 2K and stay there. Also, it sounds like there is a big air leak coming from the center of the firewall.

Then, I shut off the engine. I crank it back up, it fires up, and idles perfect and drives fine, and then it doesn't happen for another week or so.

I have a DDP and I don't know if thats whats making the air noise or what is causing it. This problem is totally random, and disappears when I restart the engine.

Anyone have any ideas/suggestions?
 
AGlobalThreat

AGlobalThreat

Acceleration
Apr 4, 2005
991
0
0
Santa Clarita
On regular cold start it will idle higher, 1250 rpms I think. Then drops as it warms up.

But these few times it has idled up past 2000 and wasnt dropping so I restarted the engine.
 
AGlobalThreat

AGlobalThreat

Acceleration
Apr 4, 2005
991
0
0
Santa Clarita
Isn't it called the IACV on the 1jz (Idle air control valve)?

Or is it ISC (Idle speed controller)?

Or is it ICS (Idle controller of speed)? :p

I tried revving it a bit and went over 3k and when it finally dropped back down the lowest it got was 2k. Restarted the engine and everything was peachy, back to idling lower like it should.

Im hoping I can order the part new from Champion Toyota... unless someone knows a place I can get it?
 
1JZ A70

1JZ A70

Banned
Nov 3, 2008
13
0
0
Australia
High RPM cold starts are a very annoying problem for a lot of JZ owners. The worst part is the valvetrain rattle before oil pressure has had a chance to reach the head.

This problem is easily overcome by installing a restrictor plate inbetween the idle valve and intake manifold.

From memory the factory gasket is slightly larger than the port which is huge and flows a lot of air, hence the high rpm. I would say its easily 25mm in diameter. We installed a restrictor plate with a hole just 6mm in diameter and have never looked back. Mind you our coldest winter is only 10'c. You may run into idle stability problems under this, but then its only a 5 minute job removing the restrictor plate and putting it back to normal.
 
AGlobalThreat

AGlobalThreat

Acceleration
Apr 4, 2005
991
0
0
Santa Clarita
It hasn't happened since I last posted, the only thing I've been doing is turning the Key to ON, letting fuel pressure build and the aem uego countdown, then put the Key back to off, then back to on, and then starting it a few seconds later. Hasn't happened since.
 
Zumtizzle

Zumtizzle

Can't Wait to Be King.
Oct 21, 2006
2,825
0
36
Sac-Town, NorCal
AGlobalThreat;1250227 said:
Isn't it called the IACV on the 1jz (Idle air control valve)?

Or is it ISC (Idle speed controller)?

Or is it ICS (Idle controller of speed)? :p

I tried revving it a bit and went over 3k and when it finally dropped back down the lowest it got was 2k. Restarted the engine and everything was peachy, back to idling lower like it should.

Im hoping I can order the part new from Champion Toyota... unless someone knows a place I can get it?
Click to expand...


Take it off and clean with brake clean..3 Philips screws

thats a 400 dollar part..........
 
AGlobalThreat

AGlobalThreat

Acceleration
Apr 4, 2005
991
0
0
Santa Clarita
I cleaned it about a year ago when my idle was messed up. I'll try starting my car the normal way and if it happens again I'll take it off and take a look.

Thanks for the help everybody
 
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