high idle when cold

[chriseclipse]

everytime i start my car cold, the motor would rev up to 3500rpm intill the engine warms up. this problem start about 4 year when got my car fixed by Mitsubishi because the ecu and tps crashed. this problem happened before any mods were done too the car. does any one know what it might be

thanks,
Chris

 

[91gsxboosted]

Does it rev up and hold, or does it go up and down? When its really cold out mine will go up to about 3,000 grand, and slowly go down when it's warning up. If it's jumping around it could be a sensor or a vacuum leak.
-Joey

 

[chriseclipse]

it would rev and stay at 3500rpm for about 3-4min before it would start the idle surge.

 

[project_tsi]

Most likely, your FIAV (Fast Idle Accelerator Valve) is working incorrectly. This valve is intended to open upon cold starts, working almost like a choke system. If this valve is stuck, or broken, your car will rev high until it reaches normal temp. The FIAV is located in the throttle body and can be cleaned.

I once was stupid and put an egg in my cooling system due to a small radiator leak. Soon I began having the same symptoms as what you are stating. A cleaned out my FIAV, and it fixed the problem. While your in there, I suggest replacing your gaskets and other proplem prone pieces in the throttle body.

 

[chriseclipse]

the fiav is located where the coolent lines connect into the throttle body, right? if so what do i use clean it out.

 

[project_tsi]

the fiav is located where the coolent lines connect into the throttle body, right? if so what do i use clean it out.

That is correct. This is a pic from a 90 model. The 91-94 will difffer slightly w/ a 2 piece design. Clean it out w/ carb cleanor or equivelant. Be sure to get all the gummed up stuff out.

About my previous statemet above. The FIAV actually acts as the exact opposite of a choke. Whereas a choke reduces airflow, the FIAV increases it to provide higher idling when cold.

 

[oldman]

1GB FIAV. BTW Dan, shouldn't you be porting?

 

[project_tsi]

1GB FIAV. BTW Dan, shouldn't you be porting?

Yeah I should. But shouldn't you be fixing your links??????

 

[oldman]

Yeah I should. But shouldn't you be fixing your links??????

Yea if I own vfaq.