high idle problem

[coupe5ohh]

so i have a 94gt with tfs1 cam,1.6 rr,cobra upper and lower with a 1in spacer and a mail order tune from dirtydirtyracing and 16* timing..he set my idle to 750rpm but it idles at like 1k rpm and will sometimes drop to around 750 but will jump right back up..what could be causing this?i can hardly tell my car has a cam cause of where it idles..any ideas?

 

[hottwheels04]

its the IAC you have to adjust it so it can idle right.

 

[coupe5ohh]

its the IAC you have to adjust it so it can idle right.

how?

 

[rz5.0]

reset your base idle

 

[auto_x5.0]

There's a 2mm(?) alan head screw on the back side of the throttlebody and you turn tighten it or loosen it as much as needed. At least that's how you do it on a fox car.

 

[toyman]

Did the high idle just start with the chip install or was it working fine and all of a sudden start to idle high. The solution will most likely be different in each case. If it's the first I would suspect it's the tune. If it's the second I would look to the 16 year old IAC as being the culprit.

 

[Addermk2]

Don't touch the IAC...

I'm pretty sure the guys at dirtydirty set your IAC scalars in the tune. You should drop your timing back down to 10? unless you were directed to do otherwise by the tuner. Also, you need to perform the disconnected IAC base idle relearn procedure.

 

[coupe5ohh]

Don't touch the IAC...

I'm pretty sure the guys at dirtydirty set your IAC scalars in the tune. You should drop your timing back down to 10? unless you were directed to do otherwise by the tuner. Also, you need to perform the disconnected IAC base idle relearn procedure.

how do i do the "disconnected IAC base idle relearn procedure?"

 

[coupe5ohh]

Also...whats is this Allen screw for?it looks like its for adjusting some thing..but what its on the part of the housing that connects to the IAC

 

[coupe5ohh]

Also decided to make a restrictor plate today when i get home

 

[ttocs]

can't remember what it is called but it does effect the idle. It will adjust the idle by letter some air past the butterfly but if it is opened up too much, when you shift the car will rev when you push the clutch in. there is a small passage that goes around the butterfly and when you tighten that screw, it closes the opening more, loosen it and it opens it.

 

[Addermk2]

DON'T TOUCH THE f*cking IAC.... DON'T RUN A RESTRICTOR PLATE... DON'T TAKE ADVICE FROM ANY OF THE JOKERS IN THIS THREAD

Is any of this getting through to you?


Disconnect the battery's negative terminal to reset/clear the computer's memory. Leave it disconnected for 30 minutes.
Disconnect the plug going to your idle motor which is located on the front of your throttle body.
Reconnect your battery's negative terminal.
Start the engine, and set the idle to the ~675 with the stop screw on the of the throttle body linkage arm.
Turn off the engine.
Reconnect the plug on the idle motor.
Make sure all accesories (radio, blower motor, a/c, lights, etc) are off and start the engine.
Let engine run for two minutes.
Turn engine off and wait two minutes then restart engine and let idle for two minutes with all accesories on.
If everything was done properly the EEC-IV (read: computer) should have learned it's new idle.


If you do all of this, exactly as described... and your cars idle still fluctuates, you should consider changing your O2 sensors if they are old.

 

[toyman]

its the IAC you have to adjust it so it can idle right.

The IAC can't be adjusted. You can adjust the air trim but that is for smoothing the idle. The IAC is not opened like door half way, its either open or closed completely. The EEC sends many pulses per second to flutter the IAC open and closed. It flutters so fast that you shouldn't notice any RPM fluctuation with a functional IAC. This fluttering is called duty cycle, when it's calculated as a percentage of on time. So when the IAC is off it is at 0%, when it is fully open it is at 100%, and any RPM in-between. The IAC may or may not be the source of the problem but it's important to know how these devices work if one is to get any understanding of the principles involved.

 

[rz5.0]

DON'T TOUCH THE f*cking IAC.... DON'T RUN A RESTRICTOR PLATE... DON'T TAKE ADVICE FROM ANY OF THE JOKERS IN THIS THREAD

Is any of this getting through to you?


Disconnect the battery's negative terminal to reset/clear the computer's memory. Leave it disconnected for 30 minutes.
Disconnect the plug going to your idle motor which is located on the front of your throttle body.
Reconnect your battery's negative terminal.
Start the engine, and set the idle to the ~675 with the stop screw on the of the throttle body linkage arm.
Turn off the engine.
Reconnect the plug on the idle motor.
Make sure all accesories (radio, blower motor, a/c, lights, etc) are off and start the engine.
Let engine run for two minutes.
Turn engine off and wait two minutes then restart engine and let idle for two minutes with all accesories on.
If everything was done properly the EEC-IV (read: computer) should have learned it's new idle.


If you do all of this, exactly as described... and your cars idle still fluctuates, you should consider changing your O2 sensors if they are old.

Resting base idle is what I sugested. Just did posted how to do it.

 

[Addermk2]

DON'T TOUCH THE f*cking IAC.... DON'T RUN A RESTRICTOR PLATE... DON'T TAKE ADVICE FROM ANY OF THE JOKERS IN THIS THREAD

Is any of this getting through to you?


Disconnect the battery's negative terminal to reset/clear the computer's memory. Leave it disconnected for 30 minutes.
Disconnect the plug going to your idle motor which is located on the front of your throttle body.
Reconnect your battery's negative terminal.
Start the engine, and set the idle to the ~675 with the stop screw on the of the throttle body linkage arm.
Turn off the engine.
Reconnect the plug on the idle motor.
Make sure all accesories (radio, blower motor, a/c, lights, etc) are off and start the engine.
Let engine run for two minutes.
Turn engine off and wait two minutes then restart engine and let idle for two minutes with all accesories on.
If everything was done properly the EEC-IV (read: computer) should have learned it's new idle.


If you do all of this, exactly as described... and your cars idle still fluctuates, you should consider changing your O2 sensors if they are old.

Resting base idle is what I sugested. Just did posted how to do it.

yes, correct, I should have specified

 

[Win]

Don't touch the IAC...

I'm pretty sure the guys at dirtydirty set your IAC scalars in the tune. You should drop your timing back down to 10? unless you were directed to do otherwise by the tuner. Also, you need to perform the disconnected IAC base idle relearn procedure.

This

DON'T TOUCH THE f*cking IAC.... DON'T RUN A RESTRICTOR PLATE... DON'T TAKE ADVICE FROM ANY OF THE JOKERS IN THIS THREAD

Is any of this getting through to you?


Disconnect the battery's negative terminal to reset/clear the computer's memory. Leave it disconnected for 30 minutes.
Disconnect the plug going to your idle motor which is located on the front of your throttle body.
Reconnect your battery's negative terminal.
Start the engine, and set the idle to the ~675 with the stop screw on the of the throttle body linkage arm.
Turn off the engine.
Reconnect the plug on the idle motor.
Make sure all accesories (radio, blower motor, a/c, lights, etc) are off and start the engine.
Let engine run for two minutes.
Turn engine off and wait two minutes then restart engine and let idle for two minutes with all accesories on.
If everything was done properly the EEC-IV (read: computer) should have learned it's new idle.


If you do all of this, exactly as described... and your cars idle still fluctuates, you should consider changing your O2 sensors if they are old.

This

Plain and simple