Driveability with no ISC valve?

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cnewingham

Guest
I picked up a FFIM but the ISC valve opening was welded closed so now there is no provision. I dont want to run a standalone system yet but also dont want to have any major issues. I plan to run just the stock ecu, lex afm, afpr, 550s. Should I just have the hole opened back up? what do you guys think???
 
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SySt

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Mar 30, 2005
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Opening the hole back up is not a bad idea. However you could just adjust the throttle body to keep a certain amount open that will give ok idle quality.
 
bigaaron

bigaaron

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Apr 12, 2005
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I hear there is a mechanical isc on some older (European?) cars that is open when the engine is cold and slowly closes as it gets warm. I would like to find out what vehicle it came on specifically, because it sounds like a simple and easy solution. It just bolts to the engine block and has a vacuum inlet and outlet.
 
bigaaron

bigaaron

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Idling at 1k rpm or holding down the gas pedal for the first few minutes could be considered a problem, just depends on what you are willing to deal with.

You can eliminate the isc and still be ok.
 
staticpat

staticpat

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Mar 30, 2005
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I run the Lexus and eliminated the ISC, and it works perfect. I just adjusted the idle up a little and it runs fine. You just need a way to let a little extra air bleed through the throttle body.
 
Reign_Maker

Reign_Maker

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Aug 31, 2005
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I wish I new that with the AEM I didnt need the ISC... When Ron made my FFI he asked if I wanted it, I said yes... Now, I hate looking at this tumor growing off the side of my intake... If the ffi wasnt already pilished, I think Id cut it off...
 
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cnewingham

Guest
I guess I could raise the idle but I hate to apply the additional wear on the motor till it warms up. Plus with forged pistons the slap will be worse when cold and my bores are already 85mm.
Aaron, lmk when you figure somethiing out as I am sure you will soon. Still contemplating on going the Stinger route but I am lost with Standalone set ups.
 
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dbsupra90

toonar
Apr 1, 2005
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yep no isc here, but i run speed density. my car idles fine on its own when cold, and my warm idle is ~800 rpm.

however, running the stock/lex afm your car is gonna be pissed.

i was talking to sean a while back about an isc from a nissan for his car. it works similar to what bigA describes. i'll see if he can post more info.

i think if you must use an isc the best way to go is remote mount.
 
marlonvip

marlonvip

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Sep 2, 2006
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dbsupra90 said:
yep no isc here, but i run speed density. my car idles fine on its own when cold, and my warm idle is ~800 rpm.

however, running the stock/lex afm your car is gonna be pissed.

i was talking to sean a while back about an isc from a nissan for his car. it works similar to what bigA describes. i'll see if he can post more info.

i think if you must use an isc the best way to go is remote mount.
Click to expand...


So If you run the Maft pro/speed density you dont need the ISC?
Just got a beautiful FFI without the provision for Isc and >I would just hate to cut /weld this thing on it???

Dbsupra90 you have made adjustment for the coldstart idle through the Maft pro or just adjustet the tb??

Thanks
Marlon
 
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dbsupra90

toonar
Apr 1, 2005
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marlon-

no you dont have to run one w/ that setup.

no changes to the coldstart, just adjusted the throttle body.

it effects the idle a little during warm up. but i always let the car get to about 150F before driving anyway.
 
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IJ.

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Mar 30, 2005
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You could always get a small solenoid T into a vacc hose after the throttle body hose from the other end to the accordian pipe so it draws filtered air then use a restriction to set your cold idle speed.

Cold start press a button inside the car to open the solenoid = fast idle

Car warms up press button to close the valve.
 
Jeff Lange

Jeff Lange

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Mar 29, 2005
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bigaaron said:
I hear there is a mechanical isc on some older (European?) cars that is open when the engine is cold and slowly closes as it gets warm. I would like to find out what vehicle it came on specifically, because it sounds like a simple and easy solution. It just bolts to the engine block and has a vacuum inlet and outlet.
Click to expand...

This is how idle speed is controlled on the 16v 4A-GE, although, it's mounted on the bottom of the throttle body, and has coolant flowing through it.
 
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dbsupra90

toonar
Apr 1, 2005
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IJ. said:
You could always get a small solenoid T into a vacc hose after the throttle body hose from the other end to the accordian pipe so it draws filtered air then use a restriction to set your cold idle speed.

Cold start press a button inside the car to open the solenoid = fast idle

Car warms up press button to close the valve.
Click to expand...

that would work i think. you could probably use a vsv for that.
 
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