Adjusting Throttle Stop Screw...Q's...

[Alpine003]

The previous owner purposely ran the idle a bit on the high side to cover up the rough idle problem. After getting a few new parts, I adjusted down the throttle stop screw so the throttle plate would remain closed.

Question is, should the throttle plate be all closed or should I set the throttle stop screw to have the plate barely opened? Not sure what the factory settings are. Anyone? Bueller?

[Vladi]

During idle i think the throttle plate should be closed because the engine is runing with the air provided by the ICV (Idle Control Vlave). My throttle plate doesn't open at all at idle. :rolleyes:

[Alpine003]

During idle i think the throttle plate should be closed because the engine is runing with the air provided by the ICV (Idle Control Vlave). My throttle plate doesn't open at all at idle. :rolleyes:

Thanks. That's how I have mine currently setup but I just wanted to make sure.

[Gunni]

I was just contemplating this last night,

stefan325i has always had a sharp throttle response, even with the afm in place,
while most m1.3 325i´s I have encountered have had bad of throttle response,

I was installing a M30 afm into a 325i yesterday and we fixed the idle problem and rough running by adjusting the afm wheel,
but it got me thinking,

if the throttle plate is adjusted to be open enough to idle, and the ICV is only used to compensate (as it should be) would throttle response of idle be better as the air is travelling from there ?
Also the TPS would have to be re adjusted on a M20 for the idle switch,

anyway I was just wondering that last night,

[Alpine003]

if the throttle plate is adjusted to be open enough to idle, and the ICV is only used to compensate (as it should be) would throttle response of idle be better as the air is travelling from there ?

Not sure if I understand you correctly but for what it's worth, when my idle stop screw was adjusted so the plate was open just a tad, my throttle response and acceleration were both better.

I've read in some other posts that the plate is suppose to be barely open just a tad but I'm getting mixed answers. Unfortunately, I don't have access to any factory manuals for reference.

[Gunni]

no your reading me right, i.e my assumption was actually your results,

as it´s with the stock setup, the idle is not done by the ICV, it´s supposed to help with AC and heavy electrical load , not stabilise normal idle,

I think that if you close the ICV route and adjust idle with the stop screw that that is the right way, i.e when you drop the throttle the icv´s businees is provide MORE air not take air to get good idle,

I´ll try it on his car and see what happenes

[Vladi]

The ICV valve adjusts idle air intake. Why would it be called "Idle Control Valve"? :D Where else would the engine get it's air at idle if the throttle plate is closed? Check any BMW engine you want, it's the same AND the right way.
The compensation for heavy electrical loads and A/C is done by the ECU through the ICV valve wich lets MORE air through into the intake.

[GTVeloce]

I think the throttle plate should be opened a 'little'...barely during idle. Same setup in the GTV6; the fty manual specifies using a vacuum gauge to set up the idle throttle position through a vaccum port at the TB!

[Gunni]

The ICV valve adjusts idle air intake. Why would it be called "Idle Control Valve"? :D Where else would the engine get it's air at idle if the throttle plate is closed? Check any BMW engine you want, it's the same AND the right way.
The compensation for heavy electrical loads and A/C is done by the ECU through the ICV valve wich lets MORE air through into the intake.

What I´m saying is that when you open the throttle 3cm with the pedal it will be less open if pulled from a dead close then from beeing sligthly open, thus more air from the 3cm movement if it´s not completely closed, and I´m sure that means better throttle response from idle.

[Vladi]

oh, yeah. :D

[Alpine003]

Anybody have a factory manual for reference to know for sure if the throttle plate is suppose to be closed all the way? I can see both arguments but just wanting to know what the factory recommends.

[Vladi]

Man, check any E30 you find and you'll see the throttle plate is closed at idle.

[Alpine003]

Man, check any E30 you find and you'll see the throttle plate is closed at idle.

I wish I could but there are none around me. ;) I'll just take your word.