Motronic Afm Mixture Screw

[dino20vt 3]

Following on from this;

 

http://forum.205gtidrivers.com/index.php?showtopic=125873&st=0

 

There's a small chance I've cured what was causing the ropey idle but I confuse things just yet.

 

As the idle screw doesn't physically come to a stop in either direction does that mean it will only richen or weaken the mixture by so much and any subsequent turns won't have an effect? But turning the opposite direction will.

 

Eg tuning anti clockwise to weaken mixture for so long till it won't get any weaker then turn clockwise to richen.

 

Can turning too many times one way damage it?

[dee205 3]

I take you mean the mixture screw and not the idle screw - this is on the throttle body..

 

The mixture screw lets a certain amount of air bypass through the afm. If you screw it down fully it will shut or the bypass hole. If you unscrew it completely and remove it ( this envolves pulling the screw out the last half and inch) the maximum amount of air will be allowed through the bypass. I've seen a few running without the screw so they can get lower Co levels.

 

That's the way it was explained to me anyhow!

[dino20vt 3]

I'm on about the idle mixture screw on the air flow meter on an Mi16. Not sure about an 8v but the 16v screw is connected to what looks like a variable resistor inside.

[KRISKARRERA 2 1 Cars]

As the idle screw doesn't physically come to a stop in either direction does that mean it will only richen or weaken the mixture by so much and any subsequent turns won't have an effect? But turning the opposite direction will.

 

Eg tuning anti clockwise to weaken mixture for so long till it won't get any weaker then turn clockwise to richen.

 

Can turning too many times one way damage it?

Yes, yes, and not sure.

I've done this with mine and had no adverse effects. Of course you're really only supposed to adjust this with a fully warmed up engine and using an exhaust gas analyser.

[dino20vt 3]

That's the trouble, when its warmed up the idle is a pig to keep stable thus making it near impossible to set up on the gas analyser plus we were short on time.

 

This weekend I plan on somehow keeping the butterflies fully closed to keep it at a sensible idle speed and then attenpt to set the mixture.