Throttle Butterfly Gap On Idle - Making It Bigger - Screw In Or Out?

[ATK 137 1 Cars]

Sorry if it seems like a stupid question, want to try making the throttle body butterly gap a little bigger on idle to try to stop the hunting I get when cold sometimes...

 

Question is - throttle position screw - do I wind this in further or wind it out to make the butterfly gap bigger? I'm assuming wind it in a bit?

[Anthony 1,000]

Screw it in (clockwise) to open the throttle further, assuming of course the screw isn't seized.

 

Obviously you'll need to adjust the idle speed screw to bring the idle speed back down (clockwise) again from doing that, and you'll likely need to reset the position of the throttle switch too.

 

Hunting suggests it's over-rich though - try leaning off the AFM a few turns first (anti-clockwise)

[welshpug 1,626]

Surely the rr guy set that?

[ATK 137 1 Cars]

Surely the rr guy set that?

Yeah but the engine was warm when I got to Abercynon. I'm just tweaking it slightly to try to get it perfect, it doesn't always do it.

 

 

Screw it in (clockwise) to open the throttle further, assuming of course the screw isn't seized.

 

Obviously you'll need to adjust the idle speed screw to bring the idle speed back down (clockwise) again from doing that, and you'll likely need to reset the position of the throttle switch too.

 

Hunting suggests it's over-rich though - try leaning off the AFM a few turns first (anti-clockwise)

 

Cheers Anthony

[welshpug 1,626]

I wouldnt touch the throttle stop, just wind the air bypass screw out a touch.

[jackherer 543]

If it hasn't been done for a while you'd do well to fully unscrew the air bypass screw and then clean the oil and grime off the conical end until it is shiny which makes it more consistent.

[ATK 137 1 Cars]

If it hasn't been done for a while you'd do well to fully unscrew the air bypass screw and then clean the oil and grime off the conical end until it is shiny which makes it more consistent.

Yep already done, everythings had a thorough cleaning.

 

I wouldnt touch the throttle stop, just wind the air bypass screw out a touch.

 

This would raise my idle speed too much then wouldn't it? I was going to make the gap a little bigger by winding in the throttle stop screw then wind in the air bypass screw to bring the idle back down to 950-1000 rpm or so.

[welshpug 1,626]

only if you wind it too far.

 

easier to adjust that screw than to adjust the throttle stop then have to re-set the throttle switch.

[ATK 137 1 Cars]

Gotcha. Cheers, will give it a go.

Edited May 28, 2014 by ATK

[scbond 15 1 Cars]

My situation is pretty much identical. Had cold starting issues and couldn't work it out as I have no air leaks, changed the temperature sensor, checked the SAD etc. Ended up changing the AFM and it seems to have improved a bit (Maybe a placebo effect though). Still have a bit of a cold start issue/misfire on start but it isn't as bad anymore and doesn't last as long...plus I have around 1,000 rpm warm idle after setup.

 

Dunno if there's any other suggestions? Misfire suggests the AFM but swapped with another and it's still there, just not as bad. Spark plugs all look normal too.

[welshpug 1,626]

instead of blindly swapping AFM's you need to get it setup properly.

[ATK 137 1 Cars]

My situation is pretty much identical. Had cold starting issues and couldn't work it out as I have no air leaks, changed the temperature sensor, checked the SAD etc. Ended up changing the AFM and it seems to have improved a bit (Maybe a placebo effect though). Still have a bit of a cold start issue/misfire on start but it isn't as bad anymore and doesn't last as long...plus I have around 1,000 rpm warm idle after setup.

 

Dunno if there's any other suggestions? Misfire suggests the AFM but swapped with another and it's still there, just not as bad. Spark plugs all look normal too.

 

 

Can a misfire be caused by an AFM though? I would have thought a misfire would be more ignition-component related e.g. ignition amp etc. Dunno, I'm a novice myself.

[scbond 15 1 Cars]

instead of blindly swapping AFM's you need to get it setup properly.

 

I did do many times before with the old AFM and a couple of times since the new one. All according to Haines. With the old one it was almost impossible to get it to 600 rpm without it stalling. Was a lot easier with the new one.

[scbond 15 1 Cars]

 

 

Can a misfire be caused by an AFM though? I would have thought a misfire would be more ignition-component related e.g. ignition amp etc. Dunno, I'm a novice myself.

 

Apparently the AFM will cause it on a cold start. As for the ignition setup...plugs look healthy, leads look brand new and there's no misfire issue other than on startup.