[Mk2] [Turbo] What's the reason behind messing with adjustment screw on air flow meter?

[joemacmr2]

I know that screwing in makes richer and vice versa but why would someone want to touch it. Noticed mine has been tinkered with and car was running rich on the rolling road. Could this be the reason why?

I know it's made tamper proof from factory but was curious why previous owner would look to change the setting.

[Peter Gidden]

Noticed mine has been tinkered with and car was running rich on the rolling road. Could this be the reason why?

No. The idle mixture screw has no effect on mixture other than at idle.

I know it's made tamper proof from factory but was curious why previous owner would look to change the setting.

Obviously had no idea what it's there for.

[joemacmr2]

It's stamped 81 which means 18.1mm. Should I set back to factory setting and never touch it again?

[pistol pete]

Sound like the best plan..

[blogsy]

So could you use it to bring down the emissions by leaning it out in order to pass the mot, before putting it back to factory.

[Peter Gidden]

So could you use it to bring down the emissions by leaning it out in order to pass the mot, before putting it back to factory.

Should never have to. If the screw is in it's correct position and the car can't get through a BET, it has a major fuelling problem somewhere.

[bobhatton]

It's stamped 81 which means 18.1mm. Should I set back to factory setting and never touch it again?

Yes