tight valve lash rich a/f ratio

[excaliburcombo]

Hi EK9.org

Need some opinion are tight valve lash will causing rich a/f ratio. We having wideband road tuning and all seem ok (part tuning 14.7-15 AFR WOT 13 AFR). After 1 week we decided to do valve lash adjustment due to idle not stable. Checked valve lash a bit tight from factory spec. Readjust back to factory spec in 0.15mm and ex 0.17mm now idle back as normal. But notice my LTFT add fuel percentage more (12%). Before valve lash adjustment the LTFT (5%).

 

[Leej8]

Just reading though this and find it interesting,
Did you ever got to the bottom of this?
Was it your valve lash?

 

[excaliburcombo]

thanks leej8. From reading other HT thread someone said maybe tight valve lash will make AF leaner but the discussion didn't have more info. So we just re tune back and so far no issue.

 

[Leej8]

Thanks for your reply, glad it's running good now
All the best leej8.