Pinking when cold

[Brenjacques]

Hi all
Just getting through some more work on the scirocco, I've noticed some pinking when the engine isn't fully up to temp, it's fine once fully warm but for the first 20 mins or so it's pinking, not awfully but mainly on pulling off uphill or using a high gear at low speeds.

I've checked the ignition timing which is spot on, I did retard it a bit just to see if it helps but it hasn't really made a difference. Just wondering where to go from here, I did have it tuned up a few month back but I'm wondering if it's something to do with the mixture especially during warm up when the choke is in use. Any thoughts?

[chopperoli]

Mixture probably too lean, you could test by enrichening mixture, if it is that then you might need to adjust the choke

[Brenjacques]

Good suggestion as I was thinking this myself, the choke wasn't touched when the engine was tuned up so I did consider whether it needed some adjustment of the choke/accelerator screw. I'll back it off a bit and see if it improves things.

[mark1gls]

What fuel are you using?

[Brenjacques]

I use either BP or Shell premium/super unleaded. Been wondering if it could be something in the engine bay rattling that has a low resonant frequency but it has all the signs of pinking (lots of acceleration at low revs etc)