Cold Start up issues

[Davie Bow]

Hi Guys ,
a bit more info/advice needed please,
on cold start up my car sounds like a bag of spanners , its only when its cold and settles down within a minute or two or within a few hundred yards of pulling away , not sure if this is normal or not but my S8 and S6 weren't this noisy .

i have checked the oil and we're fine there , i have official Vagcom from the days of owning my other 2 on and it threw up fault codes "miss fire on cylinder 3 and cylinder 8 . So i'm wondering if this could be coil packs / plugs and contributing to the problem.

once the car is warm , the engine sounds sweet and pulls like a train with no flatspots

Any ideas or anyone had similar issues ??

cheers
Dave

[Shoppinit]

Could be misfire when cold. Maybe an SAI problem causing weak mixture / air leak when activated.

[Davie Bow]

Could be misfire when cold. Maybe an SAI problem causing weak mixture / air leak when activated.

What's the SAI ? , cheers

[Shoppinit]

= Secondary Air Injection

[Weiß-sechs]

The rattle is probably unrelated to the fault codes. I had this with mine from cold....sounded like a million miler taxi for half a minute or so, turned out to be the cam chain tensioner. Both cams on each bank are connected by a chain and the tensioner for these is hydraulic; they wear over time and miles so don't tension the chains correctly until the oil has thinned enough. From memory, off side is an easy fix, near side a biatch....or vice versa

[Davie Bow]

Thanks guys ,
I'm gonna do the cam belt again anyway just for my own piece of mind so will do the thermostat and chain tensioners at the same time .

What's the situation with these secondary air intakes , are they likely to need replacing or can i just remove and clean them ?

[bam_bam]

...just for my own piece of mind so...

Well that sounds painful.

The SAI can be deleted, it just fills with water anyways. I can't remember if it needs to be mapped out or not.

[Mɐʇʇ]

It does. I tried it with SAI removed but no changes to the map.

There's 2 elements that need to be mapped out, ideally, to allow you to remove all the gubbins.
Or, if you just remove the pump & the valves - blanking off the ports in the head, it's a simpler change to the map and you can just leave the solenoid valve on top of the intake manifold electrically connected (but not connected to the manifold etc)

I did the latter.