AFM Question

[TMRnoV]

Removed the AFM's today and wondered why the upper one (S2 stacked afm's) is fairly black inside and the lower one is quite clean, both only pass air so why the carbon deposits ??

[Gerald-TVR]

Do you have a hose running from the oil filler cap to the air filter? If so is it closer to the upper AFM? If it is there's you culprit!

[Sandgrounder]

When I bought my S3 in April, one of the first jobs I did was replace the air filter (as the original was falling apart. I took the AFM's off and both were very black indeed.

I tried cleaning with Carb cleaner but not much difference. Didn't want to risk damaging the heated wire by attempting a scrub with scouring pad.

Car seems to run ok, though idle is not perfect.

[Road2Ruin]

Quite probably the breather pipe as Norman says. You can remove this and fit a small filter instead. I cleaned my with contact cleaner.

[TMRnoV]

Thanks guys, breather pipe is probably the culprit as Norman said, so will ditch it for a catch tank/filter, any recommendations ??

[TMRnoV]

Didn't stop me from getting curious though



Probably not user serviceable then

[phillpot]

TMRnoV said:

any recommendations ??

Google (or Ebay) "Pipercross breather filter"

TMRnoV said:

Probably not user serviceable then

the wiper track can be (very carefully) cleaned, dirt or tarnish can build up particularly on cars that haven't been used for a long time.

Edited by phillpot on Friday 16th November 19:02

[GreenV8S]

phillpot said:

TMRnoV said:

any recommendations ??

Google (or Ebay) "Pipercross breather filter"

Those filters are really designed to filter the inlet vent of PCV systems, not to work as a breather (outlet). The breather gases contain oil mist which will clog those filters quite quickly - as well as leaving an oil residue around the area. If you don't want to use a recirculating (PCV) breather system then your best options are to add a catch tank, or direct the breather hose down to the bottom of the engine bay (while staying clear of hot exhausts).

[phillpot]

GreenV8S said:

your best options are to add a catch tank

and one of those funny little filters !