Idle Mixture

[stevetvrs]

Good evening all,

My 2.9 V6 S3 smells like it may be running a bit rich, and my MOT is due soon (car has no cats or lambda sensor, and has 2 x air flow meters). I've got a basic gas analyser, which I intend to use to check CO, and my query is, can the CO at idle be adjusted? Is it correct that adjustments can be made by turning the allen head screws in the air flow meters? Does this affect the whole rev range?

Any tips would be appreciated, as I don't really want to put it on the rollers, just to do this (big mortgage, two kids and no time )

Thanks guys

Steve

[stevetvrs]

Boing

[S3Swiss]

Did this myself when got a s/h air flow meter. Adjust the mixture by screwing the allen headed bolts on the air flow meters in or out. Mine ran ok on the settings I set (with my cheapy gunson analyser) but when I gave it to my local Ford dealer to check along with timing after moving distributor, he richened it. It now runs better, but does have more of the 'air de petrol' whiff about it! I can live with that rather than run too lean a mixture.
Edited to add - cost £100 which included FAST test (Ford test kit), timing and mixture check at Ford main dealer. He seemed quite happy to see an old V6 as he said it was more interesting than all the new-fangled engines!!

Edited by S3Swiss on Monday 23 July 18:40

[Jed-S]

According to the Haynes Sierra V6 manual and looking at my spare airflow meter there is an allen screw adjustment on the side with the black plastic cover next to the inlet pipes.
I've never tweaked mine so I'll list the manual:

Get engine to full temperature.
Run at 3000 rpm for 15 secs
Let it idle and you have 30 secs to adjust the mixture. It does say adjust the front one first and if the mixture doesn't get lean enough then adjust the rear. Quite how that translates to us I don't know. If it was me I'd do them both by the same amount.
After 30 secs if it still isn't right then run to 3000rpm again etc.

[stevetvrs]

Thanks guys