Re: Mixture Adjustment

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <000d01beadfe$9aea5720$acb935cf@WWICS.wwics.com> "Dan Sinclair" writes:

> This is a dumb question, but I've confused myself and need a second option.

The only dumb questions are the ones that aren't asked.

> The Bentley indicates that the mixture (CO) adjustment screw should be
> turned clockwise for (+) and counter-clockwise for (-), suggesting that
> clockwise will increase the CO level, and counter-clockwise will decrease
> the CO level.  So, and please correct me if I'm wrong, clockwise (+) is
> enriching the mixture, and counter clockwise (-) is making it leaner -
> correct?  The lower the CO number, the leaner the mixture, right?
>
> I'm going to have to take my '88 90 in to have the mixture checked via a CO
> meter, but I want to understand what they'll be adjusting if necessary.

You're correct.  I would add the general note that you should always
approach the target from the 'richness' direction - i.e., go rich
(high CO) and move towards lean.  If you get it wrong, go back 'rich'
(counterclockwise) and aim for where you should be from that direction.

> Also, I determined that my dealer or the previous owner's mechanic removed
> the rubber plug that hides the mixture adjustment screw, but didn't replace
> it.  The hole has been open for months if not years depending on who removed
> it.  Would this have any effect on the engines operation.  Can air enter the
> intake system through that hole?

Yes, but negligible.

--
 Phil Payne
 UK Audi quattro Owners Club