RE: Tools for correct mixture adjustment

["Aaron Ness" <Aaron@makuta.com>]

The contradiction lies in the fact that some people say I *must* take it to
a shop to get the mixture adjusted correctly, and others had mentioned that
I could do this myself.  From what you say, it's clear that I can do it.
Now all I have to do is buy a Bentley manual, which I planned to do sometime
anyway.

Thanks for the input!

Aaron
'70 Bug - hibernating
'84 Scirocco - Woo-hoo!
Sand rail - for sale or trade in Columbus, IN
'87 Nissan truck - Soon to be for sale

> -----Original Message-----
> From: Majordomo [mailto:majord@neubayern.net]On Behalf Of
> Jonas Karlsson
> Sent: Tuesday, August 10, 1999 6:49 AM
> To: 'scirocco'; Aaron Ness
> Subject: RE: Tools for correct mixture adjustment
>
>
> Ummm, where's the contradiction.
>
> 1. idle speed:  The "basic" way to adjust is with the idle adjusting
> screw on the back of the throttle body. Timing and mixture
> will affect
> idle speed so these should be set first.
>
> 2. Mixture: You set the mixture by adjusting the ?control
> plunger? height
> in the fuel distributor. There is a 3mm allen screw
> accessable through a
> hole (which is sometimes covered & needs to be drilled out)
> on the Fuel
> Distributor. For proper adjustment, the CO is measured while
> the screw
> is turned, until the right CO count is reached. That is why a shop is
> "needed" for proper adjustment (gas analyzers are $$$). You can use a
> dwell meter connected to the Oxygen sensor for an "at home"
> check, and
> this works well. The Bentley "bible" describes this procedure.
>
> 3. FI problem/fixes:  The CIS/CIS-E fuel injection systems are pretty
> simple to work with. Replacing faulty components is easy. The
> trick is
> to find which part is busted. This is where the fuel pressure
> gauge with
> the T-fitting is necessary. Again the bentley describes the
> procedure.
> Basically by comparing system pressure and control pressure
> at different
> times (on, off, etc.) you can find out which part is not working
> properly.
>
> BTW, if anyone is interested in understanding Bosch Fuel
> Injection, there
> is a great book that was recommended a while back. Called
>
> Charles O. Probst's
> "How to understand, service and modify
> Bosch Fuel Injection & Engine Management"
>
> I just got it from Borders.com for $24 + shipping. It really
> describes
> the functions of all of the componends etc. It's awesome.
> Published by
> (who else) Robert Bentley Publishers
>
> HTH
> Jonas
> 85 Scirocco


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