RE: Tools for correct mixture adjustment

[Jonas Karlsson <jkarlsso@metabolex.com>]

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

Aaron Ness wrote:
>I've heard that I can adjust the idle speed on my 'rocco myself, 
>but that I
>should take it to a shop to have the mixture adjusted properly.  
>I've also
>heard that I should be able to fix any problem with the fuel 
>injection
>system at home.  As you can see, there's a contradiction here.  
>What
>resources and tools do I need to correctly set my mixture?  I 
>have a decent
>multimeter, a timing light, a tach/dwell/volt meter, and a good 
>brain.  I've
>heard that I need a Bentley book and a pressure gauge with a 
>T-fitting.  Is
>this correct?  Is there anything else?  I want to lean out my 
>mixture
>because my plugs are black, but I want to do it right.
>
>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
>
>
>--
>To unsubscribe, send "unsubscribe scirocco-l" to 
>majordomo@scirocco.org.
>If you experience other problems, email: 
>scirocco-l-probs@scirocco.org
>
>--------------------------
>Status: U
>Return-Path: <majord@neubayern.net>
>Received: (from daemon@localhost)
>	by InterJet.metabolex.com (8.8.5/8.8.5) id LAA02674
>	for <jkarlsso@metabolex.com>; Tue, 10 Aug 1999 11:21:12 -0700 
>(PDT)
>Received: from UNKNOWN(207.225.26.93), claiming to be 
>"mail.neubayern.net"
> via SMTP by InterJet.metabolex.com, id smtpdMV2670; Tue Aug 10 
>18:21:10 1999
>Received: from majord by mail.neubayern.net with local (Exim 2.05 
>#2)
>	id 11EGSy-0000Y3-00
>	for scirocco-l-outgoing@neubayern.net; Tue, 10 Aug 1999 12:17:40 
>-0600
>From: "Aaron Ness" <Aaron@makuta.com>
>To: "'scirocco'" <scirocco-l@scirocco.org>
>Subject: Tools for correct mixture adjustment
>Date: Tue, 10 Aug 1999 13:12:15 -0500
>Message-ID: <001701bee35b$e2104a00$190a0a0a@m11>
>MIME-Version: 1.0
>Content-Type: text/plain;
>	charset="iso-8859-1"
>Content-Transfer-Encoding: 7bit
>X-Priority: 3 (Normal)
>X-MSMail-Priority: Normal
>X-Mailer: Microsoft Outlook 8.5, Build 4.71.2377.0
>X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2120.0
>Importance: Normal
>Precedence: bulk
>Sender: Majordomo <majord@neubayern.net>
>
>



--
To unsubscribe, send "unsubscribe scirocco-l" to majordomo@scirocco.org.
If you experience other problems, email: scirocco-l-probs@scirocco.org