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Re: CIS service manual (Excellent resource!) Posted by Gary Stottler [Email]  (#1463) [Profile/Gallery]
(more from Gary Stottler) on Tue, 9 Nov 2010 14:05:39
In Reply to: CIS service manual, DrewP, Tue, 9 Nov 2010 13:30:41 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Drew,
Thanks so much for publishing the pages regarding CIS - an invaluable resource, one really needs that for an understanding of the system to be able to trouble shoot effectively!
That said, the 1984 900 is a much later version and it has the Lambda closed loop (Oxygen Sensor and Catalyst) system in a more integrated form than the 99s. Also, as emission requirements got tighter and tighter, Saab and Bosch resorted to more and more "add ons" to the system such as timer relays, etc. to manage emissions. The problem area is always from cold to warm - it is difficult to control emissions when the engine is cold.
In my experience, the warm-up regulators tend to degrade after many years and cause problems in the warm-up region. If you are certain that your engine has good compression and that your ignition timing, spark plugs, and injectors are all in good shape along with good basic fuel pressure, then you might want to start looking at the control pressure delivered by the warm-up regulator. Also, a tired oxygen sensor can cause problems when the engine gets warm enough to decide to start reading the sensor, it can jump lean and cause all kinds of problems.
There really are no electrical problems with either the warm-up regulator or the auxilliary air valve which can cause this kind of problem - if either of those loses power, you will have a richer mixture or a higher idle speed during warm-up both of which will improve your driveability.
Gary
posted by 198.208.25...
_______________________________________ Gary Stottler
, Tue, 9 Nov 2010 14:05:39 <-- Viewing This Message
, Tue, 9 Nov 2010 16:55:10, Wed, 10 Nov 2010 06:06:23, Wed, 10 Nov 2010 06:50:13
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