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IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now. Visit Preferences to set your user name Summary of change: SAAB CDI CASSETTE INFO Schematic of the CDI Cassette on a SAAB 9-5 1998 http://www.vems.hu/files/saab cdi schematic1.gif Translation of the text: Trionic T7 does not use a cam position sensor which is usually a must for sequential knock regulation and injection. During startup the engine controler doesn't know which of the cylinders 1 and 4 is in the compressions stroke, as a result the controller fire both 1 and 4 at the same time. The same is true for ignition on cylinders 2 and 3. The controller has to determine if the combustion occur in cylinder 1 or 4 and 2 or 3 respectively. This is done in the following way: One of the primary coil connections is connected to the spark plug as usual but the other connection is not grounded as on a common ignition system but is connected to an 80v voltage. This means that there is an 80v potential over the spark gap except when the ignition occur. When a combustion occur the temperature in the combustion chamber is very high, the fresh gas is ionized and start to conduct current. This means that a current flow over the spark gap without creating a spark. Because of the current flow over the spark gap the voltage over the spark gap will drop a lot. ''The voltage drop over the gap will be proportional to the pressure and temperature in the combustion chamber. The italics part is heavily simplified and wrong -Jörgen'' 430=Engine Controle Module (Trionic 7) 229=System Relay Trionic does not have camshaft position sensor, it uses ion-sense in the CDI cassette to tell ECM which cylinder that is combusting. In CDI cassette there are two "DET" components which means detonation sensing, one for cylinder 1+2 and one for cylinder 3+4, the "K" means signal upon knock and the "C" means signal upon combustion. Upon start the ECM does not now which cylinder of number 1 and 4 that is in compression stroke and which that is in exhaust so ignition will happen on both, after that the ion-sense component of the CDI cassette will sense which cylinder that actualy did a combustion and voilá - we have sync... // Michael Pihlblad a.k.a. glidarn Optional: Add document to category: Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.