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Re: CIS warmup query for Todd 83-900T, Kevin K, others... Posted by Dana [Email]  (#2822) [Profile/Gallery]
(more from Dana) on Fri, 6 Jan 2012 09:27:55
In Reply to: CIS warmup query for Todd 83-900T, Kevin K, others..., Micah in NC, Fri, 6 Dec 2002 12:40:19 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I do follow your description of the start transition. I still have the black tipped 25C (75F) temperature switch in my 85 8V base. However, my own experience has a slightly different description of its operation. This switch is wired in series with thermal time delay sensor which turns on the cold injector valve continuous for up to 9 seconds max during start cranking. So in my case, if the water thermosat housing reaches above 75F (switch opens above 75F) or up to 9 seconds has passed (thermal time delay switch), or the engine head temperature is above 45C (113F, thermal time delay switch) then the continuous cold injector spray does not operate during cranking. The fuel ratio is held at 60/40% time ratio during this cranking time and up to 2 minutes by the enrichmnent relay. If the engine needs more enrichment during acceleration after the cranking period but before the 2minutes are up, a intake header vacuum switch will pulse the cold injector valve open to provide the enrichment if the engine is still cold (<75F). For this time the ECU fuel ratio is normally locked at 60/40% timing ration. If the engine has at least reached 75F (the cold injector valve is disabled) then the intake vacuum switch (< 0.3 atm) allows the ECU to increase the fuel ratio from a fixed 60/40 to 92/8 during acceleration via the enrichment relay. Now normally the 60/40 fixed fuel ratio would be "unlocked" and put under control of the O2 sensor in the 84 model but in 85 SAAB added another 110F switch between the X1 terminal of the 8599425 relay (blue relay) and ground (body chassis).
This additional new normally closed temperature switch (opens above 45C, 110F) connects pin #12 of the ECM and X1 of the 425 relay to ground if the engine temperature is below 45C (110F).
Anytime the ECM pin 12 is grounded by this switch or the enrichment relay via X1 the 60/40 lock is maintained.
Dana
posted by 129.57....
, Fri, 6 Jan 2012 09:27:55 <-- Viewing This Message
, Fri, 6 Dec 2002 13:06:54, Fri, 6 Dec 2002 15:29:28
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