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boyt911sc boyt911sc is online now
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Join Date: Mar 2002
Location: Philadelphia, PA
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CSV operation.......

Quote:
Originally Posted by theiceman View Post
Hey Tony

Was reading this with great interest . Do you know how the car is wired. I thought I read somewhere that the cold start injector was wired to the starter motor. iS this via the thermo time switch

I am strying to understand how it works .. so if you crank the motor for 2 seconds and it starts how long does the cold start injector fire for ? is it a MAXIMUM of 8 seconds as the engine cranks then the TTS switch cuts it off ?



Theiceman,

There are several wiring connection configurations for the CSV in CIS (911). The early one has a direct connection to the CSV and the later passing through the starter. If you look closely to the factory wiring diagrams, they are basically the same. To complete the circuit, the CSV depends on the TTS (thermotime switch) for ground contact. Below 113°F, the TTS is grounded. Above 113°F, the TTS is not grounded (open switch/contact). To prevent prolong operation of the CSV that could flood the engine with fuel, the TTS has a built-in heater that limits the operation to 8 sec. (+|-).

You could bench test a TTS by applying 12 volts to it and monitor the ground contact of the body to the chassis. Approximately after 8 sec., the ground contact to the chassis will open. Thus preventing the CSV from further operation. Contrary to the myth that a CSV will operate above 113°F as long as the TTS is good is false. If it did, there is a wiring anomaly in the system.

To answer your question, power to the CSV comes from the ignition switch @ terminal 50 (#1 @ 14-pin connector) and this is the yellow wire. The yellow wire goes to:

'74~'75.............from 14/1 to throttle valve switch (F25) then to TTS & CSV.
'76~'76.............from 14/1 directly to TTS & CSV.
'78~'83.............from 14/1 directly to starter solenoid @#50 to #16 (different starter connections from previous years) to TTS & CSV.

Tony

Last edited by boyt911sc; 11-08-2016 at 02:30 PM..
Old 11-08-2016, 02:27 PM
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