Matt Partain Posted May 17, 2006 Share Posted May 17, 2006 Hey guys, I am cleaning up my engine compartment, and the associated wiring. I gave a little relay that is connected to the plastic wire holder on the firewall. In my Chiltons manual it says that this is a TSC realy, and is connected to a TSC sol. What is this? This realy is not connected to anything on my car. Should it be? What does it do? Thanks, Matt Link to comment Share on other sites More sharing options...
Jim Boczar Posted May 18, 2006 Share Posted May 18, 2006 It's called TCS transmission controlled spark. Consist of a relay on firewall, wiring to a solenoid on the intake manifold, a temperature sending unit in the cylinder head, vacuum hoses from carb to distributor and a sensor in the transmission. Purpose is emission related to stop vacuum advance to distributor in low forward gears. I am sure this has been discussed before so try search on TCS for more info. A lot of owners removed them and went with direct vacuum hose from carb to advance unit on distributor bypassing solenoid. Link to comment Share on other sites More sharing options...
Rob Peters Posted May 18, 2006 Share Posted May 18, 2006 Matt, Jim is correct. I was not aware it was an emissions thing, I was told by the Chevy Dealer that it was a performance thing once the car entered third gear on the automatic transmission. It is all controlled by a pressure switch on the front passenger side of the transmission. I was told by the tranny guy at my local dealer that once the car enters high (3rd gear) the pressure switch on the tranny senses the pressure change and this causes the solenoid mounted on the intake manifold to open providing vacuum to the distributor spark control to advance the spark slightly for better performance in high gear. The pressure switch on the tranny was recently discussed here on the boards because mine started leaking recently and was leaving a nice trail of tranny fluid everywhere I went. Rob Link to comment Share on other sites More sharing options...
Matt Partain Posted May 18, 2006 Author Share Posted May 18, 2006 This is exactly why I love this club and message board. Thanks guys. I'll just do away with it. It sounds like it won't hurt anything to loose it. It wasn't hooked up anyway. Matt Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2006 Share Posted June 12, 2006 Sweet discussion. I just started working on my 1970 400 SB, when I found the TCS connector wedged in with some other wires (Solenoid long gone). After reading the Haynes manual, I figured out what it was and why it was there (combination of performance and emissions-though I think more in line with adhering to emissions w/o losing performance). None the less, swing by your local Pep boys/AutoZone and read pages 184-188 of the Haynes manual. It will explain it all in those pages. Link to comment Share on other sites More sharing options...
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