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geezer#99 · 08-07-2012, 08:43 AM

Ezzy Pezzy!!
TCS
Transmission controlled spark (timing). That plug on the tranny is set up as a switch to ground. Used to control your vacuum advance until you're in 3rd gear. THere would have been a switch on the firewall (or engine) that had a vacuum line from your carb on one side and a vacuum line out of the switch to the vacuum pot on your distributor. The switch had 12v to it when your ignition key was in run position. THe switch would stay closed letting no vacuum to the distributor until you shifted to third and completed the electrical curcuit to ground. The switch would open and you'd have vacuum to your distributor.

08-07-2012, 08:43 AM	#2
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,783	Re: Help identify this mystery plug on three spd Ezzy Pezzy!! TCS Transmission controlled spark (timing). That plug on the tranny is set up as a switch to ground. Used to control your vacuum advance until you're in 3rd gear. THere would have been a switch on the firewall (or engine) that had a vacuum line from your carb on one side and a vacuum line out of the switch to the vacuum pot on your distributor. The switch had 12v to it when your ignition key was in run position. THe switch would stay closed letting no vacuum to the distributor until you shifted to third and completed the electrical curcuit to ground. The switch would open and you'd have vacuum to your distributor.