1974 pontiac transam

T

tom3901

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This car came from California.I can not figure out what this valve solenoid is for. No place to hook up outgoing vacuum lines. Has a power connector to it. also further up the same wire harness I have another electrical connector. I can find anything anywhere on this...Unsure if perhaps a california car without the air pump now this hView attachment 547as been negated...Please any help...thanks
 
Could be the TCS solenoid (Transmission Controlled Spark). The vacuum advance on the distributor would be connected to this and you would only have advance when the transmission was in high gear, 3rd for an automatic, 4th for manual.
 
That generation, carburetor, would use a solenoid attached to the front of the quadrajet that would extend to push the throttle open when A/C kicked in but not all cars had it.
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melsg5 said:
Could be the TCS solenoid (Transmission Controlled Spark). The vacuum advance on the distributor would be connected to this and you would only have advance when the transmission was in high gear, 3rd for an automatic, 4th for manual.
Click to expand...

Thanks...I think that is it.....
 
I'm going with AC idle, However, i have a 1970 chevy BB pickup (with AC) which also had one. I never fully knew where it hooked up either, however i remember at one point thinking it went to the air cleaner and controlled the air by-pass deal that directed air from outside or hot air from the foil pipe that leads to the exhaust. also interested if anyone finds out what it really did...
 
"nightroddersp;52043]could it posibly goto the flapper valve on the air duct for the air cleaner??? just an idea..."


Yea, that's what i was also thinking, just didn't know what to call it
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I guess the best way to resolve this is for the OP to trace the wire harness connected to the part, hopefully he will let all of us know what he finds
 
I think i found the answer. I believe it is a TCS solenoid (trans controlled spark) Also heard it called a trans vaccum switch. It controlled vac advance depending on what gear the trans was in.
 
68FireBird400:
Isnt that what I said in the second post above?
 
"melsg5;52113]68FireBird400: Isnt that what I said in the second post above?"

Melsg5, yes you did. Not trying to tick you off, there just still seemed to be some confusion. Anyone interested see attached drawing.
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No problem, just thought you missed it, thanks.
 
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