The TCS switch on my M22 tranny is broken off.Does this really do anything to affect the way the car runs? Thanks guys and Merry Christmas!!

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Dean Ciampi
Team Chevelle Gold #52
Aces #3094 MY LS6 CHEVELLE (http://community-2.webtv.net/SS454chevelle/1970LS6CHEVELLE/)

Dean, sorry dont really have the answer to your question,although i've heard the whole TCS system was really b.s..I too have a ls6 and i was wondering if you had any pic of the lines running off the tcs silinoid on the intake.My car is missing all the TCS items.Don't have much info to go on other than few pics in the magazines i have.Hope everybody has a MERRY CHRISTMAS AND HAPPY NEW YEARS. Ray

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My 70LS6 (http://chevelles.com/showroom/RAY1.JPG)

The TCS was an abbreviation for "Transmission Controlled Spark". A pollution control device that controlled the vacuum advance to the distributor in high gear. I'm not sure if disconnecting it would make any difference performance wise as the vacuum advance is ineffective under load anyway. I would bet it was one of the first or second things to get tossed besides the air pump and hoses back in the day. Glenn

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http://msnhomepages.talkcity.com/yosemitedr/quintillis/index.html

Thanks Glenn.Sorry Ray but at this time I don't have any close up pics.Merry Christmas fellas

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Dean Ciampi
Team Chevelle Gold #52
Aces #3094 MY LS6 CHEVELLE (http://community-2.webtv.net/SS454chevelle/1970LS6CHEVELLE/)

Dean,

That's probably the best thing to happen! Without the switch, the vacuum advance can NOT be "starved" from engine vacuum. You see the tranny switch provides the ground directly to one side of the TCS solenoid. When the gear box is the low gears (all but 4th) the switch is grounded, this provides a ground path to the coil allowing it to energize, when it engergizes, it "robs" the vacuum away from the distributor.

Sooo... Thanks to having this busted, you won't have a ground to the solenoid, thus your distributor's vacuum advance will see vacuum in all gears--the way it should be.

http://www.chevelles.com/forum/smile.gif Don't worry.

P.S. I could type all day on this subject, but I will be attempting a 1970 TCS webpage explaining the full and exact operation of the system, wiring, and vacuum hose connections and lastly troubleshooting in 2001.

Joe

Thanks joe.Glad to hear about that

Coppertop,

If that is the way the TCS system was designed to operate, then why did Chevrolet even incorporate it into the Chevelle, especially the BBCs? You mentioned that distributor advance should be present duing all gears, but the TCS only allows it in 4th gear, I don't get it... http://www.chevelles.com/forum/confused.gif

Super70,

I will cover that in my website. The TCS was apart of the Emissionssystem in 1970. This was undoubtedly a ploy to make the government (who was getting stricter by the month it seemed) smile upon GM. By putting little b.s. that was aimed at pollution control it showed that GM was making attempts at making their engines cleaner burning.

The starvation of engine vacuum in low gears is/was suppose to reduce emmissions out the tail pipe. Now, I really can see nothing that is reduced that much by friggin' vacuum advance! If we have any scientific emmissions people out there--e-mail me! Starving vacuum is not going to make that big of a reduction in emmissions?! If it does, let me know, or I'll stick to my "big brother is watching" assumptions.

Anyone care to add?

Joe

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Creator of Team Chevelle's RADIO TECH (http://www.chevelles.com/radiotech) for original audio questions and answers


Wanted:

-1968 VW beetle water pump

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Actually, the operation of the TCS is exactly opposite of what coppertop describes. It allows for Vacuum advance only in 4th gear, or 3rd in the turbo 400. The switch in the right head with the green wire to it allows for spark advance when the engine is either cold or overheating badly.
This is why I suggested to 260 that he advance his timing a long time ago to make up for the lack of vacuum advance when his car was overheating.
I would either ground the wire and allow vacuum all the time, or bypass the solenoid and just make it look like it works.



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'70 LS6-SOLD
'69 Camaro Indy Pace Car
'68 Elky 396/375 M22
Wanted- '70 GTO Judge!

Thanks Dave!I remember the help you gave me on the overheating problem and you were right on!I am fixing the switch for originality.Thanks guys

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Dean Ciampi
Team Chevelle Gold #52
Aces #3094 MY LS6 CHEVELLE (http://community-2.webtv.net/SS454chevelle/1970LS6CHEVELLE/)

Dave,


HOW AM I WRONG? re-read my post--that's what I said.

I've spent a lot of time discussing this and working with my stock system/diagrams.

The vacuum is robbed when the TCS solenoid is energized This happens in ALL gears BUT "HI".

If you incorrectly connect the hoses on the TCS solenoid, you'll get the opposite effect. The idea was not have the TCS solenoid wear-out under normal driving conditon,--if the car's vacuum advance depended on the electrification of the solenoid, a lot would be riding on that little solenoid/related wiring.

The transmission switch is a N.C. (normally closed switch). The pressure of the fluid in the tranny exerts force on the switch in "HI" gear, causing it to "un-ground", thus the TCS solenoid on the manifold loses its ONLY ground connection, thus power is lost and via vacuum connections the distributor sees the full engine vacuum.



[This message has been edited by Coppertop (edited 01-10-2001).]

Joe-

Sorry for the misunderstanding. After re-reading your post I see that you were correct. It didn't latch on the first couple of times I read it.
As Dean found out, the only thing the TCS system really did was to cause problems.

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'70 LS6-SOLD
'69 Camaro Indy Pace Car
'68 Elky 396/375 M22
Wanted- '70 GTO Judge!

Coppertop

The pressure of the fluid in the tranny exerts force on the switch in "HI" gear, causing it to "un-ground", thus the TCS solenoid on the manifold loses its ONLY ground

I believe Dean's car is an M-22 so the part about pressure does not apply to these transmissions. They rely on a more mechanical action to activate the system.

I always looked on these as sort of a high gear retard, I guess that over simplifies the operation.



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Wally
www.muncie4speed.com (http://www.muncie4speed.com)
Gold #67
2001 Chevy Silverado LT
67 Malibu "Small Block" second owner
90 SS454
71 Malibu "Small Block"

Wally,

Thanks, I always wondered about that, good info. The operation does remain the same though, high gear = ungrounded switch.

The 3/4 gear slector has a notch in it that a ball in the TCS switch rides in until high gear. What I don't know is the open or closed part. I have one of these side covers but none of the shift arms. It would be nice to know the operation of the circuit.

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Wally
www.muncie4speed.com (http://www.muncie4speed.com)
Gold #67
2001 Chevy Silverado LT
67 Malibu "Small Block" second owner
90 SS454
71 Malibu "Small Block"