TCS relay?? [Archive] - Chevelle Tech

: TCS relay??


SKOTEEEEE
Sep 15th, 99, 9:57 PM
What is it and what EXACTLY does it do....even the jokers at the Chevy parts counter didnt know,"something to do with smog"...70/396 not built in CA

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Gene McGill
Sep 15th, 99, 10:32 PM
Transmission Controlled Spark.

Basically the tranny tell the solenoid that your in 3rd gear and allows vacuum to be applied to the vacuum advance on the distributer. No vacuum advance in 1st or 2nd.

tom3
Sep 16th, 99, 6:58 AM
If you ride around town a lot you can remove this and get a little better gas mileage and the engine may run cooler. Sometimes it's hard to get the idle speed right with full time vacuum advance though. tom

Bill T SS70
Sep 16th, 99, 8:40 AM
As my fading memory of 29 years ago recalls, when I took delivery of my 70SS the salesman gave me a T connector and showed me where & how to install it to disable the TCS so I had full vacuum advance in all gears.
He told me to make sure I removed it anytime the car returned for service and he knew nothing about the T http://www.chevelles.com/forum/wink.gif

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Bill Taylor
Merrimack, NH
TC Gold Member #73
http://www.chevelles.com/showroom/BillTSS70-2

elcamino72
Sep 16th, 99, 10:54 AM
I have a chiltons manual, 1967-1974 I believe that tells you exactly what it does. Basically Gene is right, but it is a little more compicated than that. I removed the one from my '72 elky, it has a 350. I did't notice any differance in performance or fuel economy.

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Bryan Shook
Burgettstown, Pa
1972 El Camino

Gary S
Sep 16th, 99, 12:32 PM
I have to agree with elcamino72. The TCS solenoid prevents you getting full vacuum advance in any gear but high gear. However, it does give some vacuum advance all the time. (at least, mine does.)
So, at low RPM cruising speed, your engine is not generating any serious HP anyway, so if there is any loss, it cannot be detected.
At wide open throttle down the drag strip, the carb and intake vacuum will already be low on any engine, so again, all engines, with or without TCS will be running limited vacuum.
If it is in your way, you can remove it, and if not, just leave it alone.
The TCS effectively does nothing you can detect. It was one of those feel-good things done back in 1970 to appease the Government.
You notice that it was no longer used in 1971 when emissions started to become an issue.