ettev

Is an idle control solenoid the same as a TCS (just different nomenclature)?

Paul Borowski

The idle control solenoid bumped up the idle on A/C cars. The TCS solenoid controlled the vacuum going to the distributor. The automatic cars(at least in '74)were TEMPERATURE CONTROLLED SPARK, where the manual cars were TRANSMISSION CONTROLLED SPARK. This set-up was not the same on all shark years. I think there were a few years where the TCS solenoid doubled as the idle solenoid like some of the early 454 LS5 cars with A/C.

ettev

Paul:

Thanks. So did NON-a/c cars have the Idle Control Solenoid? I've got a '70 350/300 non-a/c that has neither of these items on it. Would mine just have the TCS setup?

Paul Borowski

Non A/C would have no reason for that solenoid, but I'm not sure of all applications. Many A/C four speed cars did not have the idle solenoid even with A/C, just the automatic cars. Cars came with TCS or A.I.R.(smog pump)depending on the emissions that a certain engine produced. It did not matter whether the car had A/C or not. My '74 is a "non-A/C" car, and it still has the TCS set-up. On your car I'm not sure as I do not have a 1970 assembly manual, but other "70" owners here probably do know. You could post this as a "1970" question and see what kind of responses you get.


[Modified by Paul Borowski, 9:55 AM 12/28/2003]

72ls5fla

72 has TCS and idle stop solenoid.

The solenoid on my car is sed to set idle. It does not move higher when AC is turned on.

The TCS solenoid is controled by a switch on 4spd and auto cars on transmission.

TCS is also controled by a relay on fender skirt and thermo switch on passenger side head. when temp is under 70 degree or over 230 - vacuum is sent to distrributor advance regardless of gear engaged in tranny.

Normal range:
Vacuum to distributor is non existent until car is in DRIVE or 4th gear.

TCS and idle stop are bone original in my car ..... good for example of how it works ..

hope this helps some..

Bill

wolvercote

I have 74 L82 with Hurst 4 spd with wiring intact for TCS but looking for part number for TCS switch it plugs into. Appreciate any info. Thanks

7T1vette

Many A/C cars had vacuum controlled diaphragms in the same location as the idle solenoids or TCS units. The concept was that if the engine started to die, vacuum level would drop and the spring loaded diaphragm would release to bump up the throttle linkage. As the engine then began to rev more, the reverse would happen. It was adjustable to that a good idle speed could be set when A/C was running.