What's this crap on my TCS solenoid?
06-25-2004, 11:45 PM
#1
Burning Brakes
Thread Starter
What's this crap on my TCS solenoid?
Friends,
Check out this pic and tell me what's going on.
This is my TCS solenoid - the thing that controls vacuum advance based on engine temps, if I understand everything correctly.
I've got a 1974 LS4 automatic. Since I've had the car, this thing has been bypassed - the ported vacuum hooked directly to the advance cannister. I want to get the correct hoses from the good Doctor and get everything working the way it should.
But, I can't see how this thing is supposed to hold vacuum. So I took a closer look at this thing and noticed the light brown gum-looking crap on the side that goes to the vacuum cannister. Maybe it's some sort of caulk or glue? Maybe someone tried to T a vacuum line into this at one point? Or maybe the fitting is busted and this is an epoxy fix?
I can blow through the side by the electrical connection, and it blows out the hole where this glue/gum crap is. As it sits mounted on the engine, the glue/gum hole faces forward.
With the key on - car not running, engine cold - I don't get anything through the "real" fitting - the green one - where the vacuum advance should hook up. Should I be testing this with the engine warm? I suppose so if it's supposed to limit advance while cold or too hot, right? I'm not getting any voltage to the electrical connector - engine cold, ignition on, car not running. Can I apply 12 volts to it and make it work without destroying it? After all, this is my "numbers matching" TCS solenoid I'm working on here.
Let me know your thoughts. Thanks, GM
Check out this pic and tell me what's going on.
This is my TCS solenoid - the thing that controls vacuum advance based on engine temps, if I understand everything correctly.
I've got a 1974 LS4 automatic. Since I've had the car, this thing has been bypassed - the ported vacuum hooked directly to the advance cannister. I want to get the correct hoses from the good Doctor and get everything working the way it should.
But, I can't see how this thing is supposed to hold vacuum. So I took a closer look at this thing and noticed the light brown gum-looking crap on the side that goes to the vacuum cannister. Maybe it's some sort of caulk or glue? Maybe someone tried to T a vacuum line into this at one point? Or maybe the fitting is busted and this is an epoxy fix?
I can blow through the side by the electrical connection, and it blows out the hole where this glue/gum crap is. As it sits mounted on the engine, the glue/gum hole faces forward.
With the key on - car not running, engine cold - I don't get anything through the "real" fitting - the green one - where the vacuum advance should hook up. Should I be testing this with the engine warm? I suppose so if it's supposed to limit advance while cold or too hot, right? I'm not getting any voltage to the electrical connector - engine cold, ignition on, car not running. Can I apply 12 volts to it and make it work without destroying it? After all, this is my "numbers matching" TCS solenoid I'm working on here.
Let me know your thoughts. Thanks, GM
06-26-2004, 12:55 AM
#2
Instructor
Member Since: Mar 2002
Location: MO
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Re: What's this crap on my TCS solenoid? (mayberg)
Somebody tried to bubba a fitting back on. Should be another fitting off the side where the yellow crap is. Here is what it should look like here http://www.wiringharness.com/images/parts/01114434.jpg. Looks to be about a $80 replacement part. I'm no expert but I thought the solenoid eliminated vacuum advance when your in high gear to make combustion hotter and burn all those nasty pollutants better? Not sure how you test functionality? Nice car, by the way!
[Modified by kermit1654, 12:39 AM 6/26/2004]
[Modified by kermit1654, 9:42 AM 6/26/2004]
[Modified by kermit1654, 12:39 AM 6/26/2004]
[Modified by kermit1654, 9:42 AM 6/26/2004]
06-26-2004, 01:38 AM
#3
Racer
Member Since: Feb 2004
Location: Athol NY
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Re: What's this crap on my TCS solenoid? (kermit1654)
Actually, on '73-74 auto, it allows FULL manifold vaccum to distributor when engine is below 93 degrees or above 232. Then solenoid is energized. When in between those temps., solenoid is de-energized, allowing "ported" vaccum to distributor. On these cars it's actually called "thermo-override system." Standard shifts, and other years, use time relays and transmission switches as well as the temp switch to control distributor vaccum advance. Hence, "transmission controlled spark" 
