![]() |
|
![]() |
#1 |
Registered User
Join Date: May 2009
Location: Gonzales, LA
Posts: 779
|
Name that part.....
I'm sure this is an easy one for most of you guys, but what in the world are these things? I've searched with no answer that I could find. This is on my 70. The thing on the firewall looks like some kind of relay, but for what? Best I can tell, there is a red wire that comes from inside the cab and goes to this relay thing. A black wire comes from the 2/3rd gear yoke on the trans (3 speed saginaw) and goes straight to that thing in the second pic. Then there's a blue and a green wire off of the relay thing, the blue is the other wire to the second pic and the green goes to the temp sensor on the therm housing, clear as mud huh. The piece in the second pic has a vac line from under the carb, it's mounted to the intake manifold and it's attached to some apparatus on the exhaust manifold.
![]() ![]()
__________________
1972 Pale Yella 2WD Blazer ..... 350HO/700R4.... '68 Clipped 1970 Original Paint SWB Farm Truck ..... 5.3/4L80.... 2x HRPT Participant |
![]() |
![]() |
![]() |
#2 |
Old member
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
|
![]()
Anti desialing stuff. Early goverment way to get the smog rules on the trucks.
![]() ![]()
__________________
1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 ![]() Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Aug 2010
Location: Edwards, CA
Posts: 7,503
|
Re: Name that part.....
That would be the transmission controlled spark system. Best bet is to take a look in section 6T of the factory service manual for a complete explanation of it's operation. If you don't have the manuals you can download some useable copies at the link in my signature.
__________________
Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID ** Blazer SPID ** Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders ** Do you have a 1972 Plaid Pickup? ** Plaid Blazer ** Plaid Suburban |
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: Aug 2010
Location: Edwards, CA
Posts: 7,503
|
Re: Name that part.....
Actually it has nothing to do with dieseling prevention. It is a spark advance inhibition system. There is also a technician's pocket service publication with some great details if you can find a copy, titled "NEW CHEVROLET EMISSION-CONTROL SYSTEMS" CC-69-12-10.
__________________
Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID ** Blazer SPID ** Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders ** Do you have a 1972 Plaid Pickup? ** Plaid Blazer ** Plaid Suburban |
![]() |
![]() |
![]() |
#5 |
Registered User
Join Date: Apr 2011
Location: Rapid City, SD
Posts: 104
|
Re: Name that part.....
I just asked this same question a couple of months ago? I ended up thinking it has something to do with the emissions? Mine does not have any wired going to it, completely useless! Of course I have a 383 stroker in my truck now, so whatever it was, it is not needed. Here is the link to my question.
http://67-72chevytrucks.com/vboard/s...d.php?t=597270 |
![]() |
![]() |
![]() |
#6 |
Registered User
Join Date: May 2009
Location: Gonzales, LA
Posts: 779
|
Re: Name that part.....
Cool, thanks. It appears mine isn't hooked up right anyway. The vac advance on my distributer is not hooked up to the solenoid, but directly to carb vac. Looks like I've got an engine bay cleanup project on the list. No reason this would hurt anything if it was relocated to the trash can.
__________________
1972 Pale Yella 2WD Blazer ..... 350HO/700R4.... '68 Clipped 1970 Original Paint SWB Farm Truck ..... 5.3/4L80.... 2x HRPT Participant |
![]() |
![]() |
![]() |
#7 | |
The Older Generation
![]() ![]() ![]() Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,515
|
Re: Name that part.....
Quote:
I wouldn't necessarily throw it away. Put it up on the parts board for a few bucks first and see what happens... LockDoc
__________________
Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
|
![]() |
![]() |
![]() |
#8 | |
Registered User
Join Date: Aug 2010
Location: Edwards, CA
Posts: 7,503
|
Re: Name that part.....
Quote:
Really this goes for anybody pulling nice stock bits during a modifed build.
__________________
Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID ** Blazer SPID ** Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders ** Do you have a 1972 Plaid Pickup? ** Plaid Blazer ** Plaid Suburban |
|
![]() |
![]() |
![]() |
#9 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,437
|
Re: Name that part.....
Transmission Controlled Spark, as SS Tim said.
It doesn't allow vacuum advance until the vehicle is in high gear. This also reduces NOX emissions. Yours also appears to have the thermal vacuum switch, which will not allow vacuum advance even in high gear unless the engine coolant is above a predetermined temperature. The engine warms up quicker with no vacuum advance, gets off the choke quicker, meaning higher efficiency. If it works right, it doesn't really affect drivability.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
![]() |
![]() |
![]() |
#10 |
Registered User
Join Date: Oct 2006
Location: Rock Hill, SC
Posts: 421
|
Re: Name that part.....
Thats the presidential advancement inhibitor, do not remove it, it does nothing but cost you more and more money, you will need to repace it every few months and all the data it spouts back at you is erronious at best and in reality it will just basically lie to you... but itll blame its failures on other parts..
__________________
1968 chevy shortbed, Dark Shadow Gray 4 bolt 383 Stroker,Weiand Super Charger, disc brakes, 9 inch, 391 gear, 20" Eagle wheels, muncie 4 speed/ Hurst shifter, 4/7 drop, Hedman midlengths, 3 inch exhaust w/ 2 chamber flows. 1966 Mustang with 306 roller, c-4, 9 inch Detroit locker rear. 1965 Fastback Mustang w/347 stroker, top loader 4spd, 9 inch detroit locker. 1966 Mustang coup, 306 roller, c4, 9 inch. 65 Cobra, 427, T6oo, 9inch, of course. First gen Hayabusa, airbox mod and running 2 exhaust cams.. Zoom Zoom Zoom |
![]() |
![]() |
![]() |
#11 | |
Registered User
![]() Join Date: Apr 2012
Location: Stillwater, Oklahoma
Posts: 874
|
Re: Name that part.....
Quote:
![]() ![]() |
|
![]() |
![]() |
![]() |
#12 | |
RAT1968 '68 Cab/'71 Parts
Join Date: Feb 2002
Location: Coarsegold, CA
Posts: 2,375
|
Re: Name that part.....
Quote:
they all seem to be pretty much the same. If you read the box before you install them, the box almost always says that they add efficiency. But when you put 'em under the hood, you find out it's just more added weight. People that don't like the current part number usually don't always seem to remember the previous recalls and accidents that were caused by the last group of broken OEM parts they sent us. Of course, they are all really the same. No real purpose. And, all just add a lot of cost. And very little value. Like it or not, there's nothing new with the latest castings.
__________________
M17 Coarsegold, CA RAT's shiny now. But always a rat. |
|
![]() |
![]() |
![]() |
#13 | |
Registered User
![]() Join Date: Apr 2012
Location: Stillwater, Oklahoma
Posts: 874
|
Re: Name that part.....
Quote:
|
|
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: May 2009
Location: Gonzales, LA
Posts: 779
|
Re: Name that part.....
Baaahahahahahaha
__________________
1972 Pale Yella 2WD Blazer ..... 350HO/700R4.... '68 Clipped 1970 Original Paint SWB Farm Truck ..... 5.3/4L80.... 2x HRPT Participant |
![]() |
![]() |
![]() |
#15 |
Registered User
Join Date: Feb 2012
Location: Mission Viejo, CA
Posts: 1,856
|
Re: Name that part.....
hahahah. doesnt get political here very often.
|
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: May 2009
Location: Gonzales, LA
Posts: 779
|
Re: Name that part.....
Well damn. U make me want to get it operable.
__________________
1972 Pale Yella 2WD Blazer ..... 350HO/700R4.... '68 Clipped 1970 Original Paint SWB Farm Truck ..... 5.3/4L80.... 2x HRPT Participant |
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Dec 2012
Location: Virginia
Posts: 233
|
Re: Name that part.....
Depending on where he lives could removing it could affect its ability to pass state inspection? Just asking.
|
![]() |
![]() |
![]() |
#18 | |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,437
|
Re: Name that part.....
Quote:
Also, we don't have annual safety inspections like you see in the snow states. Probably should, some of the rolling wrecks I see around would be off the road.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
|
![]() |
![]() |
![]() |
Bookmarks |
|
|