The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-17-2003, 09:37 AM   #1
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Vacume advance hookup

On my totally stock '71 350 Quadrajet the vacume advance hose runs from the ft. of carb to this electrically controlled idle speed "thingy"........and then to the distributer. Can I just bypass this thing so I get advance during warm up or whenever that "thingy" says I can't? Whats not shown is a vacume hose comming off the top of the "thingy" which is hidden behind a hose in the picture........it goes to the charcoal canister.
Attached Images
 
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 09:39 AM   #2
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
the other end of "thingy"
Attached Images
 
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 09:40 AM   #3
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Yes I know that hose has a crack in it........LOL!
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 09:48 AM   #4
Huck
Senior Member
 
Huck's Avatar
 
Join Date: Jun 2001
Location: Shelbyville, KY
Posts: 3,261
You can run the vac hose direct from the carb to the dist vac advance. Believe that thingy may be for the A/C----Huck
Huck is offline   Reply With Quote
Old 01-17-2003, 09:53 AM   #5
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Thanks, but I don't have a/c. Maybe something for Calif. smog? I don't know.
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 02:14 PM   #6
neonlarry
Registered User
 
neonlarry's Avatar
 
Join Date: Feb 2002
Location: Vacaville, CA
Posts: 2,745
On mine there 2 vaccuum lines coming out of that piece. One goes to the the vaccuum advance, and the other goes to the back of the carb. Does anyone know what that line does? I have looked at diagrams of the q-jet, but I still can't figure it out.
__________________
70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights
99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs
95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI
neonlarry is offline   Reply With Quote
Old 01-17-2003, 04:22 PM   #7
lukecp
Formerly yellow72custom
 
lukecp's Avatar
 
Join Date: May 2001
Location: Austin, TX
Posts: 7,531
I'm also betting that is a California emissions thing. My original Arkansas truck didn't have anything like that when it still had the original 350 in it. It also didn't have a charcoal canister. If you don't have to get the truck inspected by the smog guys, i would be tempted to get rid of the charcoal canister. Maybe you could remove the "thingy" and see how it runs why you are at it........???
__________________
'72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride.
'70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck.
'97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg
lukecp is offline   Reply With Quote
Old 01-17-2003, 06:26 PM   #8
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Thanks guys, I guess I'll just remove that "thingy" since in Ca. pre-1974 dosent have to get inspected anymore.........Yippee!
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 06:57 PM   #9
7T1BURB
Registered User
 
Join Date: Aug 2002
Location: Newport News, VA
Posts: 190
The "thingy" is called the CEC (combination emission control) solenoid vacuum switch which is energized by grounding of the TCS switch at the transmission. "When the solenoid is in the non-energized position, vacuum to the distributor vacuum advance unit is shut off and the distributor is vented to atmosphere through a filter at the at the opposite end of the solenoid. Broken or disconnected electrical electrical connections resulting in failure of the solenoid to function will resuilt in no vacuum advance and no high gear deceleration throttle position."...per Service Manual pg. 6T-3.....have a "thingy" on our bone stock 307 and didn't know what is was or did..took me two months to find out what the "thingy" was and how it operated. If you look on the Driver's side of your transmission, you'll see the electrical lead going to the TCS.....if you need more info on the system operation, let me know and I'll send you the info.......hope this helps. I don't know about "disconnecting"/"bypassing" this solenoid as our engine has not been fired-up yet after rebuild... not a California peculiar system as our Burb was initially a Pennsyvlavia purchased vehicle..

Last edited by 7T1BURB; 01-17-2003 at 07:01 PM.
7T1BURB is offline   Reply With Quote
Old 01-17-2003, 07:22 PM   #10
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Thanks...........that sheds light on the "Thingy". I like "thingy " better than CEC.
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Old 01-17-2003, 11:57 PM   #11
1badz
Registered User
 
Join Date: Jan 2003
Location: S.D.
Posts: 36
7t1burb: I was wondering if you could by pass the vacuum advance altogether and turn up the initial timing from say 8 to around 14 degrees thus causing faster acceleration.which would be caused by no loss of vacuum from the carb under fast and hard acceleration, since there is a slight loss of vacuum just for a split second, and you could then put a cap on the vacuum port on the dist. and the carb.Just wondering if that would help.
1badz is offline   Reply With Quote
Old 01-27-2003, 05:51 PM   #12
Bilgewiper
Registered User
 
Join Date: Dec 2002
Location: Citrus Heights Ca.
Posts: 186
Finally got around to tuneing this thing up and bypassing that CEC (thanks 7T1BURB). Boy did that wake this thing up. I doubt it ever got vacume advance. Thanks again
__________________
Ethan
'71 C-10 LWB Cheyenne 85K miles.

"Time spent Boating is NOT deducted from ones lifespan".
Bilgewiper is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:26 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com