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 10-04-2004, 02:23 AM   #1
Broken_down?
Registered User
 
Join Date: Sep 2003
Location: Oroville, CA ( northern California)
Posts: 466
Highway smoke?

Around town my truck does not smoke or anything, On the highway in the day it does not smoke either. But at night on the highway when I floor it to pass etc it lets out a smoke screen. How can I stop this from happening. It only happens at night when I floor it. I am thinking the only reason I see it at night is because of the head lights behind me. Anyone got any ideas?

Rich
__________________
Quote:
Don't get upset when she marks her territory in the driveway.
Quote:
WHY DO THEY CALL THEM JUNKYARDS ANYWAY??? I LIKE TO THINK OF IT AS A TREASURE HUNTING MISSION
Broken_down? is offline   Reply With Quote
Old 10-04-2004, 06:42 AM   #2
rage'nrat638
Account Suspended
 
rage'nrat638's Avatar
 
Join Date: Mar 2003
Location: ** THE FALL GUY **CHICAGO IL
Posts: 5,883
Thumbs up

sounds like it's running a little rich......it's just unburned fuel......

drop in a 50,000 volt hei.......lean out the idel mixture screws......

have someone drive your truck.....kick it down.....drive there car behind your truck....watch.....ans sniff......you will see.....
rage'nrat638 is offline   Reply With Quote
Old 10-04-2004, 10:37 AM   #3
cduster
Registered User
 
Join Date: Oct 2002
Location: S.W. Michigan
Posts: 403
Sounds like a rich condition to me, too. R'n'R has the right idea, I think.

Dan
cduster is offline   Reply With Quote
Old 10-04-2004, 01:36 PM   #4
Broken_down?
Registered User
 
Join Date: Sep 2003
Location: Oroville, CA ( northern California)
Posts: 466
wow thats a better answer ten I was expecting. Glad to hear it more then likely not the rings I only have the repair manul you get a autozone and it don't tell me the idle mix specs. Can someone suggest so pointers. I am doing all the work by myself and this is my 1st truck. So any help would be great!

:: EDIT::
Does the mixture have anything to do with the dwell spec? Does adjusting the timing effect the mixture? Cause IU was finally able to get the truck to stop pinging going up extremem hills. Hate to have the ping back.


Thanks

Rich
__________________
Quote:
Don't get upset when she marks her territory in the driveway.
Quote:
WHY DO THEY CALL THEM JUNKYARDS ANYWAY??? I LIKE TO THINK OF IT AS A TREASURE HUNTING MISSION

Last edited by Broken_down?; 10-04-2004 at 01:39 PM.
Broken_down? is offline   Reply With Quote
Old 10-04-2004, 03:19 PM   #5
jlmtrout
Registered User
 
Join Date: Jul 2002
Location: Memphis, Tn
Posts: 194
Idle mixture screws affect fuel mixture, dwell is amount of time (in degrees)points are closed. To adjust idle screws, hook up a vaccuum gauge to the carb port that vaccuum hose to dist connects to. Slowly and gently turn the screws in (one at a time) until vaccuum is affected or until screw bottoms out. Then back the screw out until you reach max vaccuum on the gauge. (Repeat process for other screw) You may have to do a little fine tuning once you get both screws close to being right (repeat process without turning screws all the way in). Also you should maintain the same rpm while making adjustments to carb. As the idle speed increases as you adjust the screws, adjust your rpm at the same time to acheive consistant rpm. No, timing does not affect idle mixture. If you can't see the smoke in the daytime, (black or blue) I wouldn't worry about it. Good luck and keep on truckin'....................Jerry
__________________
'68 c-10 long wheelbase fleetside, been in family since new, originally 250 3 speed
Now (389) 350 .060 over 3.75 stroke,Edelbrock Performer RPM 70cc heads and Intake
600 cfm Edelbrock,Small Comp Cams retro-roller cam and roller rockers,9:1 cr, headers, HEI,Old Air a/c, 72 power disc brakes w/stainless lines, 3.42 gear,T-56 6-speed, original paint(what's left of it). Dakota Digital Dash
jlmtrout is offline   Reply With Quote
Old 10-04-2004, 03:37 PM   #6
biglou55
Senior Member
 
Join Date: Sep 2002
Location: Greenfield Mass.
Posts: 551
Talking

actually timing does affect fuel burn. if it is pinging you are not getting your spark at the right time to completly burn your gas. hence a rich mixture. ragenrat is right adjust carb +timing you should be good to go.
__________________
Certifiably crazy person
biglou55 is offline   Reply With Quote
Reply

Bookmarks


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 06:19 PM.


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