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 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-13-2009, 01:57 PM   #1
84step
Registered User
 
Join Date: Jun 2008
Location: Vancouver BC
Posts: 72
Need help! New carb

Hey guys could really use your help/advice on this one. Bare with me iam pretty new to this and this is my first carb swap. heres the deal, a friend of mine and myself replaced my old q-jet with a new Holley 670cfm street avenger. we got it on and somewhat tuned but what i have found is that if i have it i park the idle is fairly high i dont know the exact rpm because i dont have a tach but when it is either reverse or drive it goes down alot and the truck almost dies. It is driveable but when i stop it seems liek it dosent completley go out of gear and i have to hold the brake very hard or it will begin to roll, it also accelerated a little even when i do not have my foot on the gad pedal. Iam stumped so any help or advice would be much appreciated.
__________________
"All Throttle No Bottle"
1984 C10 Stepper
84step is offline   Reply With Quote
Old 04-13-2009, 02:17 PM   #2
J_PEPIN87
Registered User
 
J_PEPIN87's Avatar
 
Join Date: Sep 2008
Location: PASADENA,TX
Posts: 206
Re: Need help! New carb

Double check your vacuum lines make sure they're hooked up on the right port, happened to me once.
J_PEPIN87 is offline   Reply With Quote
Old 04-13-2009, 02:22 PM   #3
85Bowtie
Registered User
 
85Bowtie's Avatar
 
Join Date: Mar 2009
Location: TN
Posts: 410
Re: Need help! New carb

Well, one thing, assuming you don't have a vacuum problem first, is with it in park, turn your idle speed screw out to lower the idle. Then you turn your idle mixture screws outward a 1/4 turn at a time on each side of the carb until your idle comes back up. When your idle speed no longer increases, back off about 1/8 of a turn and you should be there. Then adjust your idle speed screw back up or down until you get the correct idle in park.

Then see how it idles when you go into Drive.

You can hook a vaccum gauge up to your ports and turn the idle mixture screws in and out until you achieve the greatest vacuum if you have the gauge. If not, do it by ear like above.

When you turn one side of the mixture screws, you HAVE to turn the other screw on the other side of the carb the same direction AND the same amount of turn.

Hope this helps.
__________________
'69 Dodge Charger R/T 440, 727, 3.55 Sure Grip
'68 Plymouth Road Runner 383, 727, 3.23 Sure Grip
'89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip
'77 Dodge Monaco ex cop car 440, 727, 2.71
'79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip
'12 Dodge Challenger SRT8 392, M6, 3.92
'85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73

Last edited by 85Bowtie; 04-13-2009 at 02:23 PM.
85Bowtie is offline   Reply With Quote
Old 04-13-2009, 02:25 PM   #4
mrh33916
Project '67 454
 
mrh33916's Avatar
 
Join Date: Jan 2009
Location: Columbia SC
Posts: 283
Re: Need help! New carb

Does it have a electric choke? Did you hook it to the wire that went to the quadrojet carb? I've found that that wire won't work on a Holley, it needs to have 12 volts with the ignition on.
mrh33916 is offline   Reply With Quote
Old 04-13-2009, 02:27 PM   #5
84step
Registered User
 
Join Date: Jun 2008
Location: Vancouver BC
Posts: 72
Re: Need help! New carb

Thanks for the quick responses and ill try them all, Yes it does have a electric choke i did hook it to the same wire, what wire will work then?
__________________
"All Throttle No Bottle"
1984 C10 Stepper
84step is offline   Reply With Quote
Old 04-13-2009, 02:36 PM   #6
mrh33916
Project '67 454
 
mrh33916's Avatar
 
Join Date: Jan 2009
Location: Columbia SC
Posts: 283
Re: Need help! New carb

My neighbor has a '86 and we had the same issue, we ran a new wire to the fuse box. Some people attach it to the distributer wire. You can temporarily run it directly to the + post on your battery to tune the carb. then tackle the new wire later. Did that truck have a computer in it? If so you might want to change out the distributer to a non-computer version.
mrh33916 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 01:22 PM.


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