small block stumbles - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-06-2003, 04:26 PM
New Member
 
Join Date: Nov 2002
Location: Hot Springs, Ar.
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Unhappy small block stumbles

I have a 400 small block chevy, bored 40 over, a 458 lift cam, edlebrock airgap rpm manifold with a 1407 edlebrock manual choke carb. Ever since I put this all together,(over a year) the engine stumbles to the point of dying if I floor it and don't let off.this will happen off idle. It also stumbles when the vehicle's moving, but recovers before it dies.
I thought I had trash in the carb from some gas I got once that had trash in it enough to dirty 2 fuel filters. I've completely torn down the carb and cleaned it, and even though it didn't look like it needed it I put a new acelerator pump in it. I've moved the rod to the pumps arm up and down in the three holes for adjusting pump stroke. I've also had the timing everywhere you could imagine by advancing the distributer to the point of it making the starter drag to the other end until it backfires back through the carb. I've changed the springs on the curve kit, and adjusted the vacuum advance to so many combos I couldn't even try to list them.
Can someone please give me some suggestions about what might be causing this. something aside from the typical holly fan telling me to get one of them.
Any insight on this will be greatly welcomed, I'm running of of ideas.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-06-2003, 04:42 PM
Gettin a life..Goodbye
 
Last photo:
Join Date: Jun 2003
Location: Bye
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What type if ignition are you running on this setup and are you sure there's enough gas coming into the carb? Manual or electric fuel pump? What type of vehicle is this in?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-06-2003, 04:44 PM
lluciano77's Avatar
Short changed on common sense
 
Last photo:
Join Date: Jun 2003
Location: california
Age: 37
Posts: 3,548
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Set your distributor advance at 18o with 16o initial. If the problem is still there it has to do with carb tuning. Buy a vacuum guage if you don't already have one. Set your mixture for highest manifold vacuum. If that doesn't do it I'd go Holley.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-06-2003, 08:17 PM
New Member
 
Join Date: Nov 2002
Location: Hot Springs, Ar.
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Shortstep, I'm running a GM HEI distributor with a 50,000 volt coil and matching ig mod. It is a manual fuel pump, but it stumbles imediately when I romp on it.there's still plenty of fuel in the accelerator pump. the truck has plenty of pep as long as I don't try to come out at full throdle. It's in an 85 GMC Sierra Classic, SWB. has 373 locking differential rear end.
Illuciano77 I'll be able to manage setting the timing as you've said, I don't know what it is now. Did it by ear and test runs. But as to the mix you're talkin about. I am ignorant about that. Please explane in much more detail. I'm not nearly as experianced as as you and many others here.
Thank you very much.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 10:15 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.