383 Hesitation - 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 06-30-2008, 06:46 PM
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Baldwinsville
Posts: 202
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
383 Hesitation

I have a 87 Monte Carlo with a 76 383. It has Edelbrock RPM intake, holley 650, comp cams 268h, speed pro flat top hypers, 882 heads (i know they suck), 9.4:1 comp, TH350, B&M Torquemaster 2500 stall, 8.2 3.73 rear end.

Anyway, i have had this problem since i built it. At about 1700-2000 rpm when i slowly press the gas (as not just punching it all the way to WOT) it hesistates and then picks up and goes. It basically sounds like your clearing your throat, huh.... uhhh. It also has a small hesitation at idle at the same rpm's so it not to do with the drive train or load on the engine. I have the timing at 14* initial and 34* total. So i thought it was the shooter nozzles either blocked or too small so i got a set of 31's and put it in, no difference. Then i went to a 35 and still none. Then i figured it was timing so i tried to advance it a little and at first it got a little better, and then as i advanced it more it got worse. So it was a little better but not right. The distributor is a GM HEI 65k. Then i got to thinkin that maybe the secondaries are not kickin in soon enough or maybe too soon.

This is buggin the hell out of me and ive been tryin to get it sorted out for like two months now, at least. Sometimes the car will stall if i ease into a linelock. It seems like the car only wants WOT. Any ideas?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-30-2008, 06:56 PM
Registered User
 
Join Date: Apr 2008
Location: SoCal
Age: 45
Posts: 213
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by mightycarlo10
I have a 87 Monte Carlo with a 76 383. It has Edelbrock RPM intake, holley 650, comp cams 268h, speed pro flat top hypers, 882 heads (i know they suck), 9.4:1 comp, TH350, B&M Torquemaster 2500 stall, 8.2 3.73 rear end.

Anyway, i have had this problem since i built it. At about 1700-2000 rpm when i slowly press the gas (as not just punching it all the way to WOT) it hesistates and then picks up and goes. It basically sounds like your clearing your throat, huh.... uhhh. It also has a small hesitation at idle at the same rpm's so it not to do with the drive train or load on the engine. I have the timing at 14* initial and 34* total. So i thought it was the shooter nozzles either blocked or too small so i got a set of 31's and put it in, no difference. Then i went to a 35 and still none. Then i figured it was timing so i tried to advance it a little and at first it got a little better, and then as i advanced it more it got worse. So it was a little better but not right. The distributor is a GM HEI 65k. Then i got to thinkin that maybe the secondaries are not kickin in soon enough or maybe too soon.

This is buggin the hell out of me and ive been tryin to get it sorted out for like two months now, at least. Sometimes the car will stall if i ease into a linelock. It seems like the car only wants WOT. Any ideas?
My first guess is to verify that your fuel bowl float levels are set at the right spot. Also - verify by manually giving the carb a little bit of gas - do the shooters immediately spray fuel?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-30-2008, 06:59 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 13,283
Wiki Edits: 326

Thanks: 829
Thanked 1,143 Times in 942 Posts
What's the manifold vacuum with the motor warmed up at idle and the trans in gear?

Last edited by techinspector1; 07-01-2008 at 02:46 AM.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-01-2008, 05:22 PM
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Baldwinsville
Posts: 202
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
That was one thing i did check that the fuel bowls are right below the eyesight and the shooters are shooting properly. I also adjusted the pump arm. I'm not sure about the vacuum though.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-01-2008, 06:52 PM
Registered User
 
Join Date: Apr 2008
Location: SoCal
Age: 45
Posts: 213
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by mightycarlo10
That was one thing i did check that the fuel bowls are right below the eyesight and the shooters are shooting properly. I also adjusted the pump arm. I'm not sure about the vacuum though.
Buy a $20 vacuum gauge attached to a manifold vacuum source and have a buddy put it in gear while holding the brakes - tell us your vacuum reading while in gear and not in gear, ok?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-01-2008, 07:16 PM
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Baldwinsville
Posts: 202
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I will do.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-01-2008, 07:34 PM
automotive breath's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: New Orleans
Posts: 891
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
On of the first places I look when working on a bog is ignition advance. If
you have the total advance set for best torque, sometimes you must limit the
centrifugal and add more initial and the bog goes away.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-01-2008, 08:01 PM
Registered User
 
Last photo:
Join Date: May 2008
Location: ohio
Posts: 1,577
Wiki Edits: 0

Thanks: 48
Thanked 63 Times in 60 Posts
Well join the club. I had three different engines with three different cams and three different carbs and they all had the off idle stumble. The worst was with a holly. Your holly will work I am sure. I currently have even worse problems since I have went to a roller cam I have problems with my truck will idle fine but once its poped into gear if your not putting your foot on the gas pedal it will start to studer then quit. I will have to give quickfuel to sort mine out but someone did tell me to see if your off idle stumble if a lean or rich stumble and adjust your squirter. If that does not work you will have to try a lot of other things. Good luck hope you get the kinks worked out.
Eric
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 07-02-2008, 02:15 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
mightycarlo10, There is a chance your accelerator pump is not setup right. You have to check where the plastic cam is set #1 or #2 setting. Set the cam to #2 and make sure there is no slack on the lever. Also you can get the plastic cam kit. Try to select the cam that will work for you. I found out the blue cam works the best at #2 setting. Hope this help
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-11-2008, 07:06 PM
Registered User
 
Join Date: Aug 2008
Location: LA
Posts: 76
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You could try these 12Holley accelerator pump cams . I had that problem but I gave up and switched to Edelbrock.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-11-2008, 07:22 PM
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Baldwinsville
Posts: 202
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I think i know what my problem is. Does that little plastic thing sit in between the arm that goes to the accelerator pump and the actual throttle lever? Because if so thats it. I bought this carb from a friend and it has a spring that attaches that arm and throttle lever.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 08-11-2008, 07:32 PM
Registered User
 
Join Date: Aug 2008
Location: LA
Posts: 76
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The little plastic cam should go on the same shaft the primary butterflies are on.. the shaft that all the throttle linkage is attached to (right behind the throttle linkage on the shaft, its probably hard to see). The spring between the 2 lever arms for the pump is adjustable to take the slack out of the linkage.. slack/ sloppy is bad. Stock gap is about .012 if you have feeler gauges. the cams control how much and how fast the accelerator pump works.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 08-11-2008, 08:11 PM
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Baldwinsville
Posts: 202
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I know about the slack adjuster spring. But on mine theres another spring. I think somebody just used it as a return spring. I did see the cam so i'll have to do some tinkering on that. Thanks
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ok, here's the debate of the century: 383 or 400 chevy!! Cast your vote and reason killerformula Engine 303 03-28-2013 09:08 PM
Supercharging and fuel injecting a 383 Chevy Noesis Engine 11 09-21-2007 06:51 AM
Hesitation! frankenvette Engine 17 05-18-2006 05:55 PM
383 0r 406??? Zubair Engine 60 10-14-2005 08:53 PM
What makes a 383 so much more expensive? Chevy21 Engine 12 09-30-2004 09:55 PM


All times are GMT -6. The time now is 04:41 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.