Sudden engine stumble - 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 06-14-2008, 07:03 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sudden engine stumble

My 82 Elky with V-6 , 292 with 2bbl manual carb,manual vacumn advance HEI distributor, auto trans was running fine, I made a stop and shut it off, restarted and drove down the street, made a u-turn and on normal acceleration the engine started to stumble badly and now backfires thru the carb. if you rev the engine. I checked the timing, it is right on, but I did notice the timing light flash seemed to miss a beat every so often. Cleaned the carb, adjusted the choke, no better. Any suggestions please? Thanks, Crash

    Advertisement

Last edited by crash; 06-16-2008 at 07:10 AM. Reason: addtional info
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-16-2008, 01:40 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 crash
My 82 Elky with V-6 , 292 with 2bbl manual carb,manual vacumn advance HEI distributor, auto trans was running fine, I made a stop and shut it off, restarted and drove down the street, made a u-turn and on normal acceleration the engine started to stumble badly and now backfires thru the carb. if you rev the engine. I checked the timing, it is right on, but I did notice the timing light flash seemed to miss a beat every so often. Cleaned the carb, adjusted the choke, no better. Any suggestions please? Thanks, Crash
I would look into the distributor - would be my first guess unless you have a air/fuel ratio meter hooked up on your ride. Maybe the vacuum advance is not right? You said that it's firing when an intake valve is open. But - if your motor is running REALLY lean then it would act like that, too.

I've had problems like that before that absolutely drove me crazy - so I installed a air/fuel ratio meter on my headers so I can tell if it's fuel related or not or at least put my troubleshooting better in the ballpark.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-16-2008, 03:21 PM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
That U-turn may have dislodged some water in the bottom of the tank.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-16-2008, 05:27 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sudden Engine stumble

I have a feeling its in the coil, or distributor, due to the occasional skip of the timing light.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-16-2008, 08:27 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 crash
I have a feeling its in the coil, or distributor, due to the occasional skip of the timing light.
Let us know when you fix it, ok? Good luck.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-16-2008, 08:32 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sudden engine stumble

No luck so far. Thanks
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-16-2008, 09:25 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 58
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Check your fuel supply hose from the tank to the fuel pump for cracks. If it is running too lean from the fuel pump sucking some air, it will miss fire. If that hose is now split enough to suck air, check your engine and transmission mounts for ripping.

Since you made a stop for a little while, then restarted, I would do a compression test, to determine whether it has a stuck valve, or not.

Either one of these are viable problems for your drive ability description.

Stephen
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-16-2008, 09:56 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks I'll check both things, Crash
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-16-2008, 10:24 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 carsavvycook
Check your fuel supply hose from the tank to the fuel pump for cracks. If it is running too lean from the fuel pump sucking some air, it will miss fire. If that hose is now split enough to suck air, check your engine and transmission mounts for ripping.

Since you made a stop for a little while, then restarted, I would do a compression test, to determine whether it has a stuck valve, or not.

Either one of these are viable problems for your drive ability description.

Stephen
What about removing both valve covers and using a remote starter/hand cranking the motor to check for a stuck valve?

But - a compression check would be good, too - it lets you know where you stand.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 06-16-2008, 10:41 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 58
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by Sixtyninemercury
What about removing both valve covers and using a remote starter/hand cranking the motor to check for a stuck valve?

But - a compression check would be good, too - it lets you know where you stand.
You could check for one by hand cranking, but if it is sticking, and not stuck you won't find it. The compression test should be done with the engine hot.

Let me also note: Bad gas will cause this every time. Right now I am battling with a dyno shop (to be named later) over a possible case of "bad gas" right now. (my Avatar)
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 06-17-2008, 02:00 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Engine stumble

It may be a coincedence but my Sunoco station has just switched to a 10% Ethenol mix ? I'm wondering if this is the problem or if in the switch water may have gotten in their tanks?

As soon as it stops raining I will have a lot of things to check to straighten this out.

Just in case I have put a bottle of dry gas in the fuel tank.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 06-17-2008, 03:29 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 crash
It may be a coincedence but my Sunoco station has just switched to a 10% Ethenol mix ? I'm wondering if this is the problem or if in the switch water may have gotten in their tanks?

As soon as it stops raining I will have a lot of things to check to straighten this out.

Just in case I have put a bottle of dry gas in the fuel tank.
Years ago - for what it's worth - I was having similar problems like that. I kept chasing bad gas and the like. I even went so far as to re-plumb the fuel line so that I could have the fuel pump pull fuel from a 5 gallon fuel tank that had known good fuel. It turned out the ignition wiring in my '69 Merc needed to be replaced. . .
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 06-17-2008, 04:20 PM
Registered User
 
Last photo:
Join Date: Mar 2002
Location: Lake Worth, FL
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sudden stumble

Thanks, Yeah, I'll have my hands full with this one.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 06-17-2008, 05:14 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 58
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by crash
Thanks, Yeah, I'll have my hands full with this one.
You bet you will. With that new reformulated fuel your are running now, you will need to check all of your tune-up related parts, and adjustments.
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
the history of chevy v8's savman1 Hotrodders' Lounge 43 03-02-2012 07:57 PM
1973 Chevelle Malibu Engine Rebuild (pics 56k no) Malibu73 Hotrodders' Lounge 39 11-04-2008 01:37 PM
Build for Hp or Torque? Venturat Engine 76 09-23-2008 11:22 AM
Why high RPM's on the oval tack? steveyb4342 Engine 25 05-23-2007 08:50 AM
What would cause engine to stumble and die? trapperjack Engine 4 11-02-2006 08:53 PM


All times are GMT -6. The time now is 04:23 PM.


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.