Engine rev problem (very weird issue) - 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 12-18-2007, 06:44 PM
Registered User
 
Join Date: Dec 2004
Location: Huntsvile, AL
Age: 40
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Engine rev problem (very weird issue)

Ok, so I got in my '66 Mustang last Friday morning and cranked it up and the engine had this weird idle. It was as if I was stomping my foot on the gas and immediately letting go, like I was trying to rock the car using the engine. Sort of a VOOM ... VOOM ... VOOM. Trying to give it gas sort of calmed the voom ... voom down, but it had a hard time idling. I'm at a loss as to what would cause this and it's tough to explain to people because it's so odd. It's not a gradual rev up above idle, but it's a hard rev. A amateur mechanic friend suggested I try replacing the fuel pump, but I was wondering if anyone here also had any suggestions?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-18-2007, 06:52 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,844
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Maybe your neighbors cat is playing with the linkage? LOL (just kidding)

What carb is on it?

It's possible that the carb is dripping from the nozzles and causing a rise in rpm's. Start it up and let it idle and look down the carb for drips. If it's a Ford 2bbl carb, the power valve may be bad. It's externally accessable from the under side of the bowl, under a small square cover held on with 4 screws.

Mark
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-18-2007, 07:02 PM
Registered User
 
Join Date: Dec 2004
Location: Huntsvile, AL
Age: 40
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
wow, quick response. =)

It has an Edelbrock Performer series 600cfm carburetor with an electric choke that's about 2 or so years old.

I wouldn't really call it a rise in rpms though, it's really as if I was stomping the gas and letting go immediately, but it never revs up enough to call it an idle. I guess it's almost as if it runs for a half-second, then dies, then runs, then dies. I'm sorry I'm having such a hard time explaining what it's doing, but it just so bizzarre.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-18-2007, 07:06 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,844
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
That's a pretty bullet proof carb. What ignition is on it? Could be a condensor problem or ????????? May be time to find an older shop with an old Sun scope that can "see" what the ign is doing.

Maybe a bad torque converter trying to lock up? I dunno! LOL

If you drive it, how does it do? Ok? Surge? anything odd?


Mark
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-18-2007, 07:37 PM
justold's Avatar
Registered User
 
Join Date: Sep 2003
Location: South Jersey
Age: 66
Posts: 192
Wiki Edits: 0

Thanks: 0
Thanked 4 Times in 4 Posts
try disconnecting the vacume advance , if it goes away it is probably a bad pigtail or pickup coil lead
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-18-2007, 08:59 PM
Registered User
 
Join Date: Dec 2004
Location: Huntsvile, AL
Age: 40
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Ok, I disconnected the vacuum advance and the problem entirely went away. Thanks much, justold.

Ok, so, you say it may be a bad pigtail or a coil lead. I'm really an amateur here, can you go into more detail as to what you mean? This is the second issue I've had with the distributor in the past few months. I had to replace the control module in it about a month or so ago. It's a HEI proform distributor from Summit. Blue of course. =)

Oh, also, this is a daily driver. If I plug the advance on the carburetor, can the car be driven until I can get this fixed?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-18-2007, 09:25 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
Yes it's drivable

Quote:
Originally Posted by danbeck
Ok, I disconnected the vacuum advance and the problem entirely went away. Thanks much, justold.

Ok, so, you say it may be a bad pigtail or a coil lead. I'm really an amateur here, can you go into more detail as to what you mean? This is the second issue I've had with the distributor in the past few months. I had to replace the control module in it about a month or so ago. It's a HEI proform distributor from Summit. Blue of course. =)

Oh, also, this is a daily driver. If I plug the advance on the carburetor, can the car be driven until I can get this fixed?
You can drive it. It just won't get quite as good gas milage.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-19-2007, 12:40 PM
justold's Avatar
Registered User
 
Join Date: Sep 2003
Location: South Jersey
Age: 66
Posts: 192
Wiki Edits: 0

Thanks: 0
Thanked 4 Times in 4 Posts
the wire going to the pickup coil inside the distributer is broken in the distributer . the pickup coil moves back and forth when vacuum is applied ,if you take the cap off and pull on the wires one at a time one is going to stretch .you could run without vacuum but it is going to quit on you , but when!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-20-2007, 04:11 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,844
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Justold............GOOD CALL!!! I used to see that alot way back in the day on HEI Pontiacs. I made the wrong assumption that he was still running a points dist.! LOL (kinda dates me huh?)

Mark
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-20-2007, 07:30 PM
Backyard Mechanic
 
Last photo:
Join Date: Jan 2006
Location: Christmas, Florida
Age: 26
Posts: 50
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You know what happens when you assume....you make an *** out of you and me...J/K
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
Engine Identification problem 1984stepside Engine 5 05-27-2008 12:49 PM
New engine smoking problem MYKEEDIX Engine 4 08-27-2007 06:36 PM
Problem, engine RPM "hops" Italy's Finest Engine 3 07-22-2007 04:25 PM
327 engine problem 49dream Hotrodders' Lounge 4 08-14-2004 08:20 PM
engine stuck wheres problem??? atvloco Engine 11 10-07-2002 11:08 AM


All times are GMT -6. The time now is 07:08 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.