Author Topic: Mysterious dead spot  (Read 671 times)

Offline Robhimselfff

  • Jr. Member
  • **
  • Posts: 3
Mysterious dead spot
« on: January 14, 2013 - 10:44:51 AM »
So this has been a problem with the car since before I recently put it back on the road this past June.  Under load the car always has the strangest dead spot in the throttle, and in order not to stall out the car  you have to feather your way past it.  It's something I've gotten used to but with the dead spot there's no way you could put it to the floor from a stop or slow roll without it stalling out.  It's a 318 car with an automatic.  The carb has been rebuilt on the car twice since June to try to troubleshoot the problem, but I really have no idea what else it could be.




Offline 4 speed fish

  • Full Member
  • ***
  • Posts: 849
Re: Mysterious dead spot
« Reply #1 on: January 14, 2013 - 11:09:56 AM »
A friend of mine had the same issue.It was the distributor.

Offline 72cudamaan

  • Resident
  • *****
  • Posts: 3248
Re: Mysterious dead spot
« Reply #2 on: January 14, 2013 - 01:08:43 PM »
What kind of carb?, engine mods?  First guess is accelerator pump but you didn't give a whole lot of info.
« Last Edit: January 15, 2013 - 08:47:02 AM by 72cudamaan »
If I cant fix it, it's broke
 
Andy  (phukker whither)

Offline MEK-Dangerfield

  • C-C.com Expert
  • ********
  • Posts: 20946
  • I don't get NO respect! Member since 1/25/2002
Re: Mysterious dead spot
« Reply #3 on: January 14, 2013 - 03:26:26 PM »
Is this a vacuum secondary or a mechanical secondary carb?   

Mike

1970 Challenger - SOLD
2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

Offline jimynick

  • Resident
  • *****
  • Posts: 4512
Re: Mysterious dead spot
« Reply #4 on: January 14, 2013 - 11:00:01 PM »
It may not even be a 4bbl. The off-idle stumble sounds like poor accelerator pumping and regardless how many times the carb was rebuilt, put on some safety glasses, start it up, take off the air cleaner and with a good light, watch for a good strong squirt when you wack the throttle. Check the timing while you're at it. By the by, what kind of carb IS it?

Offline 73restomod

  • Full Member
  • ***
  • Posts: 528
Re: Mysterious dead spot
« Reply #5 on: January 15, 2013 - 01:36:42 AM »
Also, does the trans go thru the gears normally? May seem like an odd question, but it narrows the list of suspects. It could be more than one problem exasperating the carb/timing issues is all.

Sent from my DROID RAZR using Tapatalk 2


Offline cudabob496

  • Sr. Resident
  • ******
  • Posts: 8024
Re: Mysterious dead spot
« Reply #6 on: January 15, 2013 - 04:11:09 AM »
borrow friends carb
if problem still persists, then its not the carb.
but agree, squirters are first thing to look at.

oh, just remembered, my cuda did that under acceleration, turned out
primary jets were too small, and engine was running out of gas, until
secondaries kicked in.
« Last Edit: January 15, 2013 - 04:14:33 AM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Super Blue 72

  • Permanent Resident
  • *******
  • Posts: 12711
  • "Big 'n Little" Member since 8/9/05
    • Phil's Super Blue '72
Re: Mysterious dead spot
« Reply #7 on: January 15, 2013 - 09:13:44 AM »
 :iagree:  Not sure where the dead spot is but if it's off idle like jimmynick mentioned I would guess accelerator pump first. 

When does the dead spot happen exactly?  :clueless:

Also, is this something that just happened while the same carb was on engine?  Is it a new/different carb on the engine? Is the choke open all the way?
1972 Dodge Challenger Rallye 340, AT, Code TB3=Super Blue, SBD=8/17/1971.  Yes, a Rallye without the fender louvers from the factory because of the body side molding option.

Pic #2 and 3 of my ARII 1/24 scale model car 

Phil in New England-Massachusetts  Always thank God for what you have!

http://www.cardomain.com/ride/456046/1972-dodge-challenger

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: Mysterious dead spot
« Reply #8 on: January 15, 2013 - 08:23:08 PM »
Could be springs in the centrifiugal weights .
 Float level as well as a number of other transistional problems can occur as the throttle is opened

Challenger - You`ll wish You Hadn`t