Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Engine slightly bucking under light load

Thread Tools
 
Search this Thread
 
Old 06-17-2012, 12:53 PM
  #1  
Supreme Member
Thread Starter
 
built91Z28's Avatar
 
Join Date: Feb 2010
Location: Orlando
Posts: 1,446
Likes: 0
Received 2 Likes on 2 Posts
Car: 1991 Camaro Z28
Engine: 357, Canfield heads, solid roller,
Transmission: Upgraded 03 Cobra T56
Axle/Gears: 9" 3.50 gears and Detroit Locker
Engine slightly bucking under light load

I've noticed that while cruising at a constant speed the engine has a very slight hesitation or buck to it. If I press the throttle down just the slightest amount, it goes away. I did notice that after using all the Mobil gas in the tank and filling with Citgo gas it got much better.

Motor is a 350 sbc, 650 mighty demon carb, Canfield heads, 20 degrees initial timing, 35 total, 10 degrees vacuum advance. Primary jets are 72's. To cruise at 50 at 1500 rpm I'm barely on the throttle. Its little enough that how the idle is tuned affects how it drives.
Old 06-17-2012, 01:35 PM
  #2  
Member

iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Engine slightly bucking under light load

you probably have too much timing advance. Mine did the same thing so i retarded the timing a few degrees and it went away
Old 06-17-2012, 04:00 PM
  #3  
Supreme Member
Thread Starter
 
built91Z28's Avatar
 
Join Date: Feb 2010
Location: Orlando
Posts: 1,446
Likes: 0
Received 2 Likes on 2 Posts
Car: 1991 Camaro Z28
Engine: 357, Canfield heads, solid roller,
Transmission: Upgraded 03 Cobra T56
Axle/Gears: 9" 3.50 gears and Detroit Locker
Re: Engine slightly bucking under light load

Thanks. I'll try taking 5 degrees of vacuum advance out of it.
Old 06-17-2012, 04:04 PM
  #4  
Supreme Member

iTrader: (8)
 
TTOP350's Avatar
 
Join Date: Oct 2001
Location: Il
Posts: 11,695
Received 747 Likes on 506 Posts
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Engine slightly bucking under light load

How old are your plug wires? Make sure they are all good and not burnd or arcing to ground.
Old 06-17-2012, 04:05 PM
  #5  
Supreme Member

iTrader: (2)
 
sailtexas186548's Avatar
 
Join Date: Oct 2007
Location: Kemah, Tx
Posts: 2,604
Received 6 Likes on 5 Posts
Car: 1991 z28
Engine: Turbo 310
Transmission: T56
Axle/Gears: D44
Re: Engine slightly bucking under light load

my car w/ a 6-speed does it too, your most likely just lugging the motor
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
theshackle
Tech / General Engine
4
09-17-2020 08:26 AM
CarGuyDennis
Organized Drag Racing and Autocross
137
12-06-2016 11:02 PM
bradleydeanuhl
DFI and ECM
4
08-12-2015 11:48 AM
Omega
Interior Parts for Sale
2
08-10-2015 12:46 PM



Quick Reply: Engine slightly bucking under light load



All times are GMT -5. The time now is 12:13 PM.