TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

timing jumps 6-8 degrees during base timing setting

Thread Tools
 
Search this Thread
 
Old 04-07-2016, 07:54 AM
  #1  
Junior Member
Thread Starter
 
jjjosh's Avatar
 
Join Date: Apr 2009
Location: reidsville nc
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
Car: 92 B4C/91 Z28
Engine: 5.0/5.7
Transmission: 5 SPD/700R4
Axle/Gears: 3.42/3.23
timing jumps 6-8 degrees during base timing setting

I understand how to set the base timing,, unhook tan wire,,, have 95 454 im setting and while i was setting the timing to 4 degrees,the engine wanted to stumble a lil and i reved the motor some and noticed the timing mark on balancer jump from 4 degrees btdc to 10 -13 degrees btdc,, i know motor should be a idle during timing, but the engine doesnt rev more than 300-400 rps before it jumps 6-8 degrees.. is this normal for the timing to jump that much during base timing setting, or is there other issues going on?? Distributor is from a working engine that had no problems running,,
Old 04-07-2016, 08:15 AM
  #2  
Member
iTrader: (1)
 
2012sergen11's Avatar
 
Join Date: Apr 2013
Location: Ohio
Posts: 372
Likes: 0
Received 0 Likes on 0 Posts
Car: 1987 Trans Am
Engine: 305 TPI
Re: timing jumps 6-8 degrees during base timing setting

Silly question but someone will ask so i'll be the guy , did you have the dizzy tightened all they way down when you reved the throttle?
Old 04-07-2016, 08:28 AM
  #3  
Junior Member
Thread Starter
 
jjjosh's Avatar
 
Join Date: Apr 2009
Location: reidsville nc
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
Car: 92 B4C/91 Z28
Engine: 5.0/5.7
Transmission: 5 SPD/700R4
Axle/Gears: 3.42/3.23
Re: timing jumps 6-8 degrees during base timing setting

Originally Posted by 2012sergen11
Silly question but someone will ask so i'll be the guy , did you have the dizzy tightened all they way down when you reved the throttle?
Of course ,,the distributor was just movable enough by hand to adjust timing and everything else was in location and tight..
Old 04-07-2016, 10:38 AM
  #4  
Moderator

iTrader: (1)
 
RBob's Avatar
 
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,432
Likes: 0
Received 225 Likes on 211 Posts
Car: check
Engine: check
Transmission: check
Re: timing jumps 6-8 degrees during base timing setting

Called limp mode advance. Usually comes in at a higher RPM, such as 1400 - 1600 RPM. Maybe that year BBC GM has it coming in sooner.

RBob.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Abubaca
Tech / General Engine
28
12-16-2020 01:02 PM
BG1959
Engine/Drivetrain/Suspension Wanted
7
07-20-2016 02:22 PM
tognabologna87
Tech / General Engine
10
03-24-2016 04:41 AM
chllnqtp99
TPI
0
03-16-2016 08:03 PM
bbernardo94
Tech / General Engine
4
03-13-2016 09:07 PM



Quick Reply: timing jumps 6-8 degrees during base timing setting



All times are GMT -5. The time now is 09:45 AM.