Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

does timing effect air/fuel ratio?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by zach78k5, Nov 22, 2004.

  1. zach78k5

    zach78k5 1/2 ton status

    Joined:
    May 14, 2000
    Posts:
    406
    Likes Received:
    0
    I assume it would. Could bad timing make my engine run too lean? I have a holley projection and the fuel pressure is plenty high. My rich lean indicator is still reading too lean. Would an intake manifold leak cause this or could the timing be the problem? What else could I adjust?
     
  2. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

    Joined:
    Apr 20, 2004
    Posts:
    12,343
    Likes Received:
    1,047
    Location:
    Northern Colorado
    I'm not sure that timing could cause the problem. I suppose it could be possible that a vacuum leak would cause a lean condition because it would be allowing more air into the mix.

    Could it be a bad sensor somewhere? Not sure what the ProJection uses for sensor inputs. Maybe a bad injector.

    I'm kinda guessing, but maybe someone else will chime in with better ideas.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

    Joined:
    Jul 22, 2001
    Posts:
    16,217
    Likes Received:
    1
    Location:
    Mesa , Arizona USA
    Your right Scott . Air has to be getting in their somewhere AND/OR something is wrong on his system . His computer is supposed to set the AF ratio and the timing advance and retard . The timing doesn't care what mixture it sees on carb motors , and on FI engines static timing is still set on the distributor . The static timing will be set wherever the distributor is dropped at , turned to , and tightened at , advance is mechanical too by springs /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif
     
  4. zach78k5

    zach78k5 1/2 ton status

    Joined:
    May 14, 2000
    Posts:
    406
    Likes Received:
    0
    The timing is independant of the system. The use of the air/fuel ratio monitor is necessary and there are dials on the system to adjust main, idle, >3000rmp, choke and accel fuel delivery. using the monitor device the dials can be adjusted properly. My fuel line is 5/16 instead of 3/8 but my fuel pressure is just over 20 psi and the system requires 15 psi. Would that make a difference? The intake was replaced very recently. The only thing I can think of is a leak on the gasket maybe
     
  5. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

    Joined:
    Apr 20, 2004
    Posts:
    12,343
    Likes Received:
    1,047
    Location:
    Northern Colorado
    Just a thought. Has the fuel pressure always been 20lbs? If your fuel pressure is higher than normal, and your running lean could you have a plugged up injector?

    You know I had a problem with a carb install, because I tightened the carb mounting bolts to 12IN-lbs instead of 12FT-lbs. The motor was running funny because it was getting all that extra air under the carb.
     
  6. zach78k5

    zach78k5 1/2 ton status

    Joined:
    May 14, 2000
    Posts:
    406
    Likes Received:
    0
    I suppose I could try tightening those bolts. I am pretty sure they are torqued pretty tight though
     

Share This Page