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.

Need Help with my 305

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by JimmyJuneau, Nov 16, 2001.

  1. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    I have been on here the last couple of weeks trying to get info on fixing my truck. I have done what has been suggested to me but I cant get it to run the way it should. I NEED HELP!

    I have a 1985 Jimmy with a 305 and a stock Qjet I rebuilt the qjet put new plugs wires cap and rotor on and it hasnt helped it. The problem is that it is bogging down and stalling out on me.Sometimes I can get it to run perfect ecept it is stuck on a high idle at the time. The truck blow s out allot of black smoke and I was getting only 3 miles to the gallon. Any suggestions would be greatfully helpful to me.

    1985 GMC JIMMY
     
  2. 55Willy

    55Willy 3/4 ton status

    Joined:
    Jun 2, 2001
    Posts:
    9,946
    Likes Received:
    0
    Location:
    Keizer, Or
    Throw a timing light on it and then adjust the idle from there.

    <font color=red>Life is like a mud hole:</font color=red><font color=blue>
    When the S#!T gets deep, you have to keep moving and friends can always pull you out</font color=blue>
    55 Willy's
     
  3. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    I Have never adjusted the timing How do I do it?

    1985 GMC JIMMY
     
  4. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

    Joined:
    Sep 17, 2001
    Posts:
    1,962
    Likes Received:
    0
    Location:
    Western CO
    get a chiltons manual total care care one , it says in there , u need an inductive timing light and a distributor wrench , uhook the vacuum line at the dist and plug it golf tees work fothat , then check it with the light , there are timing marks on a tab on the timing cover and there is a groove in the harmonic balancer , ..i think thats it ....and set it to what it says on the sticker on the cowl or the book



    dents ....
    O R D's axles
    NO BREAKAGE :)
     
  5. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    Okay where is he iming indicator on the engien block located I found the one on the pulley.



    1985 GMC JIMMY
     
  6. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

    Joined:
    Sep 17, 2001
    Posts:
    1,962
    Likes Received:
    0
    Location:
    Western CO
    behind the awa pump



    dents ....
    O R D's axles
    NO BREAKAGE :)
     
  7. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    WHATS THE AWA PUMP BY CHANCE IS THE INDICATOR A BOLT ON ITEM ?

    1985 GMC JIMMY
     
  8. riz

    riz 3/4 ton status

    Joined:
    Mar 7, 2000
    Posts:
    6,026
    Likes Received:
    0
    Location:
    Wisconsin
    <font color=purple> I don't know about you guys but you've both got me confused as hell with youre posts !

    L8r,
    . Riz . <a target="_blank" href=http://www.geocities.com/rizmonkey>www.geocities.com/rizmonkey</a>

    <font color=purple> BOW CHICKA BOW WOW !
     
  9. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

    Joined:
    Sep 17, 2001
    Posts:
    1,962
    Likes Received:
    0
    Location:
    Western CO
    sorry .... behined the water pump , it is a tab with a serrated edge o 4 6 8 on it hard to describe ... the goove on the balancer lines up with the marks on it tell you the advance or retard of your timing



    dents ....
    O R D's axles
    NO BREAKAGE :)
     
  10. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

    Joined:
    Sep 17, 2001
    Posts:
    1,962
    Likes Received:
    0
    Location:
    Western CO
    sorry .... behined the water pump , it is a tab with a serrated edge owith these numbers on it 4 6 8 on it hard to describe ... the goove on the balancer lines up with the marks on it tell you the advance or retard of your timing



    dents ....
    O R D's axles
    NO BREAKAGE :)
     
  11. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    is it on the top of the water pump?

    1985 GMC JIMMY
     
  12. scavenger

    scavenger 1/2 ton status

    Joined:
    Mar 31, 2000
    Posts:
    111
    Likes Received:
    0
    Location:
    Southern Wisconsin
    As far as blowing black smoke, it may be that your choke is out of adjustment or the choke itself is defective. I also have an 85 with the 305, and last year mine started running rough and bellowing black smoke. I removed the plugs and found that they were all carboned up. I then noticed that the wire that plugs into the choke had came off because the plastic connecter cracked. After repairing the choke wire and replacing the carboned up plugs, the 305 purred.
     
  13. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    Well thats the other thing I know isnt working is the choke however I cant seem to trace the wire that leaves the choke on the carb back to wherever it goes do you know where it goes? Would I be ale to jsut get a new choke wire set up and run it into the cab and hook it up to the fuse box or is there more to it then just that.
    Thanks
    Brian

    1985 GMC JIMMY
     
  14. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,173
    Likes Received:
    1,384
    Location:
    E-town baby!
    The timing tab is within 1/2" of the balancer. If you take a flashlight and check the top 1/3 of the balancer you'll find it. I think it's spot welded to the timing cover and there should be line of sight from the topside either from the passenger side or the drivers side. When you find it it will make sense. Take some white paint and mark the little groove in the balancer. Clean the timing tab so the numbers are easier to see as well.

    All that being said it sounds like you still have a carb problem. I suspect the float is either set to high or the needle is sticking causing the flooding and black smoke. Also check to make sure the choke is opening as the motor warms up. From dead cold it should begin to open almost immediately. When the motor is completely warm the choke should be wide open. If it doesn't do that then check the choke linkages for any binding. If the linkage checks out the choke can be adjusted.
    On the passenger side of the carb there is the choke housing...it is held on with either three small screws or three rivets. Hope you have screws...
    Assuming you have screws make the adjustment with the motor dead cold. Hit the throttle once to 'set' the choke. Loosen all three screws, and turn the housing until the choke plate begins to open a bit. Now tighten up the three screws and fire it up. Watch the choke plate as the motor warms up...it should begin to open almost right away. If not check that you have 12 volts going to the choke. If you have 12 volts and the choke plate is not moving at all the element inside may need to be replaced. It is a bi-metal spring and they do wear out.
    To replace the bi-metal spring remove the three screws again and remove the outer choke housing. The removal and replacement should be striaght forward.

    I hope this helps you somewhat. I highly recomend Doug Roe's book on Rochester carburetors...if you can't find it locally order it.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  15. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,173
    Likes Received:
    1,384
    Location:
    E-town baby!
    Well you can't make any real adjustments or further diagosis until the choke is back to working. There is a pressure switch near the distributor that the choke wire comes off of. It will not allow 12 volts to the choke unless it senses oil pressure (running motor). This prevents the choke from cycling when the key is turned to the on position without starting the truck.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  16. scavenger

    scavenger 1/2 ton status

    Joined:
    Mar 31, 2000
    Posts:
    111
    Likes Received:
    0
    Location:
    Southern Wisconsin
    Brian,
    Check the choke wire by having the ignition on but without the engine running. I would use a test light. After making sure you have a good ground to the test light, put the probe end into the end of the choke wire. If it lights up you have juice going to the choke, and the choke may have to be replaced. I am not sure if the choke wire is fused, but if the wire appears dead you may want to check your fuses before investing in a new choke. Do you know if you have the partially computer controlled Quadrajet. You can e-mail me at york01@charter.net if needed.
     
  17. scavenger

    scavenger 1/2 ton status

    Joined:
    Mar 31, 2000
    Posts:
    111
    Likes Received:
    0
    Location:
    Southern Wisconsin
    Brian,
    I believe tRustyK5 may be correct about not being able to get 12 volts to the choke until there is oil pressure. So I guess you will have to have it running to check that out.
     
  18. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    I am not sure If I have the one with te computer or not I did however check the fuse and it is good I put a new one in anyways.

    1985 GMC JIMMY
     
  19. steve85fla

    steve85fla Registered Member

    Joined:
    Mar 27, 2001
    Posts:
    83
    Likes Received:
    0
    Location:
    palm beach county FL
    '85......you have one that is computer controlled I believe. The best solution is to get a q-jet that is not computer controlled and slap it on there. I had similar problems and going to an older style carb fixed it, IMO the computer controlled carb is a real half-as*ed setup.
     
  20. JimmyJuneau

    JimmyJuneau 1/2 ton status

    Joined:
    Apr 11, 2001
    Posts:
    811
    Likes Received:
    0
    Location:
    Juneau, Alaska
    Well guys no luck in finding that damn indicator! Its missing in action so I guess Ill have to go to the gm dealer tommorow and get ripped off.

    1985 GMC JIMMY
     

Share This Page