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.

Blazer wont go over 35 MPH

Discussion in 'The Garage' started by tdcombs, May 10, 2005.

  1. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    Well i got my Blazer started but when i got the test drive it today it has no power and wont get over about 35 MPH. Its a 72 that has a 383 in it. At least thats what the previous owner told me. It has a Carter Carb on it. Does this carb have an internal fuel filter? I took the fuel line off at the carb and it was under pressure and shot fuel all over the engine bay.

    Any ideas? Where do i need to start? Im just wanting to get this thing running so i can drive it this summer. It was fun the 5 miles i got to drive it at slow speeds :) . Any help will be greatly appreciated.
     
  2. bigbadchev84

    bigbadchev84 1/2 ton status

    Joined:
    May 17, 2004
    Posts:
    2,191
    Likes Received:
    0
    Location:
    Hermiston, Oregon
    what kind of tranny? is it in 4 low?
     
  3. 1979jimmy350

    1979jimmy350 1/2 ton status

    Joined:
    Mar 24, 2004
    Posts:
    3,069
    Likes Received:
    0
    Location:
    Ann Arbor Mi
    if you have an auto check you vacume modulator line to make sure it is getting vacume
     
  4. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    Its an automatic tranny i think th350. I checked and its in 2wd that was the first thing i checked.

    Where is this vacume modulator line?
     
  5. 1979jimmy350

    1979jimmy350 1/2 ton status

    Joined:
    Mar 24, 2004
    Posts:
    3,069
    Likes Received:
    0
    Location:
    Ann Arbor Mi
    if you have a 350 tranny it is on the back side of the tranny it is a cylinder about an inch and a half across. It should have a rubber line running to a steel line that runs to the carb and attaches to a vacum port on the car.
     
  6. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    Any other ideas????

    Is the fuel line supposed to be under that much pressure when the truck isnt running?
     
  7. pvfjr

    pvfjr 1/2 ton status

    Joined:
    Feb 10, 2004
    Posts:
    2,425
    Likes Received:
    0
    Location:
    Oakridge, OR
    Hmm, sounds like when I bought my truck. Mine was a bad fuel pump, coupled with less than desireable spark plugs and distributor, and vapor lock issues.
     
  8. 89GMCSuburban

    89GMCSuburban 1/2 ton status

    Joined:
    Nov 15, 2001
    Posts:
    3,005
    Likes Received:
    0
    Location:
    Thornton, CO
    Mine did that, couldn't go over 30, trans shifted fine. Ended up having clogged fuel filter.

    I think Carter has one, but not sure where it is...
     
  9. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    It seems like a fuel filter but i replaced the inline one. Dont know where or if there is one in a carter. Looked where it would be on a Qjet and there was nothing there. Its a new tank with new fuel so i know its not bad fuel.

    Talked to a mechanic friend of mine that works for GM at lunch and he thought fuel pump so i guess ill pick one up after work and try that.
     
  10. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    is there more then one fuel filter inline? The one i replaced is a glass one thats just before the Carb. There isnt another one under the Blazer is there?
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    What does it do when you reach 35?

    Perhaps people that have had weak fuel pumps can comment, my only experience with a bad fuel pump was the engine stalled twice, and wouldn't start until the pump was replaced.

    When my engine was starved of fuel, (float bowl was emptying) once I hit the magic RPM, the vehicle started to buck violently as fuel was "injected" into the carb each cam revolution, but thats not enough quantity to supply an engine as large as it was under WOT. I could make it stop bucking by letting up on the gas.

    Could be something like an exhaust restriction as well as fuel. I can think of a few possibilities that could prevent acceleration beyond a certain point, I'd hate for you to replace a good part only to find it wasn't the problem. Unfortunately it's pretty hard to test the output of the pump unless you've got a fuel pressure gauge hooked up that you can watch.
     
  12. ramjet gmc

    ramjet gmc CK5 Staff Staff Member Moderator GMOTM Winner

    Joined:
    Dec 19, 2001
    Posts:
    3,370
    Likes Received:
    0
    Location:
    Milltown NJ 08850 NJ sucks
    """Could be something like an exhaust restriction"""

    that is what i was thinking but will it reve up quick and at what rpms is this happen?????
    --- i am going with the cloged cat thery--- as i fish for more info :D
     
  13. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri
    No cat and no tach. So thats not much help either. It doesnt buck just wont go any faster. Push the gas farther down and it doesnt make any difference. It doesnt seem to have alot of power getting up to 35 either.
     
  14. pvfjr

    pvfjr 1/2 ton status

    Joined:
    Feb 10, 2004
    Posts:
    2,425
    Likes Received:
    0
    Location:
    Oakridge, OR
    When my fuel pump went out it would still pump, just not enough. The truck would get into the 30's then would starve out, and start surging.
     
  15. wraenking

    wraenking 1/2 ton status

    Joined:
    Apr 30, 2003
    Posts:
    1,493
    Likes Received:
    0
    Location:
    Toms River, NJ
    have you checked your throttle cable for any play, or make sure its pulling all the way back?
     
  16. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri

    Just replaced the throttle cable and checked it so thats not the problem. It still pulls back more just nothing happens
     
  17. wraenking

    wraenking 1/2 ton status

    Joined:
    Apr 30, 2003
    Posts:
    1,493
    Likes Received:
    0
    Location:
    Toms River, NJ

    can you feel a difference at idle when you manually move the thorttle cable? or is it only under a load?
     
  18. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri

    By manually are you meaning work the linkage by hand under the hood?
     
  19. wraenking

    wraenking 1/2 ton status

    Joined:
    Apr 30, 2003
    Posts:
    1,493
    Likes Received:
    0
    Location:
    Toms River, NJ

    yes
     
  20. tdcombs

    tdcombs Registered Member

    Joined:
    Apr 12, 2005
    Posts:
    98
    Likes Received:
    0
    Location:
    missouri

    Havent tried that. Just guessing that itll do the same as with the foot pedel though because its not binding up at all.
     

Share This Page