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.

fuel system problem i think?

Discussion in 'The Garage' started by 79 blazer, Jul 9, 2005.

  1. 79 blazer

    79 blazer 1/2 ton status

    Joined:
    Dec 29, 2003
    Posts:
    114
    Likes Received:
    0
    Location:
    FORT COLLINS,CO
    going up a slighlty steep hill on the road on the way to some trails, i had to pull over and ride with a friend cause my engine started cutting out, when i would try to accelerate it would get worse the (less fuel i gave it the better it worked). so we just got back to the rig and i try to start it after a few long cranks and mashing the gas it fires up and runs weak unless i had the gas floored then when i try to put it in gear it dies, so after doing this a few times i get it in reverse and flip around on the road. now pointing downhill it runs perfect. on the way home slight hills that i had just driven on to get there, now make it start to cut out, especially when i try to accelerate. it would only keep going and cut out less if i gave it the smallest amount of gas i could? so what do i do?
    i think i need to adjust the carb but have no idea where to start with that. and also am considering the fuel pump?
    any help will be greatlt apreciated
     
  2. 79 blazer

    79 blazer 1/2 ton status

    Joined:
    Dec 29, 2003
    Posts:
    114
    Likes Received:
    0
    Location:
    FORT COLLINS,CO
    350 with edlebrock carb
     
  3. Mad-Dog

    Mad-Dog 1/2 ton status

    Joined:
    Mar 20, 2005
    Posts:
    548
    Likes Received:
    0
    Location:
    Ocklawaha,Fl
    check the float level inside the carb (requires disassembly)

    The pump should have 5-7 psi of fuel pressure, if it don't....replace it.
     
  4. 79 blazer

    79 blazer 1/2 ton status

    Joined:
    Dec 29, 2003
    Posts:
    114
    Likes Received:
    0
    Location:
    FORT COLLINS,CO
    what level should it be at? and how hard is this to do? a walk through would be great
     
  5. 79 blazer

    79 blazer 1/2 ton status

    Joined:
    Dec 29, 2003
    Posts:
    114
    Likes Received:
    0
    Location:
    FORT COLLINS,CO
  6. BIG*RED

    BIG*RED 1/2 ton status

    Joined:
    Mar 14, 2003
    Posts:
    1,094
    Likes Received:
    0
    also...
    when was the last time you replaced your fuel filter?..all of them?

    i have one just out side the tank..one in the engine compartment, and one inside the carb...
     
  7. BIG*RED

    BIG*RED 1/2 ton status

    Joined:
    Mar 14, 2003
    Posts:
    1,094
    Likes Received:
    0

    slight hijack here..

    my carbed engine is running between 10 to 11 psi..on a maunal fuel pump..is that bad?
     
  8. Mad-Dog

    Mad-Dog 1/2 ton status

    Joined:
    Mar 20, 2005
    Posts:
    548
    Likes Received:
    0
    Location:
    Ocklawaha,Fl
  9. 79 blazer

    79 blazer 1/2 ton status

    Joined:
    Dec 29, 2003
    Posts:
    114
    Likes Received:
    0
    Location:
    FORT COLLINS,CO
    so what would be a resonable price to get it pro tuned
     
  10. dirtwarrior17

    dirtwarrior17 Banned

    Joined:
    May 14, 2004
    Posts:
    1,820
    Likes Received:
    0
    Location:
    Redding, CA
    the answer is simple..... get a friend who knows a little about carbs or read up on it yourself( calll up edelbrock or find a website that shows you which needles do what and how much you should turn them).

    Most people never learn how to tune carbs because they are intimidated by it or just too lazy to mess with it but once you start playing with the high and lowspeed needles all it takes is common sense. Turn the needle clockwise and you lean it out, turn it counter clock wise and it gets richer. When its lean it will want to find the higher rpms at idle and vica versa for rich. the lowspeed usually controls the flow of fuel until it gets to about 1/4 or half throttle then the highspeed takes over. the highspeed needle won't affect idle, just past 1/4 or half throttle(depending on the carb).

    Find a local shop with a chassis dyno and pay 50 bucks for 1 hour of time on the dyno. All you have to do do a pull, tune it, do a pull tune it, until you get the AF right.

    If this is too much then i wouldn't pay more than 60 bucks. Generally they will all charge you by labor but I've never had one tuned.


    If its the fuel pump then you should see fuel coming out of a little hole in the pump.... that means the seal on the trampoline is broken and you need a new pump.

    If all else fails try the filter.
     
  11. Mad-Dog

    Mad-Dog 1/2 ton status

    Joined:
    Mar 20, 2005
    Posts:
    548
    Likes Received:
    0
    Location:
    Ocklawaha,Fl
    Yep..yep, carb tuning is a meticulous and time consuming task that i learned by research and hands on training...do a search or buy a book cuz it's too complicated to type it.
    I use a A/F ratio monitor, my ears, right foot and seat of the pants to calibrate the fuel system on my Scottsdale...it is very complicated and required removing and replacing the carb and float bowls several times before all the circuits were calibrated for the rich side of stoichiometry (14.7:1) or 14.7 parts air to 1 part fuel.....the rich side is around 12.5:1 and that's where i like to run at for maximum power.
    You don't need a expensive wide-band O2 sensor...just a basic unit with a heated 3-wire sensor.
    Start with the idle circuit then work your way thru the needles and main jets.
     
  12. dirtwarrior17

    dirtwarrior17 Banned

    Joined:
    May 14, 2004
    Posts:
    1,820
    Likes Received:
    0
    Location:
    Redding, CA
    *mild hijack*

    What is the range on a stock 88 efi 350 O2 sensor?
     
  13. Mad-Dog

    Mad-Dog 1/2 ton status

    Joined:
    Mar 20, 2005
    Posts:
    548
    Likes Received:
    0
    Location:
    Ocklawaha,Fl
    They are all about the same when it comes to range of measurement.....
    the king of queens is the wide-band unit which provides a higher level of accuracy in the area surrounding where stoichiometry is achieved.
     

Share This Page