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.

I hate whe the truck is running good

Discussion in 'The Garage' started by fright89, May 15, 2002.

  1. fright89

    fright89 1/2 ton status

    Joined:
    Sep 27, 2001
    Posts:
    279
    Likes Received:
    0
    Location:
    boston
    Just had the truck tuned up and it was running great. When my truck runs that good it scares me bad. You just get this feeling this is to good, something's gutta goes wrong, and usually does. My car needs brakes and i have been doing field service calls in the truck. Im usually on site fixing computers but one of my field buddies is out and I'm filling in. well shore enough about 30 miles from nowhere the truck farts bad and stalls out. WTF. Got it started again and managed to get it home but it did stall out about ten more times on the way home. I was out on the big road when it deiced to get really bad and I had to pull into the break down lane many times. That may sound all well and good but out here in Massachusetts they are active in places during rush hour. That meens when your stopped up against the guard rail all those commuters are coming right at you as fast as the can with no place to bail out when the finely notice all the cars stooped in there lane.

    It appears the truck is not getting a constant flow of fuel. It's a 350 TBI.


    I did watch the jets while the truck was running. Then I would see fuel stop coming from the jets and the truck would stall. It was hard to tell if the fuel stopped coming out because the truck was stalling or the other way around. Kind of a pavement ponder, I like driving not fixing and I don't know to much about TBI

    How much fuel should I see coming out of the jets when I throttle it when the truck is not running?
    Has any one had problems with Mallory fuel pumps? I took the stocker out of the tank and put a 4060fi on the frame it's only about a year old.

    Yes I will change the fuel filter and I did check the ground for the fuel pump.
    There are actually a couple questions in this post and any suggestions would be appreciated.

    Thanks
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,170
    Likes Received:
    1,379
    Location:
    E-town baby!
    Maybe not enough fuel pressure? The spray pattern under the injector tips should be a fine conical mist when running. Any dripping is not good. Proper fuel pressure for a TBI should be 12 psi or so.

    Rene
     
  3. TopOff

    TopOff 1/2 ton status

    Joined:
    Jan 16, 2002
    Posts:
    1,760
    Likes Received:
    0
    Location:
    Folsom, ca
    If the computer does not see ignition triggering, the injectors do not fire.

    Did you replace the HEI module during the tune-up?
     
  4. GMMANIAC

    GMMANIAC Registered Member

    Joined:
    May 1, 2002
    Posts:
    53
    Likes Received:
    0
    Location:
    San Antonio, Tx.
    Sounds as if your fuel pump may be giving you fits. I doubt the relay could do it because the there is a backup system incorporated it the oil pressure switch. One other thing to check if you losing fuel is the coolant sensor at the front of your intake, I have seen the plug ends corrode and have had seen sensors fail.
     
  5. Calclips

    Calclips 1/2 ton status

    Joined:
    Apr 4, 2001
    Posts:
    1,005
    Likes Received:
    0
    Location:
    Swartz Creek, Michigan/Flint while in school
    My 90 GMC 1/2 ton did this same thing. It was the ignition module, just as TopOff stated. I chased this problem all arround the truck until I finally found out that it was the module. Without the module, the injectors do not fire at all and the motor gets no fuel or spark... For a stupid piece of plastic with some electrical crap inside, its kinda expensive. CarQuest had two different ones, a 30 dollar one and a 70 dollar one... DON'T get the cheap one I was told that it would "leave me stranded" in about 3 months.
     
  6. fright89

    fright89 1/2 ton status

    Joined:
    Sep 27, 2001
    Posts:
    279
    Likes Received:
    0
    Location:
    boston
    thanks. I will try the hei modeul tonight and let you know
     
  7. Calclips

    Calclips 1/2 ton status

    Joined:
    Apr 4, 2001
    Posts:
    1,005
    Likes Received:
    0
    Location:
    Swartz Creek, Michigan/Flint while in school
    I don't know if they'd be the same part, but I can get you the part number off of my module. I think that they're the same, it looks like you have an 89-91 from your pics. Does anyone know if his module would be the same as my 90 1/2 ton pickup.... they're both 5.7L TBI.
     
  8. fright89

    fright89 1/2 ton status

    Joined:
    Sep 27, 2001
    Posts:
    279
    Likes Received:
    0
    Location:
    boston
    got the modeul and put it in but that did not help. changed my fuel filter but it still dies after about 3 or 4 minites. thanks for the help. maby I will repost over in 2nd gen.
     

Share This Page