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hard starts and stalls

Discussion in 'GM Powertrain' started by leother, Aug 18, 2007.

  1. leother

    leother New Member

    i have a 1996 GMC Suburban SLT 2500
    Diesel

    Symptoms:
    >Starts right away in the morning but dies after a few seconds
    >abruptly starts right after but sometimes not
    >intermittently stalls even i have my foot on the accelerator
    >recently it doesn't start at all
    >it cranks the engine but doesn't follow through

    >a few weeks ago, it is running really well, but one morning it stalls after a few miles from home, good thing it started right away
    >thinking it maybe a cold engine, i proceeded with my destination

    the next morning, i warmed the engine for 5 minutes and so, and had my trip going thru well

    just 3 days ago, i forgot to warmed it up and go right away, i sufferred 5 start-go-die situations in a main thoroughfare, caused a lot of havoc and chaos(LOL)

    yesterday, i had it out of the garage, started right away and die twice, once out of the garage, it dies again, and never started again

    This morning , we found out that we had a loose connection on the auxillary battery, it started but dies twice

    i banged the fuel tank as advice by other forums so as to reset the fuel pump and i think i does the trick.

    it runs quite fine now but am not sure to what really the problem is. please enlighten me folks!

    by the way i am from the philippines kinda low on budget and importing is a tedious process!
    Last edited: Aug 18, 2007
  2. Dj Friction

    Dj Friction Rockstar 100 Posts

    Welcome to GM Truck Club......

    Now with your problem. Have you had the fuel filters changed lately??

    2 real common things could be going on. 1-Water is the Diesel. ( by banging on the fuel tank you could have stirred the water up and do not have as big of concentration, but if that is the case it will return.
    2-Water in the fuel filter (or water separation filter -if you have one)

    I would check those simple things first than you can check some other more complicated things.

    Good Luck
  3. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Check the fuel filters

    Yes, the fuel filter(s) are suspect. My buddy has an 06 diesel and it ran poorly and the check engine light came on while towing a boat up a grade. The truck made the grade but very slowly. Took it to the dealer the next day (extended warranty) and they changed all the fuel filters. Problem gone.
  4. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    After having experienced the same issues a few times with Diesel trucks I agree that it may be water in the fuel.
    You can try a water dryer additive in the fuel but best results will come by changing the fuel filters, drain the tank of all the fuel to ensure it has no more water, and check the fuel line between the injector rail and where it attaches to the frame (coming from the fuel tank) almost all GM export Diesels have a water separator mounted inline in this area. It may be full and need emptying.
    A trick I learned to filter fuel going into the fuel tank was to carry a supply of cotton socks (must be cotton no synthetic blends), place the sock over the nozzle, place the nozzle in the tank and pump the fuel. Cotton will soak up the water and allow fuel to flow through, this also filters the fuel for any scale or rust that may come out of the pump. I learned this trick while stationed at Cebu Pt. Our underground storage tanks were from WWII and even after being cleaned and purged always had lots water and scale from the humidity in the PI.
  5. leother

    leother New Member

    details pls

    Thanks for your replies
    Your help would greatly be appreciated if you'll guide me with a step by step procedure in doin such tasks. i know i'm not a mechanic, but i was hoping that your quick and practical tips would be of great ease. with your guidance, i am assured that i'm doing the right thing, tnx again



    Could you please reiterate the cotton sock thing? will i drain the tank and have this sock fixed for every filling? do i get that right? tnx
  6. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Yes, every time you put fuel in the trucks fuel tank place a cotton sock over the end of the fillng stations fuel nozzle to stop water and debris from going into the trucks fuel tank along with the fuel.

    Draining the trucks fuel tank is an option to fix this problem, I suspect over the years you have gotten a build-up of water and scale in the trucks fuel tank.
  7. leother

    leother New Member

    location map

    where can i found the water separator?
    is the water separator and the fuel filter the same?
  8. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    If it was equipped the water seperarator should be inline on the fuel supply line.
  9. leother

    leother New Member

    conclusion but not the ending

    i had a mechanic come over and he just bleed the fuel line and koala it's all well. it cranked good right away, it's a small faucet like knob just above and between the engine and the radiator. he let's the diesel drip a bit and it surely does the trick
    but........
    a new problem i think arise.... one morning my dad started it up but for several seconds it dies again and never did it started until early afternoon...
    the hard part of it is we have to jumpstart the battery because it drains because of intermittent cranking...
    Question?
    what is the function of the auxillary battery?Could it have an effect to the fuel system if its drained or loose?
    I seldom use this van because of its condition, problem is after two days of not starting it, we have to jumpstart it...
  10. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    The aux battery can affect starting if it has a bad cell, this battery completes the starting system circuit. While the engines running the aux battery has no affect on the electrical or fuel system, it could be thought of as a spare electrical storage cell.

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