Stalls during idle

Discussion in 'GM Diesel & DuraMax' started by ColonialRovers, Jan 3, 2010.

  1. I have 94 GMC Suburban with 6.5 Turbo with 43,000 miles
    Drove it yesterday for about 200 miles no problems.

    I have a little over 1/2 tank of gas, filled it up at a Shop & Rob Exxon in Wilmington, NC.
    The fuel pumped slowly out of their tank into the GMC.

    Drove it off from there for about two miles and I stopped at a light, then the truck just shut off as I started to go from stop. Coasted for a few feet in neutral and restarted it, again started to drive it stalled again, shutting the engine off. Again I coasted and restarted to engine and it drove fine for another 100 miles, easily reaching speed of 78 mph.
    When I got closer to home I hit a few traffic lights it was ok, then when I got back into Greenville, it stalled once from at a light.

    Any thoughts, Would be helpful...

    Previous service included all fluids changed with in the last 120 days, new alternator, new batteries, new battery cables (except for one), all new filters (air, Oil & Fuel) and a fuel lift pump, something light that, by the local dealer. I am not familiar with diesels at all.
  2. tbplus10

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

    Any chance of water in the fuel?
  3. Maybe, I thought the fuel filter was suppose to prevent that. I did feel a little sputtering at 45 mph just after the first two times it shut down.

    This morning I purchased some Gunk additive and filled it up from my local station where I have been buying my diesel.

    It was hard starting this morning...
  4. tbplus10

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

    Depending on the amount of water in the system most of it will get filtered out.
    Winter months are hard on Diesels because of the condensation build-up in supply tanks and truck fuel tanks.
    At work during the winter months we have to drain the water separators about once a week on our Chevy Duramax's, if we dont they act a lot like the conditions your describing.
    You dont have a water separator in-line on the fuel supply?

    Water will gather in the tanks low spot, right where the fuel pump pick-up is usually.
  5. The truck is stock for the most part and I don't think it has a water separator in-line. If it did I would not know what it looks like.

    Do you know if the 94 Suburban has a draining port?
    Last edited: Jan 3, 2010
  6. tbplus10

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

    Not hands on familiar with the 94 model Diesels.
    I know some earlier models had separators, and some later models had separators but I couldnt say positively that yours does.
    I was trying to look through the maint. manual earlier but couldnt find the answer.
  7. Tim thanks for the info, I guess it was H2O in the system. I don't have a far commute with the truck, four blocks. I guess I'll knock this up to, buy from a name brand higher volume gas station and for the next few tanks run the fuel additive.
  8. turns out it was a lift pump controller that went bad, so GMC dealership says
  9. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    I was actually about to mention that.. I worked on the 6.5L alot.. Sounded just like it..

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