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  • nova2037
    Junior Member
    • Nov 2008
    • 6

    Suggestions

    I have been working on a 98 4.3 S10 for days and about to burn it. The problem is it acts like not getting enough fuel on take off. It will smother and belch in the intake. Worse when cold, but runs great wot and idle. I have replace plugs, wires, cap and rotor, fuel pump, filter and pressure regulator. I can't see anything on scanner, such as tps, coolant temp, or any other sensor problem. Hope this is enough info for a suggestion from someone. Thanks in advance.
  • MasterWrench
    Senior Member
    • Oct 2006
    • 1186

    #2
    Have you set the distributor using the scanner?

    Have you checked for an intake leak?
    MasterWrench

    Comment

    • nova2037
      Junior Member
      • Nov 2008
      • 6

      #3
      Yes I checked timing, it's -3 degrees. I replace upper intake gaskets when I replaced regulator.

      Comment

      • MasterWrench
        Senior Member
        • Oct 2006
        • 1186

        #4
        What are the oxygen sensors reading?
        MasterWrench

        Comment

        • GM guy
          Senior Member
          • Dec 2006
          • 122

          #5
          4.3l

          What is fuel pressure? Have you tried posting question on askateck.com ?

          Comment

          • nova2037
            Junior Member
            • Nov 2008
            • 6

            #6
            O2 sensor readings appear normal. Fuel pressure is 55 at idle and 60 when engine is brake torqued to 1500 to 2000 rpm where the smothering shows up. I thought askatech was a subscription service.

            Comment

            • GM guy
              Senior Member
              • Dec 2006
              • 122

              #7
              You get free askateck if your a current bundle purchaser or have shopkey or ondemand.

              Comment

              • GM guy
                Senior Member
                • Dec 2006
                • 122

                #8
                Originally posted by nova2037
                O2 sensor readings appear normal. Fuel pressure is 55 at idle and 60 when engine is brake torqued to 1500 to 2000 rpm where the smothering shows up.
                55 psi is cutting it close. poppets need 55-61 psi to open.

                Comment

                • Wheel
                  Senior Member
                  • Jul 2007
                  • 719

                  #9
                  Originally posted by nova2037
                  I have been working on a 98 4.3 S10 for days and about to burn it. The problem is it acts like not getting enough fuel on take off. It will smother and belch in the intake. Worse when cold, but runs great wot and idle. I have replace plugs, wires, cap and rotor, fuel pump, filter and pressure regulator. I can't see anything on scanner, such as tps, coolant temp, or any other sensor problem. Hope this is enough info for a suggestion from someone. Thanks in advance.
                  The first suggestion I would make would be to post some of that scan data, particularly in graph form if possible. We need to see long and short fuel trims, o2, load pids, maf and/or map, tps and/or throttle % for starters.
                  What may appear normal to you may really stand out to some of the veterans on this site. I like to look at data KOEO, idle, part throttle, cruise, full throttle, and under any circumstance the problem occurs, and compare these not only to each other, but to past experience.
                  This will help divide and conquer your problem, giving you a clue where to look.
                  You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

                  Comment

                  • Wheel
                    Senior Member
                    • Jul 2007
                    • 719

                    #10
                    Originally posted by nova2037
                    O2 sensor readings appear normal. Fuel pressure is 55 at idle and 60 when engine is brake torqued to 1500 to 2000 rpm where the smothering shows up. I thought askatech was a subscription service.
                    About the the o2 - please define normal for us in this case.

                    fuel pump:
                    55 psi is not enough. 54 psi is a no start on a cold day - usually.
                    Your pump may be new, but remember - new stands for Never Ever Worked. Much if not all of your problem I would say lies here with not enough pressure.
                    Find out why the low pressure. Is the pump getting enough voltage and amperage - how was the connector at the tank?( common issue ) compare voltage (+ and -) at the pump connector ( measure it loaded with something such as a headlight at least ) with battery voltage. If the difference is any more than about .3 to .5 volts, then I think you could have a problem.
                    You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

                    Comment

                    • nova2037
                      Junior Member
                      • Nov 2008
                      • 6

                      #11
                      I thank you all for the reply's. I believe the fuel pump is most likely problem as customer supplied it, of unknown origin. I will replace it with a good brand.

                      Comment

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