Menu

93 F150 surging idle at times. Driving me nuts!

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here 93 F150 surging idle at times. Driving me nuts!

  • Creator
    Topic
  • #649698
    EricEric
    Participant

      I have spent many hours trying to diagnose this 93 f150 5.0. What happens is that it surges while it idles to the point it almost dies and then it can just started idling perfectly normal. It has 2 engine and 2 trans codes. Engine codes 173, 326. The truck has fresh tune up and a new IAC and I cleaned the EGR out checked it. I checked the TPS voltage and its right on. I have sprayed carb cleaner around everything. The odd thing is as soon as I unplug the vacuum line at the throttle body that goes to the charcoal canister purge solenoid it idles up and smooth and stops surging. I don’t understand why that vacuum port makes such a difference and others don’t. I tell myself the O2 is bad but i hold it at any rpm its fine. Help please

      Edit: Fuel pressure is 30-35 which is good

    Viewing 5 replies - 1 through 5 (of 5 total)
    • Author
      Replies
    • #649715
      college mancollege man
      Moderator
        #649764
        EricEric
        Participant

          I have had a fuel gauge on it. Why does it idle up and smooth when I pull that certain vacuum line off the throttle body. Is it disrupting vacuum to something I dont know of?

          #649860
          EricEric
          Participant

            Fuel filter is new and the regulator seems to be working correctly. Fuel pressure seems stable as it surges.

            #649866
            college mancollege man
            Moderator

              [quote=”Build#1″ post=122584]I have had a fuel gauge on it. Why does it idle up and smooth when I pull that certain vacuum line off the throttle body. Is it disrupting vacuum to something I dont know of?[/quote]

              If your pulling a vacuum line it will idle up do to the vacuum leak
              that was created. As for the smoothing out the computer is adding more
              fuel. When you tested fuel pressure and pulled the FP regulator did
              fuel pressure go up approx 10 psi? If you pull the vac line off the
              FPR and cap it does the engine run better?

              #649948
              EricEric
              Participant

                I will try this and get back to you. I did not plug the regulator off. I did unplug the vacuum line and had no change. I will put my gauge back on it in a day or so.

              Viewing 5 replies - 1 through 5 (of 5 total)
              • You must be logged in to reply to this topic.
              Loading…