Hesitation/Stall question

Small Block Mopar Engine

  1. Pumpkinduster

    Pumpkinduster Well-Known Member

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    Hey all after along time coming I have finally been taking the Duster for some test drives and enjoying it. But I have been running into some small issues it started with what I though and still could be a fuel issue.
    The motor is a 318 bored .30 over with a 0 deck height with the 302 heads, Comp Cam XE268H, Edelbrock Performer intake with an Edelbrock 1405 carb.
    Today I took it out on a good distance drive hit WOT a few times and driving it nice the rest of the time. When coming to a stop I pop it in neutral because it wants to drop the RPMs to low and try to stall. The Transmission is a 904 rebuilt by a local shop with a OEM stall converter. When I got home I was pulling in the driveway and wasn't touching the gas the car died. Fired right back up and pulled up the drive and did the same in the garage. After I parked it I looked at the fuel filter and it pretty much was empty. Is that to be expected?

    Typically I would assume the stall converter is the issue since it will try to die as soon as I drop it in reverse or drive and give it no gas. But I have had it stall out and not want to start again after stalling for about 10 minutes of trying to turn it over almost like it is starving for fuel.

    Has anyone experience anything like this running an OEM fuel pump with the setup above?
    I purchased the Edelbrock Performance pump that is self regulated at 5 or 6 psi, just haven't installed it yet. I am thinking that if my cam is suggesting that a 2000 stall works best this could be the issue, not high enough RPMS when in gear and idling to pump up enough fuel maybe?
    Just not sure if I am on the right path.

    image0.jpeg
     
    Last edited: Jan 16, 2021
  2. Dana67Dart

    Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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    Are those hoses fuel rated?

    The following only covers the empty fuel filter

    If your fuel filter is running empty you have one or more of a few problems.

    1. Float level
    2. Float sticking
    3. Fuel lines are getting hot enough to vaporize the fuel
    4. The fuel pump is malfunctioning
    5. There are restrictions in the fuel lines
    6. Any of the hoses connecting solid pipe to solid pipe are collapsing
    7. The sock filter on the fuel pickup is clogged
    8. The venting of the gas tank is clogged
    9. There is not enough fuel in the tank
    10. Pickup is bent
    11. The gas cap is non vented and it should be a venting type (I don't know if any A body cars ever used a vented cap)
    As for diagnosis...
    Start at one end and start checking.
     
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    • Murray

      Murray FABO Gold Member FABO Gold Member

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      An empty fuel filter should tell you something.
       
    • Bewy

      Bewy Well-Known Member

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      Seems odd that it 'fired right back up' if the f/filter was empty.....
      I have seen that when the FF is mounted horizontally, it can get an air lock in the upper half...but it is still passing fuel to the carb.

      This is a back to basics job.
      Remove the carb. Check the transfer slot position [ how much shows below t/blades at idle, should be 0.040" or less ]. Check float level, needle/seats & floats for sticking/binding. Unlike brand H & clones, you will not need any gaskets if you are careful. If you have compressed air, blow out all passages.

      Also, the RPM intake is a poor choice. You have a 6500 rpm intake & a 5500 rpm cam....
       
    • flyfish

      flyfish C8H18+N2O = :-D

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      That does not look like fuel line....I would put the garden hose back in the front yard and get some fuel line, then reevaluate (its probably vapor locking).​
       
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      • AJ/FormS

        AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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        Too much timing/ not enough Transferslot opening?

        Is that dishwasher hose? With the filter touching the hot head?
        As long as the hot fuel is under pressure, it tends to stay liquid. But as soon as you shut the pump off, if the valve at either end leaks the pressure down, the hot fuel tends to flash into vapor, and forces the fuel to flow out the leaking end. In the case of a horizontal filter, it will act like a vapor accumulator on whatever portion cannot get out of it. It is IMO, common to see those filters only half full of liquid.
        There are many different fuel molecules that make up gasoline. The most volatile ones can flash to vapor at around 90*F. The most stable ones are , IIRC around 395*F.
         
        Last edited: Jan 15, 2021
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        • RustyRatRod

          RustyRatRod I didn't do it. FABO Gold Member

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          You better do somethin about that upper hose fore long.
           
        • AJ/FormS

          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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          Mechanical Pump operation is dependent on exactly three things; rpm, head, and ability to pull. This assumes the return spring does it's job and keeps the pump arm on the eccentric.
          >If yur tank vent stops working, it gets harder and harder for the pump to pull fuel.
          > the fuel volume test in the FSM, stipulates a 500 rpm idle speed.
           
        • Pumpkinduster

          Pumpkinduster Well-Known Member

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          Thank you for the info, I was planning to pull the carb and check the float this weekend as well as the sock filter and lines.
          I don't believe the A body used a vented cap but I will look into that a little more as well. The car was a /6 runner before I swapped the motor so everything from the original setup with tank and lines even the carbon can or vapor can in the engine bay haven't been touched. I did just pull the line from the can last night when I was testing the pump with no spark to see if that made a difference but inconclusive at the time.
           
        • Pumpkinduster

          Pumpkinduster Well-Known Member

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          Thank you for the info.

          I disagree about the intake it is not a 6500 rpm it is an idle to 5500 rpm. This is straight from Edlebrocks specs.

          UPC 00085347021765
          Series Performer
          Gasket Or Seal Included No
          Vehicle Model Chrysler
          Availability Note Available to Order
          Warranty 12 Months
          Ec Basic Operating Rpm Range Idle-5500 RPM
           
        • Pumpkinduster

          Pumpkinduster Well-Known Member

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          Helix Racing Products 516-4737 Helix Racing Products High-Pressure Fuel Lines | Summit Racing
          Not a garden hose this is a fuel line. It is clear so I could see flow or any issues. But it is only temp. until I resolve the issue. I have the standard line that was removed to place back on it when done.
           
        • Pumpkinduster

          Pumpkinduster Well-Known Member

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          ??
           
        • Dana67Dart

          Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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          One of the things you can do is when it happens again, take the gas cap off, and restart. See if it does it again.

          If it doesn't happen again this will indicate a plugged vent system.

          My dart (273 v8), does a similar thing. When the engine is hot the fuel filter will be full of fuel, you can watch the filter drain, then the engine rpm starts to fall off then the filter starts to refill and the rpm increases. It will do this over and over.

          This, I believe, is due to fuel vaporizing in the fuel lines. During the above symptoms the fuel pressure stays in the 5-7 range till the rpm starts to drop off and then goes to about 3-4 as the filter refills and then back to 5-7.

          When I drive when it is super hot out and the engine is hotter than normal, the engine will die while accelerating
           
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          • AJ/FormS

            AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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            anecdotal;
            I run my alloy headed beast at a minimum coolant temp of 205*F, and
            I run no header wrap, and
            I run no insulation on my fuel lines, and
            I'm trying to remember what gasket I slid under the carb..... maybe the about 1/4 inch compressed paper one; IDK, and
            I run nothing but 87E10, and
            I run an ancient 750DP on an AirGap, and a 230*cam, with a 4-speed.
            My 367 has never on the hottest Manitoba summer's day had fuel troubles.To be fair, it rarely gets over 35*C here (which is like 95*F , if my math is right).
            The point is this; 87E10 boils easy. If any system could boil, it should be mine......

            Here's how I solved my problems; My secret weapons are;
            I mounted an aluminum oval air filter housing on the TOP of the hood, over an
            air-horn-sized hole in the hood, feeding fresh above-hood air down into the airhorn; with the top of the carb sealed to the hood, and,
            I have only a one-piece, hand-formed, 3/8" metal fuel line, from pump to carb. My filter is a large capacity metal EFI can, at the back, and
            I have a 68 Barracuda with those neat-O hood inserts. Well, I carved out some holes into the hood under them, and elevated the inserts as high as they would go on the factory studs, about 3/8", to vent the underhood heat when idling stationary, and/or, moving slowly, and
            I run 50% water, 50% antifreeze.
            IDK if my ideas are worth anything, but I have never, since the day I cut those holes in my hood, had fuel boiling issues. In fact, the carb is so stable that I can electronically retard the timing from the drivers seat to 5*, and idle around the fairgrounds, at 500/550 rpm, which is ~3.9 mph, all afternoon, on hard level flat ground, on the hottest days. If you try this; you will probably need a hi-flow waterpump and matching stat, and a 7 blade, all steel, hi-efficiency Mopar fan. Mine is on a Thermostatic clutch from an early 2000s Ford pick-up truck. Your results may vary, lol.
            anecdotalchit
             
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            • Bewy

              Bewy Well-Known Member

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              Your original post states Edelbrock RPM.
               
            • RustyRatRod

              RustyRatRod I didn't do it. FABO Gold Member

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              Look at the upper hose above the clamp. It's swollen.
               
            • RustyRatRod

              RustyRatRod I didn't do it. FABO Gold Member

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              Regardless of which intake you have, those numbers are simply a generic guide. Do you think the intake is gonna make the engine stop pulling at 5500? hardly.It all depends on the rest of your combination.
               
            • Pumpkinduster

              Pumpkinduster Well-Known Member

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              You are correct thank you for that catch. Has been corrected now.
               
            • Dana67Dart

              Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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            • Pumpkinduster

              Pumpkinduster Well-Known Member

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              Yeah that is starting to make more sense because I have only had it no want to start again after it has been heated for a bit. Granted his video he still had more fuel in the filter then I did.

              I did just check it and sure enough the filter is completely full now that all has settled and cold. So maybe I will try to find a way to shield or deflect the heat from the filter and see what the results are after that.
               
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