Percolation? Heat soak? Don't drive during summer??

Fuel and Air Systems

  1. DentalDart

    DentalDart Well-Known Member

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    I havent tried with a wire and plug, but I can try it out.
     
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    • 318willrun

      318willrun Utube channel 318willrun

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      well, my thought is, if you have spark coming out of the distributor when it's HOT and Failing to Start, then you know it's fuel related.
       
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      • 512Stroker

        512Stroker We are all here because we are not all there.

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        I should be close to 6psi when hot.
        Its easy and cheap to do.
        Without knowing the fuel pressure at the carb you are just wasting time and $
         
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        • j par

          j par Well-hung Member

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          We already discussed a option for checking to see if it's getting fuel. But he did say he was getting smoke which is really fuel vapor when he pumps the carb when it's hot. And when it cools down he can see the accelerator pump squirting.
          And in some of this you may not have read but I did recommend a little squirt bottle of gas the next time it does this to put a little touch in the carburetor and see if it fires... This is what's leading the discussion to electrical... Fuel is way easy to verify... Without buying pressure gauges and all that...
           
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          • j par

            j par Well-hung Member

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            Very simple if car dies and you splash gas in carb and it fires it's a fuel delivery if it does not fire you just gave it fuel so that's not the problem it's electrical..
            A simple as it gets...
             
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            • dartfreak75

              dartfreak75 Restore it, Dont part it! FABO Gold Member

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              I havent read all 5 pages yet so you may have found your answer. But from your op i think your problem is vapor lock. Get that tank vented. Just buy a fuel filter with the third outlet. Then run a line from there to the tank. Non ethanol gas may help also. Our local circle k has it.
               
            • 69_340_GTS

              69_340_GTS Well-Known Member

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              But, DD's symptoms are the same as what my car had. And I had already totally eliminated any chance it could be fuel-related. And the car has run great, never skipped a beat, for at least 5 summers now.
               
            • 512Stroker

              512Stroker We are all here because we are not all there.

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              You dont need to buy a fuel pressure gauge most auto parts store will loan you one. Fuel pressure is the basis for any type of fuel system trouble shooting, sure there are all kinds of wife's tale's and home cooked options to follow and perform. I prefer to take a more stepped scientific approach by using real fancy tools like gauges and meters LOL
              Disagree all you what I still want to know want the fuel pressure and possible the fuel flow rate when the OP's shit is hot.
               
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              • Phreakish

                Phreakish Well-Known Member

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                Covered. Not likely the issue (still has fuel vapor from the accel pump after the engine quits). Non-ethanol in Vegas is not widely available.
                 
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                • AJ/FormS

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

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                  Fuel pressure at idle means nothing, unless it is high enough to blow the needles off the seats.
                  Actually, fuel pressure for a streeter means pretty much nothing , period, unless it blows by the needles.
                  The only time fuel pressure means anything, is at the big end of the track, and even then; it only has to be enough to keep up with what the engine is consuming.
                  The thing that means anything at all, is volume. So if the pump, can't keep up at idle, then the very first test I'd be doing is a volume test.
                  But in this case, the car has already been running and driving for a third of an hour, so until this moment or shortly before, both the pressure and the volume were fine. As to a loss of fuel delivery then, IMO, the only considerations are; tank venting, and maybe, pump efficiency.
                  What I have found is that when the tank comes under vacuum the pump stalls because the diaphragm fails to return, and so the pump-arm just flops around uselessly.
                  But OP has already stated that the tank vent is "fine".
                  So by process of elimination, we have sorta come to electrical....
                  unless the valves are failing to close.

                  BTW, OP
                  the ignition system will run just fine without the coil ballast. In a pinch, I have run the ECU of either side of the dual-ballast and just jumpered power to the coil. My Big Yellow Sq-top Accell Super Coil has spent a few hours running full voltage and survived just fine. In fact, it has spent a good bit of time jumpered straight to the battery, bypassing the entire electrical system. I carry a jumper in my kit, just for such an occasion. You won't see my car on the side of the road on a Sunday, with me walking, unless there is also a huge puddle of liquid under it.
                  I don't carry a cellphone and never will. To me, a cellphone is such a flippin' distraction,and a crutch for all kinds of bad manners. If I am with a person who interrupts our conversation, to answers his/her phone,
                  chances are I'm on the way of capital G, G-o-n-e.
                  And that goes for the parts guy at the parts counter too. I'm here with cash in hand to buy something. If he answers his phone while serving me, guess what: I'm gone; He ain't the only game in town.
                  But I digress..... lol
                   
                  Last edited: Sep 21, 2020
                • RammerJammer75

                  RammerJammer75 Well-Known Member

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                  The more that I think about it, the more I believe it is electrical too. At first it did seem like fuel issue, but he says if it sits and runs or drives for the allotted time it dies regardless. That sounds like something in the electronics is getting hot and breaking down, that and the weird spark when the key is turned on.
                   
                • Dana67Dart

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

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                  SUMMERY....

                  here is what we know right now.

                  1. Car was working fine with all the same components
                  2. DD removed things and painted the engine and engine compartment.
                  3. After putting everything back engine will die after a few minutes in the LV heat.
                  4. After car dies, fuel can be seen in the plenum
                  5. When key is turned to on / start the coil will fire as if distributer was spinning ( old issue never solved)

                  What is not conclusively known

                  1. Does the engine have spark to the plugs after it dies.
                  2. Does the spark fire when it is supposed to after it dies.
                  3. Does the carb have fuel in the bowls after it dies
                  What needs to be determined

                  1. If fuel or starter fluid is put into the carb after it dies does it fire up
                  2. If the ECU is changed after it dies does it fire up.
                  3. Is there power to the coil and ECU after it dies

                  Before we all diagnose the problem we should understand what the problem is.

                  Too many variables at this point.
                   
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                  • kursplat

                    kursplat FABO Gold Member FABO Gold Member

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                    unless it's already flooded
                     
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                    • Dana67Dart

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

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                      Full throttle and cranking will clear a flooded engine, should not take 30 minutes to clear
                       
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                      • kursplat

                        kursplat FABO Gold Member FABO Gold Member

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                        i agree, but i didn't re-read the whole thread to see if he knows or has done that
                         
                      • Dana67Dart

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

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                        I don't think it was brought up.
                         
                      • DentalDart

                        DentalDart Well-Known Member

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                        Last time it died when I drove it to the gas station, the car wouldn't start for about 4hrs.... i left the car and went back after waiting 2 hrs and it still wouldn't start. So left it and went back another 2hrs, at that time it started.
                         
                      • AJ/FormS

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

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                        Maybe;
                        the ring gaps are closing up, and the engine is getting tight enough to stall. Oh wait, it cranks right after stalling.
                        Or maybe;
                        the valve lash is closing up, and the effective Compression ratio is dropping to less than what is required to stay running.
                        Or maybe;
                        a rod bearing has spun, and finally locked up.
                        Yes, I'm kidding.

                        But what gets me is, OP doesn't mention bad engine behavior prior to stalling. We all know that running out of gas at speed, breeds bad engine behavior. It stutters, missfires, slows down, gets mushy, and finally, even pops thru the carb if you try to accelerate back to speed. I didn't read that anywhere.
                        OPs car seems to just coast to a stop without drama.
                        I had a Magnetic pic-up do that. Actually, a couple of them.
                        The output on those is really really tiny, and it takes an amplifier just to bring it up to a level that the coil can work with. And the reluctor gap has to be small enough to produce a well-defined trigger that the amp can sense is a real signal. By experimentation I have found the amp to work with the gap set anywhere in the range of Zero to .030; but IIRC the spec is .008 to .011.
                         
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                        • 69_340_GTS

                          69_340_GTS Well-Known Member

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                          Yep, because the electrical stuff cooled down, and started working again. IMHO, of course.
                           
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                          • 512Stroker

                            512Stroker We are all here because we are not all there.

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                            AJ as far as the fuel issue I think we are on the same page just attacking it from 2 different angles - same result.
                            Plane and simple if there is no fuel in the carb it is no going to run.
                            I to do not measure fuel pressure at idle.
                            Hell it could be both fuel and ignition, stranger things have happened.
                             
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                            • Krooser

                              Krooser Reform School Graduate

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                              Am I the only one who thinks 36 degrees of timing is too much?
                               
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                              • DentalDart

                                DentalDart Well-Known Member

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                                36* all in timing, and a limiting kit was installed in the distributor. My initial is like 15, I can't remember off the top of my head. Its in my build thread. The engine was put back together correctly, cam was correctly installed, timing was done correctly, carb adjusted correctly, etc. Not because of me, but a very smart and generous person from FABO offered to help me with it and he made sure it was done correctly. :)
                                 
                              • DentalDart

                                DentalDart Well-Known Member

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                                The only bad behavior it does is it starts to stutter like its losing fuel, but giving it gas doesn't change anything. I swear it sounds as if its running out of gas, but none of the lines are hot and the carb is cool as a whistle when it does it... no misfires, no backfire, no nothing, only stuttering. Ill see if I can't get a video of it today, I'm just finishing up with my patient charts for the day.
                                 
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                                • j par

                                  j par Well-hung Member

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                                  so you thinking after it runs for 15 minutes with a big rush of gas just floods in there and kills the car? That would be a first for me... but then after restarts drives fine for another little while till it gets too hot then a big rush of gas comes in and floods it...:realcrazy:...
                                   
                                • yellow rose

                                  yellow rose Master Of Insanity

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                                  It IS running out of fuel. Why it takes 4 hours to restart I can’t say, but when it boils the fuel out the carb is empty. It takes a bit to get the bowls filled up.

                                  Do a google search on those carbs. It’s not a secret. You keep saying it’s cool, but that’s just WRONG. It can’t be. It may not be 400 degrees, but it’s hot enough to boil the fuel off.

                                  I’ve had it happen at stop lights, waiting for damn train and once, the last straw with this one was a long line of traffic last year for road construction and it quit twice on me.

                                  It’s boiling the fuel out of it.
                                   
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