Car dies if I’m not giving it gas...

Electrical and Ignition

  1. 68_Valiant_Wilson

    68_Valiant_Wilson Active Member

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    So I was out a few nights ago and I was about to head home and got in the car and it started up fine. Turned on my lights since it was night. The lights were very dim but I didn’t worry to much. I was fixing to pull out of the parking lot and I pulled up to the stop sign and then it just sputtered out and died. I started it up again and made sure to give it a little bit more gas and I notice the lights lit up more then I took off making sure I gave it enough gas to not die. It drove fine all the way home. Turn signal would also slow way down if I was stopped and speed up if I pushed the gas. Once I got home, I stopped to put it into reverse and I could tell it came really close to dying but managed to park it before it died. I got out and haven’t drove it since. I thought alternator problems but it’s got a fairly new alternator. Could something be messing up my alternator? I posted a previous post a while back where I had hooked up the battery backwards but I was pretty sure I had fixed everything. Any comment/help is appreciated.
     
  2. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    If none of your wiring has been upgraded and none of the bypass fixes for the bulkhead connector have been done, then everything electrical slowing at idle is what can be expected and believe it or not pretty normal for an older Mopar.
    The MAD bypass for the charging system and bulkhead, plus a relay kit for your headlights will make a huge difference in those area's.
    There are also some alternator upgrades available like Denso versions, as well as regulator wiring upgrades that can be done.

    Part of the problem with these old girls is that all those higher amp loads run through many feet of what I see as undersized wires before the power ever gets to where it needs to go.
    Like I said, taking high draw loads like headlights and charging system off the factory wiring helps a ton.
    I use a lot of LED's replacements also, because they use a TON less electrical load.

    An example:
    When you turn on your headlights the power supply for them comes from the battery, down through the fusible link, across the amp meter, over to the headlight switch, back down through the dash harness to the hi/low beam switch and through another 10 feet of wire to the headlight.
    This is a HUGE draw before the power ever even gets to the bulb filament.
    All those connections, switches and everything have to carry all the load to light the bulb.
    With a headlight relay kit from our member Crackedback the switches and all that dash harness wire, switches terminals and such are relieved of that huge draw and related loss of amps along the way.
    After that one upgrade there is no big amp draw on the harness, connectors and switches any longer, as all that is now carried by the relays in the kit, and all your existing stuff has to do is activate the relay.
    This is a HUGE load off your existing wiring and switches, so they last WAY longer without that wear and tear.
    That leaves a bunch of amps left over for things like signals, wipers and blower motor.

    My car has a relay kit, a rewired charging system (MAD type bypass) and LED interior dash and gauges, brake/tail/turn lighting, so at a stop with the headlights, brakelights, a signal, wipers, heater and stereo going my lights don't dim at idle and the signals and heater don't slow, and I still have the original type alternator and charging system.
    One other easy one is to change to an electronic flasher unit, as they keep a steady flash speed because they don't rely on load to flash.


    This is just some examples of what cause and how to solve the problem you asked about.

    Dying when you let off the gas could be anything from idle speed adjustment to plugged up idle circuit in the carb.
    A simple one for the idle circuit is to screw the mixture screws in until they stop counting how many turns it takes.
    Remove them, shoot a shot od WD40 in each hole and hit each one with compressed air, put the screws all the way in and count the turns backing them out so they are about where they were.
    It takes about the same amount of time that it took to type it, and could very well solve your problem.
     
    Last edited: Nov 2, 2017
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    • Car15

      Car15 Active Member

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      Sounds more like a vacuum leak
       
    • TrailBeast

      TrailBeast AKA Mopars4us on Youtube

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      It may very well be, but we have to start by making sure everything else we can is right.
      For all we know the idle could just be set too low, and this is why he is noticing the dim lights more than usual.
      A vacuum leak can sometimes be found along the way while checking the other things, and my methods start with the simple things first and work my way up through the possibilities.
      Eliminating possibly simple idle circuit issues is first when the engines dies at lower RPM's.
      It is the way I do this type of diagnostics anyway.:D
       
      Last edited: Nov 5, 2017
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      • RustyRatRod

        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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        If you don't have a charging system tester, go to your local auto parts store and get your alternator tested.
         
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        • TrailBeast

          TrailBeast AKA Mopars4us on Youtube

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          Even just a basic simple volt meter connected to the battery will tell, if the person doesn't know what a loaded alternator sounds like.
          It is nice to have actual numbers though, and a basic volt/ohm meter is a nice tool to have.
           
        • Tooljunkie

          Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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          I really like having a voltmeter on my dash. Its like having a built in diagnostic tool.
           
        • BillGrissom

          BillGrissom Well-Known Member

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          Buy a cigarette lighter voltmeter to monitor as you drive, either a $15 digital one (Amazon) or the $6 Harbor Freight LED cheapie. You do have a dash ammeter, but since you don't mention it, a PO might have disabled it (common "fix"). Sounds more like a "high O/F" issue, either a vacuum leak (too much O) or plugged carburetor idle circuit (too little F). But, "low O/F" can also cause stalling, which is common from "carb float sinks" or "crud blocks inlet valve from seating" issues.

          A good start would be to tell us what engine and carburetor you have (why don't they?) and a few under-hood photos to know what condition we are talking about (modifications, frayed wires, rodent nests, ...). If you spray starter fluid into the air filter and that smooths the idle, you know it is an O/F problem.
           
        • toolmanmike

          toolmanmike Moderator Staff Member FABO Gold Member

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          Trailbeast said it. Hell, the thing could be idling at 300 rpm for all we know.
           
        • 68_Valiant_Wilson

          68_Valiant_Wilson Active Member

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          I think the problem was probably just the fact that the engine wasn’t retaining enough heat with the headers and it just hadn’t warmed up enough and was dying because it was too cold. I drove it again with my dad a few days later and it did fine. We also cleaned the carb and I think that probably helped too. Thanks for all the input. I really appreciate the help from all you guys who know what you’re doing so I can have a chance to fix it myself and learn something about these old mopars. I don’t get on here as often as I should.
           
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