Cold Weather starting

Engine, Transmission & Driveline

  1. Newportnuts

    Newportnuts New Member

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    my carb has been serviced and the car will fire up...I let it warm up until the cold light comes on I put her in drive and head down the road..if I turn the car right or left she will stall or even going straight she will hesitate and stall. She will start back up and then run fine and no more problems..Am i not letting her warm up enough? How long? she does not like cold weather...have a 400 b block 2 barrel carb.
     
  2. Mr C

    Mr C Senior Member

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    Is it on high idle when you drive off? sounds like choke is sticking on one of the steps and after it stalls and you "reset" it (do you pump the gas?) it winds up fully open and then you're fine.
     
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  3. Newportnuts

    Newportnuts New Member

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    thanks for your reply Mr C...after the initial start up, I will pump the gas to eliminate the high idle..im ok as i initially move the car..when it stalls i just start up under normal conditions...should I pump the gas again? i worry about flooding the carb
     
  4. Newport 66

    Newport 66 Old Man with a Hat FCBO Gold Member

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    Check the choke adjustment and the vacuum operated choke pull-off position when completely cold. Also how many RPMs is your idle at once warmed up? Power steering will pull down the engine speed enough on a cold morning to effect driveability until warmed up.
     
  5. CBODY67

    CBODY67 Senior Member

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    I'm suspecting that everything is set to factory specs, as a baseline?

    From my experiences with cold start performance (whether in the more milder temps we see in the winter in N TX or the times when it's much colder, the main thing is to get a quick start initially. This means a reasonably short crank time, which is possible.

    Once the engine starts, let it get to where it will run reliably and not stall by itself. Probably a minute or so to get the oil well-circulating in the passages and for any valve lifter "ticks" to go away. Then gently punch the throttle so the engine will come off of the top of the fast idle cam, for smoother engagement of the automatic transmission (which probably should be in "N" when the engine starts (to ensure the torque converter fills quickly).

    Is that first trans-in-gear moment where it stalls or at the first stop sign a block or so away?

    Here's how I like for my cars to be set-up and act. On the first cold start, it needs to run quickly and easily. Which means the choke is not too rich, after the initial pre-start "punch" to allow the choke mechanism to do its thing. BUT when the engine is fully warmed-up after 10 minutes of drive-time, then shut if off and see how the choke is set.

    Ensure that you can easily move the choke valve to the closed position, which might need for the throttle to be opened a slight bit so the fast idle cam can reach its appropriate "full on" position, with the choke valve held fully closed. Then manually move the vacuum choke pull-off to its fully-operational (as when the engine is running and it's getting full manifold vacuum), to see where the resultant choke valve position ends up. There is a factory spec for that dimension. ALSO ensure that the choke valve moves freely and does not contact any of the carb castings near it.

    As fof the fast idle idle speeds, I usually set the screw so that the fast idle cam can attain its first step with a little bit of extra idle speed from where the base idle speed might be (seems like the base idle speed is 700rpm on that set-up?). It'll still have enough "fast idle cam" to provide the needed fast idle speeds initially, but as things warm up, the transition to "full hot" will be a bit apparent.

    Then, I'll tweak the choke thermostat setting to ensure that it is fully closed (after moving the throttle open from base idle at ambient 65 degrees or so. That means ENGINE metal temp, as with intake manifold metal temp, is "ambient" with the outside temp. This closing at that ambient temp is "just enough tension to close it", not a "snap shut" situation by any means, but "just closed". Then double-check how much the choke pull-off will move it further opens as te engine starts (which can be done manually, as mentioned above).

    With an older choke thermostatic coil, the coil can gain tension with age, so using the factory setting for a new one can be a notch or so too rich. On your engine, everything should be calibrated toward the lean side of things already. But age can still be a factor.

    To further refine how things work, from this point, you'll need to pay attention to how everything works, sounds, and acts. Upon initial start-up, about 30 seconds after that initial fire-up, and then when you put it in gear a minute or so later.

    During your cold testing, with the trans in gear, you can do a gentle application (with the foot brake full ON!) to see how the engine will react to throttle inputs. Immediately and after a minute or so run time.

    Be sure to ensure the ignition system is in good condition (which it should be if it's the OEM Chrysler electronic system, by observation). Then ensure the plug wires are decent, too. Lastly, the important part of that "chain" is the spark plugs, gap and gap style. "Gap style"? Yes.

    The normal spark plugs we're used to seeing have a center ground electrode that completely covers the electrode in the ceramic. This is "normal", but has been found to hamper flame kernel expansion into the fuel/air mixture. Most of the "performance/efficiency" spark plugs of the '90s used a "cut-back" ground electrode to decrease this affect. What Champion used to term "J-gap" on some of their racing spark plugs of the '60s. End result, more of the flame kernel is exposed to the mixture for a better "fire". I did that on the Champions that we had in the '66 Newport, back in the 'later '60s after I read about the J-Gap deal. I spent some nice afternoons with a point file modifying those plus in the Chrysler, getting the plug gap just right, too.

    In later times, the NGK V-Power plus does the same thing. The similar Accel U-Groove plugs don't seem to quite work as well as the NGK V-Powers do, by observation. There is a particular NGK OEM Toyota plug that pre-ceded the release of the V-Power plugs. When I put them in my '80 Newport, replacing some nice-operating Autolites (which came in the car when I bought it used), I could tell an immediate difference. The Toyota pamphlet I got on the plugs talked about how they will burn a leaner mixture than a normal plug. Had a chart of that, related to spark plug gaps.

    End result, they seem to work better on an "open chamber" (Chrysler LA) than on a full wedge chamger (B/RB) in their cold start performance, but they are better than a normal spark plug, either way.

    End result, on my '77 Camaro in this case (4160 Holley, emissions spec for a '79 Corvette L82), it fires off quickly on the coldest mornings. After the rpm stabilizes, it goes into "R" and I back out of the driveway. If it might start to falter, a quick and short (just barely a quick tap of the pedal) and it immediately comes back. Then I back out into the street, stop, put it in "D", and drive to the end of the block, turn, and proceed on to the first stop sign at the end of that block. No more falters or anything. Then a few blocks later, at the next stop sign, it's on the bottom of the fast idle cam and everything works normally from there. Even with an open element air cleaner.

    Now, you can somewhat replicate the V-Power Cut-back electrode by using a pair of pliers and gently turning the ground electrode a bit to uncover the center electrode about 1/2 way, still maintaining a .035"-.040" plug gap. The newer NGK Iridiums, with their thin-wire electrodes are supposed to work as well, too.

    So, past the basic factory specs, to get to where it works well can take some "try and see" small changes to the factory settings. Over time. But when you get it done, it'll be a good investment in time and experience. Having the FSM for that carb can be good to see what and how things work on the 2210-family Holley 2bbl, too.

    Then, when the weather gets warmer, double-check the operation to see if things still work well for the warmer weather, for general principles. IF the factory heat riser valve might be stuck 1/2 open (as ours typically were), then it might take a bit finer tune for good cold performance, but as I did these things with an open element (unheated) air cleaner with an aluminum intake and an open heat riser valve (on the Camaro), your car with an iron intake might need a bit more run time initially, but probably not much more. Just have to play it and see. Learning how it all works best and then not trying to make it do something it doesn't want to until it gets warmed up.

    Key thing is to get the choke "off" as soon as possible without any stalls or weak sports in driveability from the initial cold start.

    Enjoy!
    CBODY67
     
  6. Gerald Morris

    Gerald Morris Well-Known Member

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    One CAN always just rig a manual choke cable, as I have. Its simple, permits you to set your choke where you want it after lubricating the cable well and breaking it in a little, and also permits you to use that fast idle at times when you may want it withOUT choking your carburetor fully. Manual chokes are a requirement for any Morrismobiles I drive. I might yet rig a manual spark advance using a choke cable or such also, as that too has advantages.....
     
  7. stubs300

    stubs300 Senior Member

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    This is your problem right here! You kick the choke off before the vehicle is happy and warm and thus you have this problem. Why don't you just let the choke do it's job and naturally shut itself off and help eliminate the problem? I guess maybe that's asking for to much from you?
     
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  8. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    All old Mopars are cold blooded. So,let her warm up some more before kicking off the high idle.
    If it helps,install an aftermarket temp gauge for a better idea where she is rather than rely on the cold light. Or use a laser temp gun and point it to the thermosat housing.
    Regarding the "COLD" light, do not kick off the high idle until the light goes out.
    Then drive on.
    Hope this helps
     
  9. stubs300

    stubs300 Senior Member

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    And even then you can have problems.