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idling problems and cold mornings

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tecton, Jan 20, 2004.

  1. tecton

    tecton 1/2 ton status

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    last night, i start my truck after about a day of sitting at around 17 degrees. No biggy...started right up. I left it running, and came back in, and took a shower. Probably 15 minutes later i come back outside and its jumped to around 2000rpm. That happens all the time. So i kick it down and it drops to 4-500rpm!!! Truck feels like someone is outside pushing it left to right. I figure its just cold, so i rev the engine a few times up to 3k and its still doing it. I ignore and and take off down the road. Imediately i notice a huge loss of power. Its like i stomp the gas and its just got nothing more to give. Usually this will happen, and i will hear something snap lose (something in the carb frozen?) and then it will be fine. But it didnt happen. All evening i was only able to go about 45mph unless i stood on the pedal. Huge loss of power. And the way it would idle it felt like it was about to die. Literally shaking the truck.

    Anything i should look for or get fixed? /forums/images/graemlins/confused.gif
     
  2. Goober

    Goober 1/2 ton status

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    It sounds like the carb is icing up. That can happen even if it's above freezing outside. The effect can be compared to the windchill factor. If it is 20 degrees outside and you have a strong wind then the windchill factor will make it feel MUCH colder. When your carb is nice and cold then it is sometimes possible for ice to form right where the air velocity is greatest, inside your venturi's. That makes fuel delivery much more difficult.

    Here are a few ideas:

    <ul type="square"> [*]When it's cold outside, keep your gas tank full to prevent condensation and add a can of gas line treatment every once in awhile. The ONLY good thing about that stuff is the fact that it is really just alcohol so it will absorb any water that finds it's way into your tank.

    [*]Have you still got the stock heat riser tube in place? The warm air intake is designed specifically for cold engine operation. There is a temperature activated vacuum switch that will close off when the engine warms up, disabling the warm air intake. You could possibly fabricate one and it would really help out on those cold starts.

    [*]Have you got the crossover water jacket in the intake manifold blocked off? Some guys insist that these get blocked to "improve performance" but for a daily driver in colder climates you really need that heat to run smooth. Most gasket sets will have the metal restrictor plates with a round hole in the center. Put one in each side and you should be good to go.

    [*]Adjust your high idle down a bit (lowers wind velocity in the venturi) or wait a minute or two after you start it to kick it down to the intermediate idle cam.

    [*]Get a circulating block heater. If you are letting the truck run to get it warmed up inside the you should really consider a block heater. The best ones out there are plumbed into your heater core lines. They warm and circulate coolant so your engine is fairly warm right when you start it. Compared to the cost of gas that your burn up by letting your truck idle for 15 minutes or so, this is a really cheap alternative and it's much easier on your engine.
    [/list]


    Stay warm! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I don't run restrictors in my intake at all. Water flows free from one side to the other.

    I think that his choke is acting up, personally.

    My truck started pretty good yesterday for it being 7 degrees. /forums/images/graemlins/smile.gif Hadn't ran in over a week and started right up. /forums/images/graemlins/thumb.gif
     
  4. R72K5

    R72K5 Banned

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    choke, you need to clean the linkages on side of carb, pass side, and check adjustment of choke, check that its just barely shut when engine is cold in the AM, flip the throttle first though, to set the choke shut first, and watch while its running kicking it down now and then to make sure it drops more and more open, IE slowing up engine RPM,

    do you have electric choke and does the carb have choke pulloff and is it working ? if it has a pulloff then with engine running cold rev it up and make sure the pulloff opens up the choke blade


    sounds liek your choke is just not opening up, either dirty linkages sticky, or bad choke or no power to choke

    its easy to maintain an auto choke, you have to clean and lube the stuff now and then or it will quit working right, usually, its not hard to do, its simple
     

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