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  1. #1
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    Engine falter

    My car is 1976 Chevy Impala.
    Recently, a strange thing happened while the engine was idling and my foot on the accelerator pedal and depressed about an inch and without warning the engine began to falter , the ammeter needle dropped almost all the way down, akin to turning off the ignition key for a moment, then turning it back on. Why did that happen, anyway ? Something to do with the carburetor, choke mechanism, or what ? Got me worried and mystified. Any way to find out on this forum.
    My mechanic says he's too busy to check for the rest of 2014.

  2. #2
    Administrator Ken's Avatar
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    Hi, Chevy.

    Is the problem repeatable?
    Does it heppen every time or is it random?
    Does it happen under certain weather conditions?

    There are many possibilities to consider.

    It could be fuel pump, carb icing, loose wiring connection, fuel contamination, temporary fuel blockage, etc., etc.

    Did the fault clear itself or were you able to clear it by revving the engine perhaps?

    More info please.

    Ken.
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    Ken.
    Wolds Bikers, Lincolnshire, England.

  3. #3
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    >> Is the problem repeatable ? Yes
    >>Does it happen every time or is it random? Random
    >>Does it happen under certain weather.. ? No

    >>Did the fault clear itself? Yes, definitely. The needle goes back to normal, but returns to slightly abnormal.


    To perform the test, I idled the engine continuously for about 27 minutes keeping my eyes on the needle, the ammeter needle, I suppose.

  4. #4
    Senior Member grouch's Avatar
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    The ammeter is only showing a result, not a fault. When the engine stumbles, it slows down and makes less current. The ammeter measures the current flow, ergo, less current, lower reading. Does your car have points or electronic ignition? If it's points, you probably need a tune up. If it's electronic (this was built when all the car companies were going with HEI) you may need a tune up.

    If the cap and rotor have been on there a while, I'd replace them. I'd also pull the spark plugs and look at them. With HEI, you can go quite a while between changing them. If you have points, you need to replace them twice a year. You also have points and condensor to replace.

    One thing you can do is wait until dark and find a place away from lights. The darker the better. Now open the hood with all the vehicle lights off. If you see sparks or phantom flashes sliding along the plug wires, you need new ones. I suspect you just need a tune up from age.
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  5. #5
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    My car has HEI. As for the plugs, I hardly drive the car, maybe 10 to 15 miles per week.

    The way the car is behaving, (read post #1) I first suspected a new fuel filter should fix the problem, (No ?)

    Edit:
    Current odo reading 58010.
    Plugs/wires replaced at 51376 mi. in 2007
    Carb o/haul 51107 mi. in2007

    Tune-up 47929mi. in 2004
    Last edited by ChevyMan; 12-24-2014 at 03:52 AM.

  6. #6
    Administrator Ken's Avatar
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    Chevy, ten to fifteen miles a week hardly gets the plugs hot enough to burn off the contamination from the previous run and the 'choked' start fuel regime. I would suggest taking the car for a good, high speed, thirty to fifty mile run to clean the plugs up and boil off any acid and water in the oil. Grouch's suggestions of checking out the ignition electrical components and giving the car a 'tune up' would be a good precursor to a nice long run which would also help clean up the combustion chamber and the exhaust system. Cars that are little used, like yours, require more frequent attention than cars that are regularly given good long distance commuting runs.

    Ken.
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    Ken.
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  7. #7
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    [QUOTE=Ken;139506]Chevy, ten to fifteen miles a week hardly gets the plugs hot enough to burn off the contamination from the previous run and the 'choked' start fuel regime. I would suggest taking the car for a good, high speed, thirty to fifty mile run to clean the plugs up and boil off any acid and water in the oil. <<

    Would occasional fast idling in place help, instead of taking it on the highway? I'd hate it in case something goes wrong and the engine dies , requiring me to call a tow truck.
    I idled it for about 35 minutes, simulating increasing the speed time to time and several times the engine wanted to die but never did but it did decrease the RPM slow enough to turn the GEN light on momentarily. I suppose it's safe enough to go shopping a mile away and back. What do you think?.

  8. #8
    Senior Member grouch's Avatar
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    [QUOTE=ChevyMan;139507]
    Quote Originally Posted by Ken View Post
    Chevy, ten to fifteen miles a week hardly gets the plugs hot enough to burn off the contamination from the previous run and the 'choked' start fuel regime. I would suggest taking the car for a good, high speed, thirty to fifty mile run to clean the plugs up and boil off any acid and water in the oil. <<

    Would occasional fast idling in place help, instead of taking it on the highway? I'd hate it in case something goes wrong and the engine dies , requiring me to call a tow truck.
    I idled it for about 35 minutes, simulating increasing the speed time to time and several times the engine wanted to die but never did but it did decrease the RPM slow enough to turn the GEN light on momentarily. I suppose it's safe enough to go shopping a mile away and back. What do you think?.


    Maybe, but I doubt it. The first thing I would check would be inside the distributor cap. Being near the ocean (on an island everyplace is near the ocean) you may have corrosion inside the distributor cap. You say you replaced the plug and wires in '07. 8 years is long enough for a hairline crack to form in the cap. It's just plastic after all. If it WASN'T replaced, it's way past time. Moisture getting in because of a crack can cause arcing and this wil show up as a falter like you describe. If you replace it, be sure to get one with brass or copper electrodes. These can make better connection and get a hotter fire to the plugs.
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  9. #9
    Administrator Ken's Avatar
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    [QUOTE=ChevyMan;139507]
    Quote Originally Posted by Ken View Post
    Chevy, ten to fifteen miles a week hardly gets the plugs hot enough to burn off the contamination from the previous run and the 'choked' start fuel regime. I would suggest taking the car for a good, high speed, thirty to fifty mile run to clean the plugs up and boil off any acid and water in the oil. <<

    Would occasional fast idling in place help, instead of taking it on the highway? I'd hate it in case something goes wrong and the engine dies , requiring me to call a tow truck.
    I idled it for about 35 minutes, simulating increasing the speed time to time and several times the engine wanted to die but never did but it did decrease the RPM slow enough to turn the GEN light on momentarily. I suppose it's safe enough to go shopping a mile away and back. What do you think?.
    In my experience nothing beats a proper run, with the engine working hard, in the car. Carry out the checks that Grouch recommended, then, if everything checks out take the car for a good run. You may find that you have a much sweeter running car afterwards. Don't get worried if after about ten hard miles you see clouds of black smoke and crud coming out of the exhaust as the rubbish gets burnt off.

    Ken.
    Die dulci fruimini!
    Ken.
    Wolds Bikers, Lincolnshire, England.

  10. #10
    Senior Member grouch's Avatar
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    Sakes, here I am looking at 60 and I now feel like a young pup. My mother was active until she passed away at 93. She drove until she was 90 but managed to stubborn herself into a broken hip and that was the end of her driving. Her aunt Clara lived to 98 and drove until she was 96. The only reason she quit was she needed the moeny and sold her car.
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