Coil to blame?

gregthall

gregthall

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I am leaning toward the coil as from what I have gleaned from the site. I know I see the threads that always start with this same disclaimer..."I read for hours but couldn't find the exact same symptoms, only similar" Well, here I am. I have replaced everything ignition except the coil. Which up until I did the points, I had not experienced the problem of sudden cut-out and lack of responsiveness and bucking.

I have Retimed, balanced carbs, new plugs, wires, points, replaced ballast resistor (which the ceramic was bifurcated).

Symptoms: Car starts and idles wonderfully. Get on the road and she's perfect. There is even power to go thru the gears get into fourth and about 1 mile down the road I can feel the power fading. Gradual fade at first, then no power when I hit the gas. Pull over and it stalls. I can get it back going, but it is definitely a different car. IF I can get it back up to 40mph and keep accelerator steady, I get bursts of power, like someone is flipping a light switch on and off, until alas, it dies again. Pull over wait a minute or two and I can get it going again, but still not like the initial drive. Finally get it up the 750 ft elevation climb the the house bucking and limping home (good times). It will sit for a few hours and then start right up and sound and drive great for a mile and the symptoms are the same.

Thanks in Advance. Greg.
 
gregthall said:
I am leaning toward the coil as from what I have gleaned from the site. I know I see the threads that always start with this same disclaimer..."I read for hours but couldn't find the exact same symptoms, only similar" Well, here I am. I have replaced everything ignition except the coil. Which up until I did the points, I had not experienced the problem of sudden cut-out and lack of responsiveness and bucking.

I have Retimed, balanced carbs, new plugs, wires, points, replaced ballast resistor (which the ceramic was bifurcated).

Symptoms: Car starts and idles wonderfully. Get on the road and she's perfect. There is even power to go thru the gears get into fourth and about 1 mile down the road I can feel the power fading. Gradual fade at first, then no power when I hit the gas. Pull over and it stalls. I can get it back going, but it is definitely a different car. IF I can get it back up to 40mph and keep accelerator steady, I get bursts of power, like someone is flipping a light switch on and off, until alas, it dies again. Pull over wait a minute or two and I can get it going again, but still not like the initial drive. Finally get it up the 750 ft elevation climb the the house bucking and limping home (good times). It will sit for a few hours and then start right up and sound and drive great for a mile and the symptoms are the same.

Thanks in Advance. Greg.
Click to expand...


Might be helpful if you started with a brief description of the patient. A medical history may not always provide incite, but you never know. Mileage? Modifications? Carburetors original or replacements? Recent work performed immediately prior to problem?

A dying coil and/or condenser can mimic an ailing fuel pump. An ailing fuel pump can mimic . . . an ailing fuel pump. There is nothing particularly special about the Bosch coil. Virtually any traditional 12V coil will work in a pinch for testing your own hunch. You mentioned points, so have you replaced that condenser or ensured the pigtail is properly grounded?

I am guessing your fuel pump is dandy, but that it just a guess. If it is borderline sucking wind and your carbs have floats that are improperly adjusted (too low) is it possible you are occasionally running dry? Same approach respecting other fuel restrictions, as mentioned by others.
 
patient: '71 2800 stock, no mods, zenith carbs.
suck is good I had junk in the previous fuel filters, seems to have been minor junk.

update to the post: I was showing my kids what a coil was and what it did. As I was showing them, the wire broke at the boot. Brand new wires. So when I get back today I am going to throw on a heavier duty coil wire and another coil I have laying around. Fingers crossed
 
I remember you said you bought your car off a lot. Was it sitting for quite a while before that? Did you clean out the fuel tank and fuel lines when you first bought the car?
 
cast my vote for the carbs. my car did the exact same thing when i first bought it. Had stock carbs for short period before switching to triples. Never spent the time to diagnose what exactly was wrong with them but never had the problem again after the switch.
 
I would think if it were the carbs, the plugs would have told some story. How did they look, lean, rich or ok? Also wrt temp, other than the automatic choke on the Zeniths, the thermo switch (kind of a cold start valve) also depends on temp. If this is stuck open, car will run rich when warm.
 
She's alive and kicking. Turns out, the Tee to the carbs was made of a cheap flimsy plastic, that I inadvertently ratcheted down too tight restricting fuel flow in and out. It was flowing, but only enough for a mile or so. Brass Tee in there now damn it. Now, had I found the problem before I tore everything else apart--it would have been a quick simple fix. But I basically replaced, cleaned and gapped everything-- then I discovered the problem. Upside is, it runs great! No spitting or popping when I down shift. It idles smoothly and once again it is a pleasure to drive, air-conditioning not withstanding. Drove it out to New Hope today where I met Steve O'Neill and Mike Maguire and his wife. Thanks again for the help guys.
 
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