1966 galaxie weird problem - Ford Muscle Forums : Ford Muscle Cars Tech Forum
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post #1 of 5 (permalink) Old 08-23-2019, 09:40 AM Thread Starter
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Location: Denver Colorado
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1966 galaxie weird problem

Hello all! Lately my daily driver has been acting up. It is a 1966 Ford Galaxie 500, with a 390 and c6 automatic transmission.
For those who dont want to read:

-sometimes engine idle goes way down when slowing to a stop (400rpm)
-at highway speeds, car seems like its randomly slowing itself down (almost like its engine breaking or something)
-get off freeway and idle will drop way down (like its stuck in 3rd)
-hard to start when it dies due to low idle

Just yesterday I drove the galaxie to the store with absolutely no problems. On my way back, the motor would idle way down as I came to a stop (around 400rpm, almost like it is stuck in 3rd gear). And when i gave it gas to accelerate, it would kind of accelerate for a second, then would like kick into gear and go. The next time I came to a light, the car just died in the middle of a busy street. Took me a good 5 minutes of on and off cranking to get it started again. Pulled into a lot and let it sit for 15 min. After 15 min, it drove the rest of the way like a new car. This problem only occurs sometimes, but lately seems to happen more often.
At highway speeds after about an hour or so of driving on the highway, the car will randomly start to slow down, almost like its engine breaking except the rpms stay pretty constant. This "slow down" will last anywhere from half a second to 10 seconds. Sometimes if I let off the gas slowly then re-apply the gas pedal, the car will kind of engage back into drive again and I can catch up to speed.
Hopefully I gave you guys enough information, and sorry for the long post. Just trying to figure this out so that I can drive my car again. Thank you!
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post #2 of 5 (permalink) Old 08-24-2019, 10:23 PM
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Location: San Francisco .Calif
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Re: 1966 galaxie weird problem

could be exhaust blockage..

a vacuum gauge can be helpful in diagnosing ...

heres how to to interpret gauge.. http://www.secondchancegarage.com/public/186.cfm

look at senario #14 for example...

%201964%20Galaxie/?action=view&current=09-03-10_1408.jpg Lars...
64 galaxie 500 2dr fastback...390 4v, Bendtsen adapter, maddog's stage3 700R4 trans,3.70 Posi..far from perfect but getting there...

Last edited by RAGGAREN; 08-24-2019 at 11:53 PM.
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post #3 of 5 (permalink) Old 08-25-2019, 10:32 AM
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Location: Jacksonville, FL
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Re: 1966 galaxie weird problem

Had some of same problems after new intake and carb installed on FE 352 in 65 convertible. Same type issues. So, rode around to get up to engine op temp and made sure I got off interstate close enough to home to have it die, if destined, in drive. Vapor lock. So, had to guess that on new intake and carb mechanic rerouted gas line too close to intake and engine. Partly true. Long tube headers, alum intake and carb means motor runs "cooler" ... but by heat transfer to air. Under hood. Making under hood heat enough now to boil 10% ethanol mix. Have to buy non-ethanol gas now. At least until I install heat shield to fuel line. Installed phenolic spacer on carb but not enough size and room with new intake and carb to be totally effective against heat transfer. Also bought new double snorkel air intake box. Also purchased OEM 6 blade fan (used) to help with air exchange. Bottom line - old addage: Make cheap adjustment[s] first. Most solutions are compound and not singular. Guard your wallet.

BPayne 65 Galaxie Convertible
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post #4 of 5 (permalink) Old 08-26-2019, 02:54 PM
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Re: 1966 galaxie weird problem

I've had similar issues when my FE gets hot. Fuel would boil out the vent tubes into the intake. Would just slowly die while driving then wake back up, would do this until it cooled down. If I shut it off I would have to do WOT starts to clear the gas.

Lowering the floats helped reduce the amount of times it would do it. Putting a spacer on to reduce the heat next.


'63 Galaxie 2-DR Box Top, 447FE - C6
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post #5 of 5 (permalink) Old 08-29-2019, 05:59 AM
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Re: 1966 galaxie weird problem

Sure sounds like a fuel delivery problem. When the engine won't start, have you tried adding gas directly to the carb to see if it will then kick over?

Lately I've been hearing about "vapor lock" problems that are caused by ethanol boiling and creating bubbles in the fuel line. What's the temperature like in Denver when you're having this problem?
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