Weird Stalling Issue
Thread Starter
Burning Brakes
Joined: Sep 2006
Posts: 851
Likes: 10
From: Palm City, FL
Weird Stalling Issue
My neighbor has a 68 w/ a 427... has a holly 4bbl carb, 4spd manual.
He showed me something weird that happens. The car starts, warms up fast idle, regular idles, and drives perfectly normal. You go on the highway and drives normal, stop go traffic it drives normal. But if you go on the highway, punch the gas, open up all 4bbl and go to around 110-120 or so, slow down... it still drives normal at this point, but the next time you come to a traffic light, the cars idle slows and slows until it stalls out... it will only stay going if you either play with the gas a bit while stopped, or actually adjust the idle on the carb. He showed me and I have no idea what it is that would cause this.
Even weirder, is that if you let the car cool completly over night... and drive the next day... if you didn't adjust the idle the day before, it will run fine again... if you did adjust the idle for the day before, it idles too high and needs to be adjusted back down.
I never had this happen on my 69.
Any idea?
He showed me something weird that happens. The car starts, warms up fast idle, regular idles, and drives perfectly normal. You go on the highway and drives normal, stop go traffic it drives normal. But if you go on the highway, punch the gas, open up all 4bbl and go to around 110-120 or so, slow down... it still drives normal at this point, but the next time you come to a traffic light, the cars idle slows and slows until it stalls out... it will only stay going if you either play with the gas a bit while stopped, or actually adjust the idle on the carb. He showed me and I have no idea what it is that would cause this.
Even weirder, is that if you let the car cool completly over night... and drive the next day... if you didn't adjust the idle the day before, it will run fine again... if you did adjust the idle for the day before, it idles too high and needs to be adjusted back down.
I never had this happen on my 69.
Any idea?
Thread Starter
Burning Brakes
Joined: Sep 2006
Posts: 851
Likes: 10
From: Palm City, FL
Originally Posted by Jud Chapin
Have you checked to make sure the linkage from the accelerator pedal to the carb is operating freely?
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Originally Posted by genuine1980
It's something we checked, even though I doubt it would change from what I am describing is happening.
Thread Starter
Burning Brakes
Joined: Sep 2006
Posts: 851
Likes: 10
From: Palm City, FL
I am 100% sure there is no binding linkage... it is something we checked.
Anyway, why would it only happen after driving at high speeds and no other time?
As I said the car will run perfectly and contiue to do so... until and only after we really open it up and bring it to a high speed. We where out this morning driving noramally, side roads, highway, drove around 80 on the highway... everyting was fine.
Anyway, why would it only happen after driving at high speeds and no other time?
As I said the car will run perfectly and contiue to do so... until and only after we really open it up and bring it to a high speed. We where out this morning driving noramally, side roads, highway, drove around 80 on the highway... everyting was fine.
Intermediate
Joined: Sep 2006
Posts: 26
Likes: 0
From: Madison Heights MI
Originally Posted by genuine1980
Anyway, why would it only happen after driving at high speeds and no other time?
Things expand, clearances change. I had something like that happen on an '84 Camaro. The throttle would bind up when hot and would not want to open.
It could be that the automatic choke is closing after WOT situations. Does it appear to be flooded after it stalls?
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Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Couple of ideas
IMHO, if the linkage is binding, it would seem it should hang at a higher than normal idle.
Since it's a Holley, I'd pull the float bowls and check to see if the floats still float. Even the brass floats can leak and fill, the plastic (or whatever they are) can become saturated. While the float bowls are off, change the power valve. Put it all back together, leak check and adjust, and give it a try.
Since it's a Holley, I'd pull the float bowls and check to see if the floats still float. Even the brass floats can leak and fill, the plastic (or whatever they are) can become saturated. While the float bowls are off, change the power valve. Put it all back together, leak check and adjust, and give it a try.
