automatic transmission drops idle speed very seriously with rebuilt zenith and engine stalls..

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bimoverde

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I know the auto cars do not get much love around here..but i like the easy feel of driving the automatique in the bay area congested traffic..
that said i finally reinstalled the original Zenith carbs instead of the webers that where on the car.. I fully rebuilt them and was able to get them running very well. How ever now when i put the car in drive the middle speed drops way too low for the engine to keep running.. was running well before even if it tended to give a kick when put in drive.
I set my middle speed at 1200 and balanced the carbs.. is there a relay or anything else that needs to be checked or adjusted.. i tried enriching the mixture .. did not make any difference..
FRUSSTRATING>>>>
 
Hi Herve, this is a familiar symptom with the automatic. SO much has to be just right for everything to work. I have found that linkage connections have a huge impact on how everything works. My CSA has twin 32/36 DGAV Webers, and I have fussed over these things for, well, years. I am no expert, but the linkage was binding and once I replaced the bushings with new nylon units, things were better. Also, I have discovered, an external tachometer is more accurate than the dashboard unit. Fun to play with, but there is a limit. Good luck ! ;)
 
the frustrating part is that i have a very stable idle the car rev nicely just as it did before i went back to solexes (this car has less than 55k miles and i wanted to preserve it as original as possible).. i really don't get why changing carbs would influence the transmission load on the motor..tomorrow i will try leaning the carbs(i enriched them to no avail today)..if the transmission had not been working perfectly before i would have suspected the torque converter..there is definitely something i am missing..
 
Over the years, I notice any carb problem usually gets blamed on a vacuum leak. I know you have a good idle, but I wonder if the carb bases are secure, or if even the base of the carbs are true. Perhaps air leak there. Just a thought. I struggled with what idle to set carbs at, because once in gear, the auto does drag the revs down. Further carb balancing as well as using an external tach helped. Good luck!
 
Backup plan: 5-speed conversion.

Paradoxically I discovered latent carb problems after converting from automatic to 5-speed...
 
If I remember correctly, there was a "kickdown" cable on my 72 that ran from the transmission to the bell crank. I think it was designed to cause the auto to downshift if you depressed the accelerator beyond a certain point after the car had shifted up beyond second gear.

If you have one of these, perhaps it is acting on your linkage when you shift the car into gear.
 
thanks..i checked and it does not move when the car goes into gear..it only moves when the accelerator pedal is pressed down.
still can't figure out what the problem is....
 
couple things to report.. the ear valve was wrongly connected to a vacuum port. The carbs were also too rich..
Got the middle down to about 950rpm and now when the car goes into gear, no more issues..carbs are well balanced and the engine pulls nicely...runs actually better than when the webers were on..
Drove the car today for 30 minutes and all is back in order....:):)
 
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