Stalls when coming to stop light

C

cjc56

Senior Member
Just finished restoring a 56 tbird. everything stock except a Petronics in the dist. Has a holley 4000 tea pot carb (rebuilt by a holley approved tech) Timing set at 6 degrees. Idle (in park) 800. Vac at idle 22 psi. Motor runs great and idles great while in park but when it is put in drive the engine boggs down and dies. Seems to be worst when engine is hot. The engine will start right back up in park. It has a fordomatic trans(rebuilt) with rebuild torque converter.
 
From your post it seems as if you are able to drive the car right? your title says "stalls when coming to stop light"... does the engine die before you come to a complete stop while in drive? your post though it seems that the trouble is "off idle" right? or is both?

FWIW, Y blocks like a whole lot more advance than 6 degrees. The ones I have had in the past always were at double that at idle and ran extremely well with original Fordomatics.

The condition being worse when it is hot makes me think this is fuel related... teapots can be difficult to be made to run well "off idle" if the circuits are not completely clear.
 
If Daniel is correct about stalling at idle, I'll second the initial advance. I'm also assuming you're running the "correct" load o matic dizzy, or have made the necessary mods to the carb (or manifold vacumn) to a late model dizzy. I've had a number of older cars that died when stopping, combination of throttle closing suddenly and torque converter load. Might try a little more idle speed, then look into the carb if that fixes it. The idle /air bleed on the teapot can be tough to do right.

The ethanol fuel seems to be causing a lot of hot run problems in any older cars. Some report less or no ethanol in premium fuel, might be worth the cost of a tank.
 
cjc56 said:
Just finished restoring a 56 tbird. everything stock except a Petronics in the dist. Has a holley 4000 tea pot carb (rebuilt by a holley approved tech) Timing set at 6 degrees. Idle (in park) 800. Vac at idle 22 psi. Motor runs great and idles great while in park but when it is put in drive the engine boggs down and dies. Seems to be worst when engine is hot. The engine will start right back up in park. It has a fordomatic trans(rebuilt) with rebuild torque converter.
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Automatic transmission cars have an anti stall device that mounts on the carb base and the plunger contacts the throttle linkage. When the throttle is released the plunger slows the throttle closing preventing stalling.
Is yours missing or out of adjustment?
Bill
 
I experience a similar thing with the 223 six stock 3 speed. When coming to a stop it died on me, always had to have my finger on the choke knob. It was the carb. Not sure what exactly, but it went away when I got it rebuilt.
 
Thanks for all the suggestions. The rpms begin to decrease as soon as you let off the gas( when coming to a stop). They continue to drop until the engine finally runs so rough that the engine stalls out. I do have a dash pot on the carb and it is working to slow down the fall in rpms. The torque converter is the same one that was on the car originally. It was not modified, only rebuilt by a fordomatic tech. I have also found that on the rare occasion that I can get it to run in gear at a stop, if I hit and release the gas pedal very quickly, it will surely die.

Since every thing on the car is stock, including the carb and dist (has a dual advance, working!) and the timing marks on the damper only go to 20 degrees, do you just guess at the advancing the timing?

I am beginning to think that it has something to do with the carb!!!!!
 
To answer Hot rod reverend, If you are asking does the car stall when you hit the gas, the answer is no. There is no stumble at all once the rpms get back up to about 700. The problem seems to be when the rpms are under 700. If I run the idle rpms (in park) up to 1100 then the engine will not stall when I put it in drive( rpms drop to 700). But that is not practical since the car jumps into gear when shifted.
 
Has the engine been rebuilt? They will act this way when the timing chain is stretched and is very loose, or the camshaft is retarded one tooth. John
 
Since the engine was just rebuilt and the timing chain was new, is there any way to tell FOR SURE if the cam is off a notch without tearing down the front of the engine?
 
Hot Rod Reverend has the right idea.The first thing to try is ,using a timing light,advance the initial timing at idle to 12 degrees.Disconnect and plug the vacuum line to the distributor while setting the timing.Y-blocks run much better and cooler with the timing advanced.
 
It sounds like the torque converter is dragging the engine down. Is there a Lucas product that will make the trans oil slipperier with out screwing up the clutches? Ask some transmission guru's. Lucas has some amazing products.
 
The torque converter is a possibility. I just spent 4+ weeks waiting for a '55 Bird t/c replacement part the trans shop said was bad and would cause the same stalling symptoms.
 
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Thanks for the help. I have reset the timing to 14 BTDC and the engine does not stall when in gear but it idles pretty rough. So the timing was the right suggestion. Now I need to figure out why it is idling so rough. Is this normal for the old tea pot type carbs? I have used carb cleaner and squirted it around the carb to check for vac leaks and the only one I find is around the throttle shaft. But is that normal for these old carbs and should it make it run that rough?
 
cjc56 said:
Thanks for the help. I have reset the timing to 14 BTDC and the engine does not stall when in gear but it idles pretty rough. So the timing was the right suggestion. Now I need to figure out why it is idling so rough. Is this normal for the old tea pot type carbs? I have used carb cleaner and squirted it around the carb to check for vac leaks and the only one I find is around the throttle shaft. But is that normal for these old carbs and should it make it run that rough?
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If you increased the timing from 6 to 14 degrees BTDC, then I assume you had to turn down the idles speed a little bit too. This puts the throttle plates in a different position in relation to the idle discharge holes, and probably needs the two mixture screws adjusted. Using a vacuum gage is best, but can do it by ear for best speed and smoothness too.
A sloppy throttle shaft vacuum leak can be an issue, but if you're car idled good earlier, then I doubt if the throttle shaft is a problem.
 
cjc56 said:
Thanks for all the suggestions. The rpms begin to decrease as soon as you let off the gas( when coming to a stop). They continue to drop until the engine finally runs so rough that the engine stalls out. I do have a dash pot on the carb and it is working to slow down the fall in rpms. The torque converter is the same one that was on the car originally. It was not modified, only rebuilt by a fordomatic tech. I have also found that on the rare occasion that I can get it to run in gear at a stop, if I hit and release the gas pedal very quickly, it will surely die.

Since every thing on the car is stock, including the carb and dist (has a dual advance, working!) and the timing marks on the damper only go to 20 degrees, do you just guess at the advancing the timing?

I am beginning to think that it has something to do with the carb!!!!!
Click to expand...

I would go through the carb and also replace the dashpot, they're cheap enough and takes little time.
 
the dash pot is brand new and adjusted properly. I am thinking more and more that the carb has a issue. I have not checked to see if this carb has a filter/screen just inside the fuel inlet but I plan to do that today. Maybe I have something in it from the new lines/tank. Though the fuel filter on the engine is new.
 
Old gas tanks.. the gift that keeps on giving. Look to see if the inlet filter has picked anything up. I like to put big Holley in-line filters on my cars, I'll be putting one on my '59 Ford in an easy-to-access spot.
 
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