oldsonharmont

Any ideas what might cause an engine (455) to stall after deceleration? Took the SX out for cruise tonight and had it stall on me twice when I came to a stoplight. It cruises nicely at 60 mph, but dies after you let off the gas.
(fuel filter or pump perhaps?)
p.s. Just did my own tune-up: points, plugs, condenser, cap and rotor... it purrs like a kitten.

Rickman48

There shoud be a 'vacuum pot' that engages sightly during high vacuum sequences. such as deceleration.
It's on the front of the linkage, and sometimes needs a squirt of WD-40, if the vacuum hose is good!
I'm not sure of exact adjustment procedures, 'by the book', but I'm sure others will chime in.
Could also be wrong float height in the carb, sticking needle and seat, or too low idle speed.
I check fuel pump and fuel filters by going to the upper RPM limit while driving in 1st gear - bad pump or partially clogged filter will cause a 'flat spot', and not accelerate any higher!

72 w29 all green

Did the engine have this stalling problem before you performed the tune-up?

oldsonharmont

No problem before the tune up, but I did adjust the air fuel screws to make the mixture a little more rich. I also think my dash pot is either broken or missing, so maybe that has something to do with it.

Rickman48

If you use a vacuum guage on the advance port before adjusting mixture, you may be shocked at the difference in both performance and mileage!
Get the highest available.
Check your timing after!

oldsonharmont

I'm still having the stalling problem sometimes at cruising speed or even at a stoplight, but only after the engine has warmed up. Checked the idle speed and air/fuel mixture several times, but I'm still stumped with this. It feels like it's running out of gas when it stalls. Do I need to look into a carb rebuild (Qjet), or could the fuel pump be getting weak.

oldcutlass

I would recheck my dwell and timing first! Then I would readjust my idle fuel mixture on the carb. I adjust my carb with a Tach (my personal choice), as I find it easier to adjust for highest RPM versus highest vacuum on a jumpy gauge. Adjust the idle mixture screws c/w until the engine wants to stumble and then back them out until you see the RPM reach its highest level.

I do it 3 times, each time re-adjusting my Curb Idle speed, and then fine tuning my air fuel mixture. After the 3rd time I then turn both screws in 1/8 of a turn. Please note, if your running any type of temporary fuel additive and /or cleaner you will have to repeat this process again when it is gone.