Thread: Engine stalling after freeway

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Hey everyone, love this site, has been the source of some great info in learning to repair all the problems i have run into with my beast over the years......but this is my first post so pls bear with me...

I have a 1967 Mustang Couple, with a standard 289 Windsor, 2 barrell carby, everything pretty standard, usually drives pretty good, but the prob lies after driving on a freeway, when i have to slow back to the lower speeds, unless i pull the choke out when i come to the lights or have to really slow down, the engine will just stall and die, will restart right away but will need a fair bit of choke to keep it going

I dont think its anything major, but my mechanical abilities are based on learning how to fix each new problem arises, so if anyone can give me some idea's on if the carby needs cleaning or retuning etc etc, would be much appreciated!....

Thanks guys...

The temp seems to be ok, its a typical old car, prob does need a new radiator, but the temp is fine when this has happened....as for the gas cap vent....ill have to look into that, wasnt even aware it had one! See im still learning!

Perhaps its a case of your fuel heating up to much due to the lines running close extractors or exhaust tubing or just the heat rising from your inlet manifold. I think its called perculation someone will correct that if its wrong. These probs can be fixed with insulation. Either a fibre spacer under the carb or some form of insulative barrier from other heat sources. At least thats a place to start.

Andy

I'm running into a similar issue with my 55' F100. Stock 223/6, stock fuel tank, lines, mechanical pump, etc. I thought at first it might have been related to the steel vac line from the distributor to the carb being loose, but it's still happening after having tightened up the vac line fittings. It's possible that it might be a heating issue as the rubber fuel line from the pump to the carb runs close to the heater hoses, and around the front of the valve cover between the breather and the upper radiator hose. Although, it has also happened at 2AM on the way home from a music gig near home......not like the hot weather on the way home from Puyallup GG show....

Having a clear float bowl cover, and a clear filter....there's plenty of fuel in the bowl, but there appears there might not be a full load of fuel in the filter...thus....it may be a failing diagphram in the mechanical fuel pump or a failing pump.....I haven't repaired/replaced it as yet, but I'm hoping that will be the issue....

Any other thoughts from the masterminds of mechanical mysteries on something I might be overlooking?

If your vent was clogged, you'd be stalling on the highway after a few miles.

Sounds like you need to adjust your idle speed.
Raise it 100-200 rpm and see how it does.

If it does ok, but the idle is still too fast you'll have to back off the idle and adjust the carb mixture screws.

Its vapour lock. The engine heat is carried away by the car's motion, and when you slow down, that heat remains under the hood, vaporising the gas somewhere. Check line routing , move it away from hot spots. I had a '66 'Tang and had to put an electric pump back at the tank for much the same problem.

Another possiblillity is venturi icing up,,,the faster you move air,,,the colder it gets,,,,when air enters the carburator,,as it drops through the Venturi,, it gains speed and also gets much colder,,,,this could be your problem.
Next time you get off the freeway,,,dont try keep it running,,,just get it stopped safely,,,and get under the hood real fast,,,and get a look down the throat of your carb,,,you may see that the venturi is full of frost,thereby restricting air/fuel flow.

Thunderbucket has a point, I had a slant six and a 2.8 S-10 that did that. Usually did it on a moist, sticky day. Cured it by running a hose from the air cleaner snorkel to the corner of the rad, sucking hot air.