Engine stalls

brother has a 1973 Duster, at different times after stopping at a light the motor stalls when he starts to press the gas, then motor will not re-start, he’s had it towed 3 times and after it gets to the shop it will start and the shop says everything is ok. any input would be great.

When the gas pedal is depressed, the throttle position sensor (tps) moves (on the throttle body) and sends a signal to the engine computer. This signal tells the engine computer that the throttle has been opened this much. The engine computer orders the fuel injectors to spray more fuel. If the gas pedal is released, the fuel injectors are ordered to spray less fuel.
The tps wears at idle position and just off idle, the most. This can cause stumble. Poor fuel injector spray can also add to the stumble. Use a fuel injector cleaner in the gas tank. Use a MAF cleaner and a throttle body cleaner. If the spark plugs have been in a while, change those.
The crankshaft position sensor (cps) is often blamed for stalling and no-starts. When the engine gets hot, and the cps gets hot, the cps can start to miss-function. When the engine and cps cools, the cps becomes good, again. The cps can be checked by removing it, placing it in pot of hot water, and monitoring the cps resistance (with a multimeter) as the water is heated. If the resistance suddenly changes, or the circuit opens, the cps is faulty.

This would apply to a 1993 Duster, if there were one, which there isn’t. This looks like a case of the right answer, but, the wrong question.

How does this info apply to a 1973?

Geez! 73 Duster?

Maybe accelerator pump in the carb? Vacuum advance weights/springs in the distributor?


You meant mechanical advance weights/springs, right? And I’m with you on the accelerator pump, that’d be what I’d look at first.

Thanks for the replies. Brother did not tell me that the engine would stall when he would step onthe gas, I replaced the coil and resister last week and everything was fine, he drove it 4 or 5 days and it stalled again and would not start, he called me and it took me about 20-30 min. to get to his location, pulled a plug wire to see if there was a spark, I told him to crank the motor it started and ran fine.not sure what you mean about weights/springs? thanks agaim

Based on your description of the problem I would lean towards an ignition module failure. It is quite common for them to fail when hot then work again after cooling down. Usually if you unbolt it from the firewall and look at the back side you will see signs of shorting to ground or internal overheating. They run about $30.00 at the parts store.

Thanks Dartman, will check it out, jim

Consider adding a can of SEA FOAM to the gas it is a great cleaner an may stop the stalling.

shadetree51, what is SEA FOAM and where to get it. thanks jim

Does it only do it when it’s hot? It might be the dreaded vapor lock.