Classic/Antique Car Repair: 1973 satelite custom, Car bucking and stalling when cold


Question
my car died going down the street. It wasn't runnig hot or anything ,but befor than i had a problem with it hesatating intil it warme
d up ,then it would run fine. So i was told to change the fuel pump,no luck. Change plugs no luck. So i chaged out the electronic ignition with no luck. Car only has 70,000miles on it

Answer
Hi Percy,

Nice car, that Satelite. You didn't tell me the engine size, which is always helpful, but what I say should apply to all engines. The following explanation is longer than I intended but I was trying to explain not only the repair but also the hows and whys it happens, and finally how to diagnose it yourself. In my book, this helps you not fall victim to the guessing and parts changing often good components that you find so often today.

The fault you have is most often due to fuel starvation when the engine's cold. A cold engine needs a richer mixture to run, hence you have a choke, etc. When the engine's warm, it needs a leaner mixture to run. These two conditions seem to describe the situation you have including stalling under load. So, what manufacturers have done is provide a method to richen the mixture, particulalrly when cold. The device is called an accelerator pump and it's in your carburator. It looks like a small plunger and is located in a round cavity in your carb. Looking at the linkage on your carb, it usually has a rod running to it and and connects to the very top of the plunger. The purpose of the pump is to squirt additional gas into the engine for smoother acceleratioin under load and particulalry when the engine's cold. If take off the air cleaner with the engine off, and look down the throat of the carburator, moving the throttle cable/linkage on the side of the driver side of the carb. forward, you should see a strong stream or streams of fuel being squirted into the carburator throat. If you don't see this stream of gas thoughtout the travel of your accelerator linkage, you've found your problem. Many times you'll see just a weak stream or a sputtering stream which causes the hesitation and stalling you're seeing when cold. It's also why the hesitation seems to subside when the engine's warm. I recommend you try the preceding test yourself to confirm your diagnosis. Try to find a good mechanic if your not handy yourself because changing the fuel pump will not correct this conition nor will a new electrical ignition module, plugs, etc. becuase this is primarily a fuel problem. The work you did, particulalrly plugs, the car probably needed anyway. But while the other parts you changed may have been helpful, their replacement is far down the list in diagnosing this probem.

The good news is that this is fairly simple to fix. A new accelerator pump is available separately at quality, not big box, stores like NAPA. If you can't get it alone, the pump's included in a carburator rebuild kit for your car, year and engine. In most cases,while you'll have to remove the top cover of the carb. to access this part. But, it also gives you an opportunity to look inside for dirt, misadjustments, etc. If the pump alone doesn't fix the problem, often times the tiny tunnel from the pump to the throat becomes clogged with dirt so then it's best to use the rest of the carb. kit for cleaning and rebuilding the carburator. Try to resist the temptation to buy anther rebuilt carburator at the big box auto store as they're often no better than what you've got. Rather, find a mechanic who understands the old carburated fuel systems. If you don't know of any and don't want to do it yourself, contact your local chapter of the Plymouth Owners Club, Walter P. Chrysler club or local MOPAR club where the experts there can help you find the best souces and even give you tips about driving and maintaining your car. And even if you do fix it yourself, these clubs are invaluable to the old car owner.

Good luck and drop me an update sometime to let me know how you turned out!  

Bob