1955 stalling & sputtering

[Mnace01]

Hello all, my wife and I decided to buy a Thunderbird, absolutely love it's style. We've had it for 2 months and since day 1 it's sputtered and stalled when at stop lights in gear (automatic), sometimes stutters around 35 mph too. I've replaced spark plugs, ignition coil, had carb professionally rebuilt by specialist, added a auxiliary electric
Fuel pump before the mechanical one. Heat riser valve was not opening so I tied it open permanently. I'm kind of at a loss now with remedies, any ideas? Thanks

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[zeroroadkill]

Sounds like a fuel delivery problem. Noticed you installed an electric fuel pump in front of the manual pump. It should be able to push fuel through the mechanical pump but be aware if the mechanical pump diaphragm fails or leaks fuel can enter the engine oil. I eliminated the mechanical pump and bypassed it from the electric fuel pump to the filter. I only use the mechanical pump for windshield wiper vacuum. Might want to try that?

 

[Mnace01]

Sounds like a fuel delivery problem. Noticed you installed an electric fuel pump in front of the manual pump. It should be able to push fuel through the mechanical pump but be aware if the mechanical pump diaphragm fails or leaks fuel can enter the engine oil. I eliminated the mechanical pump and bypassed it from the electric fuel pump to the filter. I only use the mechanical pump for windshield wiper vacuum. Might want to try that?

That sounds like a fine idea. Did you just fill the mechanical input/output with threaded plugs than? Also, my electrical system is still 6v, will the 3 psi pump be adequate. Got the 6v pump from Casco.

 

[Ward 57]

Hello all, my wife and I decided to buy a Thunderbird, absolutely love it's style. We've had it for 2 months and since day 1 it's sputtered and stalled when at stop lights in gear (automatic), sometimes stutters around 35 mph too. I've replaced spark plugs, ignition coil, had carb professionally rebuilt by specialist, added a auxiliary electric
Fuel pump before the mechanical one. Heat riser valve was not opening so I tied it open permanently. I'm kind of at a loss now with remedies, any ideas? Thanks

I had the same issue on my '57. Turned out it was the coil resistor. Mine had the ceramic insulator cracked & was making intermittent connections. It is deactivated on starting to get more current to the coil and cut the current through the points when in the run mode. If it's failing it cuts power to the coil when in run mode. You can by-pass it temporarily and see if your symptoms go away or do a continuity test on it while wiggling the wires and contacts.

 

[4VE]

There are some other components that you could try to deal with. Among them are the vacuum advance and hose, points, condenser and the rotor (under the distributor cap). It is one of three things: electrical, fuel or mechanical. Since you have an aux fuel pump, did you replace the fuel filter? You can also check the fuel lines by disconnecting them from the tank and pump(s) and blow them out. The fuel usually contains some water that can precipitate and cause rusting of the lines and tank. This rust can clog the lines. (A Stainless tank is a good investment). A tricky way to check the electric is to get an induction timing light and attach it to the the various plug wires and see if there is an electrical issue. The light should pulse along with the sequence of the spark. Another trick is to look under the hood in the dark for any stray electrical arcing from any wires. You can check the vacuum advance using your mouth to draw a vacuum and look to see if the diaphragm actuates.

 

[Mnace01]

There are some other components that you could try to deal with. Among them are the vacuum advance and hose, points, condenser and the rotor (under the distributor cap). It is one of three things: electrical, fuel or mechanical. Since you have an aux fuel pump, did you replace the fuel filter? You can also check the fuel lines by disconnecting them from the tank and pump(s) and blow them out. The fuel usually contains some water that can precipitate and cause rusting of the lines and tank. This rust can clog the lines. (A Stainless tank is a good investment). A tricky way to check the electric is to get an induction timing light and attach it to the the various plug wires and see if there is an electrical issue. The light should pulse along with the sequence of the spark. Another trick is to look under the hood in the dark for any stray electrical arcing from any wires. You can check the vacuum advance using your mouth to draw a vacuum and look to see if the diaphragm actuates.

Thanks, I did replace the fuel filter, and forgot to mention I also replaced voltage regulator. There was nothing in the fuel filter and I know it's flowing. Also have a carb plate riser installed to raise it more off the manifold. I bought an old school analyzer, but honestly haven't looked into how to use it 🙂. C'mon, I'm only 45 I'm used to plugging into a computer lol

 

[doug7740]

That sounds like a fine idea. Did you just fill the mechanical input/output with threaded plugs than? Also, my electrical system is still 6v, will the 3 psi pump be adequate. Got the 6v pump from Casco.

Since the mechanical fuel pump spec is 4.5 to 5 psi and the volume is 1 pint in 45 seconds or less, I don't think 3 psi is adequate enough.

doug7740
1955 Thunderbird Blue

 

[JRH]

Been having a tough time trying to get my 55 from stalling i was reading on the web about starting the car and take carb cleaner and spray around the intake gasket. If the idle raises momentarily you have a vacuum leak. Well on the passenger side in the front there it is. Hope it helps and fixes my problem.