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This problem is driving me nuts. while driving my '50 standard eight the engine will just stop. It happens while sccelerating around 43-47 mph, in second or third gear. The car is at normal operating temperature as well. After the engine dies, it won't restart by 'popping' the clutch. It will only restart after letting the car sit for a few minutes.

I did change the fuel filter (which was old and had some contaminants). I also drained my fuel tank noting that a little bit of brown came out at first (not much) otherwise it was clean fuel.

There is a electric fuel pump mounted near the tank. I could hear it working at first, but when I got the cat home, it wasn't working. I have since bypassed the electric fuel pump and have tested the car with the overdrive locked out. The engine didn't die, but there was a noticable dropout at 45 mph under acceleration.

Any help from you is, as always, extremely valuable.

Does the engine just die or does it stumble like it is running out of fuel.

If fuel, if the mechanical fuel pump is still in and fuel still flows thru it, what is the condition of the screen inside the bottom cover and sump. If that is not a possibility, how is the vent in the gas cap. Another remote possibility some have experienced is debris in the tank moving around and blocking the fuel intake. When engine quits it floats away. With an electric pump, probably not as likely unless the electric pump also stops long enough to break the suction.

If it just quits suddenly, many have had issues with coils overheating and quitting. After current stops and they sit and cool for a few minutes, all is well again. Same could happen if capacitor is acting up when hot.

THe drop off of power at 45 mph is a clue. Does i make a kind of a pup-pup-pup-pup sound just before it dies??? Try a KNOWN good coil and condenser first that's the easiest. OR REMOVE gas cap if vent is plugged.

If those fail to cure the problem then very likely it mite be a needle and seat problem especialy if needle is "rubber" tipped and distorted due to ethanol or a bad pump.

If it were the condenser, it could gradually begin to run poorly from idle throughout the operating RPM range. Eventually it wouldn't start at all.

Old, weak coils can fail after getting hot, and function again after cooling. But it takes an hour or two to cool down a coil.

Sounds like sediment in the tank to me. (IMHO).

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The engine just dies...no puttering or gasping, just stalls.
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The mechanical pump is still attached and fuel flows thru it. I haven't checked the condition of the screen or sump, yet. I have ordered a rebuilt one from MM, tho.
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The coil was just replaced, I'd hope it is ok, but you know how that goes.

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I'll check the vent on the gas cap also.
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I hope to find out more as I check things out. One thing tho, would the OD kickdown switch have anything to do with this since it seems to happen when the gas pedal is pushed tot he floor?

Isn't there some kind of ignition cut out that occurs momentarily the OD kicks in or out? Perhaps something has gone astray there.

The OD switch temporarily kills the engine so that you can disengage OD. If wired wrong it might give you this problem.
Make sure you don't push accelerator to floor when accelerating - accelerate gradually and see if problem disappears.

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Most definitely. Your OD relay may not be functioning properly. The kickdown switch should kill the ignition momentarily. But the engine shouldn't die. When it happens, you should check the ignition and see if you have juice to the coil with the key on. If not, possibly the OD relay is sticking.

One thing tho, would the OD kickdown switch have anything to do with this since it seems to happen when the gas pedal is pushed tot he floor?


It could if you have a problem in the solenoid or a grounded wire or it's staying in OD. Your 50 should have an R11. If not in OD, the solenoid should be out and it's ign shorting contacts open. While pushing down on accel will close the kickdown switch, the solenoid contact should be open so no connection will be made to ground and engine should keep going. If the solenoid contact is closed or wire to them grounded, then yes the engine will die -- but you should be able to restart it without having to wait -- unless something is hanging up or the solenoid is staying energized.

If in OD, the solenoid will be energized and ign contact will be closed. As soon as you hit the kickdown, coil should ground out but simultaneously solenoid should drop out and almost immediately open those contacts again so the engine just misses a beat or two. If the solenoid is slow in retracting, then the engine could die but you should be able to restart it again unless the solenoid is really hanging or staying energized.

One way to prove whether that is the problem. Remove one of the wires on the kickdown switch that is connected to the set of contacts on the top pair -- ie the ones far away from the plunger. That way, the ign ground circuit from solenoid will be interrupted so the coil should never see a ground-- although the OD may not drop out readily without the torque of engine removed momentarily. You could also remove the fuse to positively keep it out of OD and see if that resolves the problem -- although if a solenoid contact or grounded wire problem, would still be evident.

If by some chance there is only 2 terminals on kickdown sw, then you have an R9 and ign cutout circuit gets a bit more complicated.

Holy Cow! I thought the TL system on my '56 Exec was complicated ;) Let me try and decipher this OD and get with y'all.