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4) But in your facts today you say the fuel pump goes to zero and the car still runs......The fuel pump pressure should not go to zero. it should maintain a regulated pressure, a constant pressure, from the regulator, that the needle seat on the carb regulates demand for.
5) You said the pressure gauge might be wrong, well it might be right as well.
6) you can change the gauge if that is a concern and re-check. So what would cause a electric fuel pump to drop out? one answer is electric problem from the wire feeding the voltage and for the grounds for that pump. Of course bad internal wiring as well. So if this condition happen with a mechanical pump before?
9) when your car heats up, resistance can build up in a wiring circuit, and in your case since the fuel pump PSI drops to zero that is the first place to look.
10) Turning left could cause a loose connection or ground to move or be jostled by the suspension. other places this can happen should be looked at as well.
22) I would start with what that electric pump system requires in the tank, once that is right I would explore the electric to that pump, it should not drop pressure, and just because the car doesn't immediately die is not an indicator necessarily and with a carb the float bowl maintains some gas, so it the pump restarts it mat still run, a modern fuel injected car would die and the pressure in the fuel rail is maintained without reserve.
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