Here's why:
* Location: External fuel pumps are often located lower in the vehicle, where they are better protected from direct heat from the engine.
* Cooling: Many external fuel pumps have some level of internal cooling.
* Other Heat Sources: More likely culprits for vapor lock are the fuel lines running near hot engine components, a poorly ventilated fuel tank, or a fuel tank that's been exposed to excessive heat.
If you're experiencing what you suspect is vapor lock, the external fuel pump itself is a less likely suspect than other parts of the fuel delivery system. You should investigate:
* Fuel lines: Check for fuel lines that are routed too close to the engine or exhaust manifold.
* Fuel tank ventilation: Ensure the tank's vent is not clogged.
* Fuel tank location: Is the fuel tank excessively exposed to heat?
If the fuel pump IS excessively hot: This could indicate a problem with the pump itself (internal failure leading to excessive friction and heat generation), or a wiring issue causing excessive current draw and overheating. But even then, the heat generated by the pump would be more likely to cause the pump to fail than create vapor lock in the rest of the system.
In short, while a faulty fuel pump *could* contribute indirectly to a vapor lock situation, it's rarely the direct cause. Focus your investigation on other parts of the fuel system first.
