Priming is not possible when a fuel pump goes bad; this is normally due to a mechanical or electrical problem that needs immediate resolution to restore the right flow of fuel. This can also be due to a blown fuse that prevents the fuel pump from getting power. The status of the fuel pump fuse can easily be confirmed using a multimeter. If the fuse is indeed faulty, replacement is quite easy and inexpensive, ranging between $5 to $20 depending on the make and model of your vehicle.
The fuel filter could be clogged. An obstructed fuel filter might limit fuel flow to the engine, making it impossible for the pump to prime. This involves replacement of the fuel filter, normally situated near the fuel tank or along the fuel line; replacement costs range from $50 to $150, depending on your vehicle’s make. It reduces the efficiency of the fuel system by up to 30 percent, possibly leading to poor engine performance and difficulty in starting.
The electrical problem may be caused by faulty fuel pump relays. A relay regulates the amount of electrical current that reaches the pump. If the relay goes bad, it may not send any power to the pump. This condition can be diagnosed using a relay tester, which tests for continuity. A replacement relay can cost between 20 and 50 dollars. Also, the wiring and connectors have to be checked for rust or any other form of damage that may interfere with signal transmission to the fuel pump.
Severe cases require the malfunctioning of the fuel pump itself. Over some time, a fuel pump has the possibility of wornness, especially in vehicles going over 100,000 miles, resulting in pump failure to prime. The cost of replacement can vary from $200 to $1,000, depending on the make of the vehicle and labor costs, which usually take 3 to 5 hours. This could result in a 20% or greater drop in fuel pressure, thus drastically affecting engine performance.
Air in the fuel lines also creates issues when trying to prime. In most cases, bleeding of the fuel system resolves the issue by getting rid of the trapped air by simply loosening the fuel line or using some sort of special pump that will push it through. Of course, a mechanic would handle this work at a fee, mostly dependent on your vehicle, taking anywhere between $50-$100 depending on time investment.
The troubleshooting of a non-priming Fuel Pump should be conducted in steps, starting from the most frequent reasons, including a blown fuse or a clogged filter, up to the more serious, such as electrical failure or a worn-out pump. In this way, correcting the problem in the shortest time possible enables the vehicle to operate with efficiency and prevents any further damage to the fuel system that may lead to poor engine performance.