Bad Fuel Pump Relay Symptoms. Learn the warning signs of a failing fuel pump relay. This video explains symptoms like engine hesitation, hard starting, rough idle, losing power, and trouble codes.

The fuel pump relay is a crucial bridge between your vehicle’s electrical circuits and the fuel pump. When you turn the key to start the engine, the fuel pump relay closes to provide 12volt power from the battery to the intank fuel pump, allowing it to pressurize the fuel rail with up to 60 PSI of fuel pressure. This allows the fuel injectors to spray fuel into the engine so it can run. Once the vehicle is running, the relay stays closed to keep the pump flowing.

A faulty fuel pump relay affects the electrical power supply to your fuel pump, which can cause all sorts of performance issues. Diagnose relay problems before small driveability issues lead to full engine stall or nostart.

What is included in the video:
1. Intro to fuel pump relays and how they work
2. Symptoms of a failing fuel pump relay
3. What happens if the fuel pump relay fails completely
4. Why fuel pump relays fail over time
5. Replacement parts cost $1520 USD.

Why Fuel Pump Relays Fail
There are two common reasons fuel pump relays eventually fail after years of cycling on and off:

Heat and electrical overload killing internal components over time. The contacts essentially wear or melt away. Newer solid state relays avoid this issue and last longer.
Low voltage from a failing battery or charging system prevents the relay from closing fully. The fuel pump is unable to pressurize without full 12+ volts. Critical systems like ABS, stability control and variable valve timing stop functioning as well until voltage is restored.

Disclaimer: This content is for educational purposes and should not replace professional advice. As an experienced mechanic, I aim to provide helpful insights, but I'm not liable for any damage or issues arising from the application of this information. Always consult a qualified mechanic for specific vehicle needs. Viewer discretion and responsibility are advised