A failing pump relay affects your vehicle’s capability to pump fuel, which avoids it native starting. If you space not maybe to fix or replace the fuel pump relay immediately, you have the right to bypass the relay to have the ability to use your car. Keep reading to learn how to jump a fuel pump relay.

You are watching: How to jump a fuel pump relay

Is it safe to bypass a fuel pump relay?

Before discovering the process of bypassing a bad fuel pump relay, let’s discover how a fuel pump relay works—the fuel pump relay strength the fuel pump, i beg your pardon is supplies by the vehicle’s powertrain regulate module. Once you turn on her car, the PCM turns on the fuel pump by energizing the fuel pump relay.

The fuel pump relay climate closes that is circuit, allowing the fuel pump come pump fuel into the engine. Once the fuel pump relay is damaged, that is can not to finish its circuit, thereby avoiding the move of power to the fuel pump.


The fuel pump relay additionally acts together a timer because that the fuel pump. It features a timer the pre-pressurizes the fuel mechanism when you revolve on the car. Bypassing the pump relay can lead come fuel gift pumps in ~ high pressure.

Check this too: What is Vapor Lock? just how to settle it and Avoid the Altogether

This can finish up damaging contents of her car, such together the fuel pump. As such, that is no advisable to drive the vehicle with the bypassed fuel pump relay. A damaged fuel pump is more expensive to change than addressing or replacing a fuel pump relay.

How to jump a fuel pump relay

Jumping the relay way diverting strength via an electrical conductor indigenous the relay directly into the fuel pump. Every you need is a metal conductor to deliver the electric existing from the PCM come the fuel pump.


Steps because that jumping the fuel pump relay

Ensure your automobile is parked on level ground and also before you get started.Then open up the hood and also look because that the relay center. The is usually situated on the right side the the engine compartment, behind the driver’s next headlamp.The pump relay is in a black color plastic box that has all the vehicle’s relays.Remove the cover from the under-hood relay center.Use the diagram on the sheathe to locate the fuel pump relay.Then eliminate the 4-pin fuel pump relay from the relay center.Take a 5-inch size of small-diameter copper wire and also strip approximately 1/2 customs of the insulation from each finish with a wire stripper.Insert one finish of the copper wire right into the upper-left pen slot that the 4-pin receptacle wherein the fuel pump relay plugs into the relay center.And insert the other finish of the wire into the lower-right pin slot of the 4-pin receptacle whereby the fuel pump relay plugs into the relay center.Then rotate on the vehicles and also see if the works.If both ends of the cable are appropriately seated, the fuel pump will turn on.

How come tell if a fuel pump relay is bad

In most cases, civilization do not realize their fuel pump relays space damaged until the automobile refuses to turn on. Right here are some simple ways come diagnose a poor fuel pump relay;

The examine engine light is on.

When the fuel pump relay starts failing, the fuel push may obtain affected, i beg your pardon in turn reasons the fuel pressure sensor to note a wrong value. The ECU will save a trouble password for the failing fuel pressure resulting in the engine irradiate to rotate on.

Additionally, a faulty pump relay may additionally lead to a voltage spike in the relay. This is as result of a swollen fuse, shorted fuel pump, frayed wiring, or a puffy circuit. The ECU will interpret the voltage analysis as one error code and also cause the engine light to rotate on.

Rough acceleration

A damaged pump relay will affect the fuel pump’s pressure, i m sorry affects the quantity of fuel gift pumped right into the combustion chamber because of this acceleration may get impacted due come the intermittent fuel injection.


Stalling or idling engine

Damaged soldering ~ above the fuel pump relay may influence electrical connectivity. The power gave to the fuel pump will, in turn, it is in inconsistent. This may bring about intermittent fuel supply resulting in a stalling or idling engine.

No noise indigenous the fuel pump

The fuel pump produce a whirring noise when you revolve on the ignition. This is due to structure fuel press in the fuel rail. A quiet fuel pump is a sign of a failing fuel pump relay together the relay timer is not regulating the fuel pressure.

The engine is dead

This is the ultimate sign of a failing fuel pump relay. An incomplete circuit will stop fuel pump operation, thereby avoiding the engine from beginning due to absence of fuel in the burning chambers.


Longer beginning time

Cause the failing circuit, which might take a while to complete or get completed intermittently, affects fuel pressure. This method the engine will take time to get sufficient fuel to start the car.


High mileage

Lack of fuel press regulation might lead to raised fuel injection into the engine, leading to greater fuel consumption.

The car dies while you space driving.

As a an outcome of disrupted fuel it is provided to the vehicle’s engine.

Fuel Pump Relay Diagnosis

This process helps to determine if over there is electric continuity.

See more: Snap On Pry Bar S - Snap On 4 Piece Green Handle Pry Bar 8 Inch

Locate the fuse box and locate the fuel pump relayLift it and check under it because that the number 30, 85, 86, and also 87. If you find these numbers, you deserve to put the fuel pump relay back.Put the relay ago so you have the right to reach the pins through a multimeter while friend cycle the ignition.Turn on the ignition and check pen 87 with a multimeter. Voltage method the relay is working. Intermittent voltage means bad relay circuitry.If you perform not get voltage, inspect to see if you will get continuous voltage on pen 30 with the ignition on. If friend don’t gain voltage, there can be a damaged fuse.Ensure friend have constant voltage on pen 85 and pin 86. They need to be base from the engine regulate unit as soon as you turn on the ignition.If friend have any kind of continuity problems, eliminate the situation from it to inspect for any kind of bad soldering.Resolder the relay if you find any type of problems.

Check this too: how To element A Fuel Pump after Running out Of Gas

Fuel Pump Relay instead of Cost

The fuel pump relay have the right to be bought digital or at your regional spare components store. The price should range from $75-$250 relying on the car. Additional costs pertained to fuel pump relay replacement encompass labor costs. The average expense of the fuel pump relay instead of will selection between $90 and also $250.This is dependency on the mechanic’s charging method, which have the right to either be hourly or per project pay rate.A mechanic will take in between One and Six hours relying on the mechanic’s expertise, the car’s layout and also the tools at hand