TBI Fuel Pump Relay Bypass: A Temporary Fix for Fuel Pump Issues

The fuel pump relay is an important component of the fuel system that plays a role in supplying fuel for combustion as it helps the fuel pump do its job. However, this part is also vulnerable to damage and one common damage is a sudden failure. A fuel pump relay malfunction can be so severe that it can completely shut down your car and leave you stranded where you are.

One quick solution to fix this problem is a fuel pump bypass, however, this is a risky choice and can fail when not carried out properly. This article tells you all about a TBI fuel pump relay bypass, how to carry it out effectively, and why this procedure may not be the best option in some situations. 

What is a fuel pump relay bypass?

For your car to move, combustion needs to happen and the fuel pump relay is responsible for ensuring that this combustion takes place at the carburetor. It is an important component that can be found in the fusebox of your car and is usually controlled and powered by your ignition system. When your car is ignited, the fuel pump relay supplies electricity that activates the fuel pump to send fuel to the combustion center.

Bypassing your fuel pump relay involves getting this component started using specific kits. This is a temporary fix to this problem that works well when done by an expert.  

Symptoms of a bad fuel pump relay

There are several symptoms and unusual behaviors that point out that your car has a bad fuel pump relay. These symptoms help you identify the problem and then a potential solution which can be to bypass the relay. 

The engine does not start

The fuel pump relay is one of those key components that ensure that combustion happens, without it there is no combustion, and without combustion, there is no way your engine will kick off. Even with the rest of your car’s fuel system working fine, without the fuel pump relay, ignition cannot be initiated. 

The check engine light is triggered


When your fuel pump relay malfunctions it triggers the check engine light to give you an indication about this problem. In addition to this notification, you may also receive an engine fault code which gives a specific pointer to what’s wrong with your car. Some engine fault codes you may receive include P0627, P0628, P0230, and P0420. The “P” in this code tells you that there is a malfunction somewhere in your car’s powertrain.

Engine stalling

Your engine stalls when there is a malfunction with your fuel pump relay and you can observe this by a temporary loss of power in your car. You may be driving and you suddenly have no control over your brakes or steering wheel, this can be dangerous if it happens frequently while driving. The fuel pump relay is a key component in generating power for your car and when it is not able to do its job by sending electricity needed for ignition and combustion, you experience a power failure.

The fuel pump doesn’t make a noise

Usually, when you start your car, you can hear a low humming noise when you listen closely. This noise is from your fuel pump and standing close to your fuel tank can clarify this. When the fuel pump relay of your car is bad, no power is sent to the fuel pump and hence it doesn’t make the noise it usually does. 

Diagnosing a bad fuel pump relay

You can diagnose a bad fuel pump relay by carrying out a visual inspection. Your fuel pump relay is located in the black fuse box on the engine bay and it looks like a cube with two. Carefully remove the relay from the fusebox using a flathead screwdriver, and disconnect any plug or connection to the fuse box. 

Inspect the terminals of this component and check for any signs of rust or burn by overheating. If the terminals are corroded clean them with the appropriate solvent and if there is a burn due to overheating or any other damage, you will need to replace the fuel pump relay.

If there are no visual indications of any damage, use your digital multimeter and set it to continuity then connect the lead of the fuel pump relay to the terminals of this device. If your multimeter reads 0 ohms or any other value other than infinity, then the power pins of your fuel pump relay need to be replaced. 

How to bypass your fuel pump relay


It is important to be well informed on the procedures for carrying out a TBI fuel pump relay bypass, this knowledge will help you carry out this process properly and prevent any further damage when your fuel pump relay acts out in a desperate situation. If you happen to have an ignition power source lying around somewhere in your car, connect it to the fuel pump relay fuse using jumper wires and you should notice an instant surge of power and your car should be able to start. This is one quick way you can bypass your fuel pump relay.

Materials needed

  • Battery socket wrench or socket ratchet set
  • Jumper wires (an alternative is wire cutters)


Step one: Disconnect the battery

There are wires connected to each terminal on your battery, carefully disconnect these wires, and use a car battery socket for this or any other alternative tool, it is recommended that you disconnect the negative terminal first. You need to disconnect the battery because the fuel pump relay draws voltage from it. 

Step two: Locate the fuel pump relay

Locate the fuel pump relay which is in the fuse box in the engine bay. Remove this component from its socket.

Step three: Bypass the fuel pump relay using a jumper wire

Connect one end of your jumper wire to one end of the socket and connect the end of the jumper wire to the other end of the socket. You can start your car and continue your journey after this. 

Is it safe to bypass fuel pump relays?

Some common questions a lot of people ask before bypassing their fuel pump relay are whether they can get their fuel pump working without a fuel pump relay and if they can directly connect the pump to their battery. It is possible to achieve any of these, however, it is important to note that bypassing is a temporary and short-term solution. You need to visit an auto shop and replace your fuel pump relay for long-term use. 

The potential dangers of bypassing your fuel pump relay include your car stopping and being difficult to start or an electrical fire can occur from the wires coming in contact with your car battery. These dangers are the key reasons why bypassing cannot be used as a long-term fix.


The fuel pump relay is an important component of your car’s fuel system as it plays an important role ignition. However, there can be scenarios why they fail and stop delivering power, this situation may call for you to bypass your fuel pump relay. This article should have guided you through a TBI fuel pump relay bypass, how to carry it out, and why it might not be safe.

We have also looked at some symptoms that indicate a bad fuel pump relay, this way you can replace this component without going through the frustration and risk of bypassing it.