Bad Fuel Pump Relay Symptoms: 6 Common Failure Signs

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 12-volt power from the battery to the in-tank 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 no-start.
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 $15-20 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

[@LegalAssistant...]

OMG Thank you! This is exactly what is wrong with my car! I'm so thankful for your video! Keep up the good work! 👍🏻

[@billgako5267]

relay stuck some times ....and fuel pump always running........

[@chelseycombs9205]

Thank you so much for posting the video. I found it very helpful although I would like to pick your brain about an issue I am having with my 2012 chevy malibu that none of the videos cover. I bought it early March and after about 10 days of driving, it wouldn't start one morning. I did some research, figured out it was the fuel pump relay (or so I thought). I replaced it and it started up just fine. 2 days later, it wouldn't start again. I replaced the fuel pump relay again, and it started up just fine. Until about 4 days later when it wouldn't start again. This time I was sure that the relay couldn't be bad again so I pulled the fuse box out and inspected the wiring. I didn't see anything or feel any heat so I tried starting it and it started perfectly. At this point I was confused but it drove fine for a few days until it wouldnt start again. Now everytime it doesn't start, I simply lift the bundle of wires up or wiggle them around and the car will start for me but only lasts a couple of days before needing to be moved again. I have watched dozens of youtube videos and talked to a few people about this and they seem puzzled so I will take any and all advice!

[@HonestMechanicChannel]

Hi Chelsey, It seems like you have a loose or faulty electrical connection related to the fuel pump relay circuit. The intermittent starting issue and the fact that wiggling the wires temporarily resolves the problem points to a wiring issue. Possible causes could be a damaged wire, corroded connector, or a loose connection in the fuse box or at the fuel pump itself. To resolve this, you'll need to trace the fuel pump relay wiring and carefully inspect all connections for damage or corrosion

[@TeeroyHammermill]

@chelseycombs9205: Sounds like your fuel pump is bad. It's drawing too many amps and keeps burning up the relay.

[@kaybee7469]

Hi there I have Opel Corsa 1.4 that will only crank unless if I give it a boost by Stepping on the accelerator and in order for it to idle well, I will have to leave the accelerator when the engine is a bit warm.

[@hananmartin3438]

Might a failing relay be related to the fuel gauge not working? I have already replaced the fuel level sending arm, but the gauge is stuck at below empty. Occasionally, it will read correctly, but it lasts just a few minutes before it goes to reading empty. Any ideas? Thanks.

[@josegalvan775]

I was having problems with the fuel pump and it says evap vent solenoids it would shut off and won’t turn over till the heat cools down till I notice the relay of fuel pump was backward and I can feel the heat from it so I took it off and put back where it should be in the right plug and after that I haven’t gotten any problems and hasn’t shut off or won’t steer up so I think relay in the right way is more important some people said the relay doesn’t matter how you put it in but to me it proved me that it does matter I was running 86 on 30 12 volt it wasn’t reading it right

[@darrinmowrey4055]

Can the relay be stuck closed? My fuel pump is on constantly with the key on engine off

[@HonestMechanicChannel]

Yes, the relay can be stuck closed. If your fuel pump is constantly running with the key on and the engine off, it's likely that the fuel pump relay is stuck in the closed position, causing power to continuously flow to the fuel pump.

[@meassavuth4649]

Thanks ❤

[@HonestMechanicChannel]

You're welcome !

[@TinyT1792]

Hello thankyou for the vid. I have a direct injection engine and have noticed when i turn off the car. The fuel injectors are randomly spraying every 5 mins for about half an hour. The car then finally goes to sleep. Can a faulty relay be the cause of this? Regards

[@HonestMechanicChannel]

Hi, A faulty relay is unlikely to cause the fuel injectors to spray intermittently after shutting off the engine. This behavior is more likely related to a problem with the direct injection system, such as a faulty high-pressure fuel pump, leaking injectors, or issues with the control module. Let me know if you found the cause

[@RooiValk6]

Hi I have replaced my petrol pump and relay on my opel corsa b type 1998 model however no power to the pump what can be the cause?

[@HonestMechanicChannel]

Hi! If you've replaced the petrol pump and relay on your Opel Corsa B 1998 and you're still not getting power to the pump, here are a few potential causes to investigate: 1. Fuse Issue: Check the fuse related to the fuel pump circuit. A blown fuse can prevent power from reaching the pump. Wiring Problems: Inspect the wiring harness for any signs of damage, corrosion, or loose connections that could be interrupting the power supply to the pump. 2. ECU/PCM Issues: The Engine Control Unit (ECU) or Powertrain Control Module (PCM) might not be sending the signal to activate the fuel pump due to a fault or failure. This may require diagnostic testing with a scan tool to read any fault codes. 3. Fuel Pump Relay: Even though you've replaced the relay, it’s worth double-checking to ensure that it is functioning correctly and properly seated in its socket. You might also want to test the old relay to see if it actually was the issue. 4. Ignition Switch Problems: Sometimes, issues with the ignition switch can prevent power from reaching various components including the fuel pump. Let me know if you managed to get it sorted!

[@kingatticus303]

My 1998 Honda crv . It will start then dies instantly. I can crank it back it starts then dies over and over . What could this be ? Any help would be appreciated thank you

[@HonestMechanicChannel]

managed to solve the issue? This could be an issue with the fuel pump, idle air control valve, or immobilizer system. Also check for any vacuum leaks.

[@kingatticus303]

@@HonestMechanicChannel bro thank you so much!!

[@kingatticus303]

No , I have been so busy at work and normally I take my car to a shop . But figured, I need to get better at working on my car.

[@SimEon-jt3sr]

​@@kingatticus303get a Haynes manual for your car. Or find a troubleshooting check list. N YOU need three things, spark, compression, and fuel. Theres a no crank condition Crank no start Rough idle Etc You have a crank no start condition which can point to things like a lack of fuel for whatever reason. It might even be your alternator

[@jaynava1312]

I have a 2005 3.3 v6 camry and i have the problem where is start and dies off right away. I change spark plugs and fuel pump with filter. I still have no luck . Anyone know what i can do to figure out the problem. I been thinking its a fuel pressure sensor on top of the fuel pump housing

[@HonestMechanicChannel]

Hi, If your 2005 Toyota Camry with a 3.3 V6 engine starts and then immediately dies, and you have already replaced the spark plugs and the fuel pump with its filter, you should consider a few more diagnostic steps to pinpoint the issue. Given the symptoms, it’s wise to start with a detailed check of the fuel system since you suspect a problem with the fuel pressure sensor. Firstly, measure the fuel pressure using a fuel pressure gauge. This will tell you if the fuel pressure is within the manufacturer's specified range. An incorrect fuel pressure reading can indicate a problem with the fuel pressure sensor or the fuel pressure regulator. Both are critical for proper fuel delivery to the engine, and any discrepancies here can cause the engine to stall. Next, inspect the air intake system and look for any vacuum leaks. Vacuum leaks can cause the engine to stall by allowing excess air into the engine, disrupting the ideal air-fuel ratio. Check all hoses, gaskets, and connections in the air intake system for any signs of damage or wear. Similarly, evaluate the Idle Air Control (IAC) valve, which manages the engine's idle speed. If the IAC valve is clogged or malfunctioning, it could lead to stalling issues immediately after starting. Additionally, assess the Throttle Position Sensor (TPS). The TPS monitors the position of the throttle in the engine and sends this data to the engine control unit (ECU). If this sensor is faulty, it can send incorrect information that may cause the engine to stall. Finally, ensure that all electrical connections, including those at the ECU and critical sensors, are secure and free from corrosion. Problems in the electrical system, including poor grounds, can lead to erratic engine behavior. After checking these areas, if the problem remains unresolved, it might be necessary to consult with a professional mechanic who can provide a more comprehensive diagnosis. Sometimes, complex issues require advanced diagnostic tools and deeper technical expertise to resolve effectively.

[@ishmaelmakgopa4728]

My a3 Audi 2.0 TDI 2004 model have a problem that after 10KM of drive engine will start vibrating when accelerating,,, I’ll turn off the engine and turn it on after it will run smoothly

[@jaysrt21]

Did u find the issue?

[@cavsnation9194]

Would a bad relay or pump cause no cranking ?

[@HonestMechanicChannel]

Hi there, It is a bit complicated but in my experience A fuel pump relay itself typically wouldn't cause a vehicle not to crank. The fuel pump relay is part of the vehicle's fuel delivery system and is responsible for sending power to the fuel pump. When it works correctly, it allows the fuel pump to pressurize the fuel system and deliver fuel to the engine. If the fuel pump relay fails, the engine might not start due to lack of fuel, but this is different from the engine not cranking over. "No cranking" usually refers to a situation where the starter motor doesn't turn over the engine when you turn the key or push the start button. Common causes for a no-crank condition include: 1. Dead battery: The most common reason, as the starter motor requires a lot of electrical power. 2. Faulty starter motor: The starter itself might be defective. 3. Bad ignition switch: If the ignition switch is not working, it might not send the signal to the starter motor to crank the engine. 4. Faulty starter relay or solenoid: A problem with the starter relay or the starter solenoid can prevent electrical current from reaching the starter motor.

[@cavsnation9194]

@@HonestMechanicChannel I was was off track, the pcm was fried , but thank you for the help !!