How a Fuel Pump Works

Here's what's inside the fuel pump and how it works on your car.

The fuel pump, or fuel sender unit, is responsible for sending pressurized fuel to the fuel rail on the engine. It is normally situated inside the gas tank, cooled by surrounding fuel.

The fuel pump assembly consists of an electric DC motor with a paddle, a pickup screen, float, tank level sensing unit, filter, pressure regulator as well as the empty level sensor.

The DC motor drawings fuel through a turning paddle in through the housing of the motor, past the rotors and brushes out the top.

Fuel then saturates the filter, where it can then make its way up the top to the fuel line leading to the engine. Excess pressure built up in the filter is bled off through a pressure regulator valve at the bottom of the assembly, where the fuel is returned to the tank.

The tank float attaches to an arm that attaches to a metal head. The head moves in a semi circular pattern against a circuit board with printed resistors. The measured resistance values are relayed back to the instrument cluster to determine fuel amount.

The empty level sensor is a device that looks like a resistor. When submerged in fluid, it reads 2K ohms. When dry, it reads an open circuit and turns the light on the dashboard warning of low fuel in the tank.

Assembly of these components are held together by plastic pieces which are clipped together. Often these require disassembly when replacing defective pump units, as only the motor needs to be replaced.

The fuel pump in this video was removed from a 2001 Toyota Corolla.

Link to Etsy shop where you can purchase speedkar99's brother's socks, t-shirts or hoodies:

Check out the speedkar99 Facebook page:

Check out the speedkar99 Linkedin page:

Follow speedkar9 on Instagram for behind the scenes coverage:

Subscribe for more videos just like this:

[bekind]

I spent 6 minutes of my life on this video and it was worth every second. I've learnt much in this short video. Thank you for taking the time and making this video. You would make an excellent teacher or trainer. Thanks again!

[kingalex]

It's amazing how many things are working together in a car, and how complex things like a fuel pump are.

[jorgetoloza]

This dude should be at a UNIVERSITY teaching..he talks great n makes u understand every detail..God Bless you..

[Beenman]

This guy knows how to make and edit a video. Many Youtuber's can learn from him. Thanks, very interesting on the fuel pump.

[justanotheerampart]

best 6 minutes I've ever spent in YouTube, straight to the point, in word's anyone can understand. thank you good sir

[danwolf]

I have been looking for a video on how the in-tank fuel pump assembly works and have yet to come across anything even close to this until now. One of the best and informative videos I have ever come across on youtube. I love how you take everthing apart and even cut them open to explain how it works. Well done and keep up the great work.

[rajdeepdas]

Very good explanation. Recently the fuel pump in my car broke down, and I came here to understand how it all works. Thank you so much.

[brianglenney]

This kind of video editing is reminiscent of old-school educational videos. Straight to the point and actually about the parts I wanna know.

[paul]

Learned more in that short video and had every question I had about fuel pumps answered within 7 minutes. I had been searching the internet for 2 weeks now and still didn’t find the answers to my questions. Found this video and BAM every question and things I didn’t know I was gonna ask eventually were answered. This guy rocks.

[BBT]

If not the best explanation of a fuel pump I’d ever seen!

[tgoodm]

How anyone can give this video a "thumbs down" is beyond me. This video was incredibly detailed and more than what I expected. I am glad that I found this channel. It will certainly take my learning to a higher level. Great work!!!

[KevinMartinez-droe]

My car's fuel pump is giving me problems so I'm here looking for videos and you explained every single piece of the fuel pump. Respect! Excelente video!

[ParadiseProjectsGroup]

This is how a great informational video is made. Good edits, no nonsense, not having to watch all 8 bolts being removed, just all pertinent information. Good job, thanks.

[Euroasiagazzette]

One of the most worthy 6 minutes on YouTube.. Subscribed and highly recommend this channel. Respect from Pakistan 🇵🇰

[rangerrick]

Excellent - quick and to-the-point. Didn't leave anything alone - opened it all! Well narrated. Good job!

[ZORSHRINER]

So much technology and details in a fuel pump, it is a magnificent complex of ingenuity. The more he cuts to find details, the more I appreciate engineering.

[doodlesdaturtle]

Awesome video. Great pacing, no bs at all

[justexrite]

Just what I needed to learn: thank you! You saved me the trouble of taking my old one apart.
My Astro's fuel filter is separate from the tank, and its pressure regulator is built into the carburetor. It thus requires a return line to the tank from the carburetor.
It's amazing that my new pump can put out as much as 60 psi with just that simple impeller you showed us, that is, if the fuel is blocked from flowing by a pressure measuring gauge. I didn't measure the flow rate, but adjusting the constriction to flow is how the pressure is controlled.

[colinlyne]

Hey fella just wanted to come back and thankyou for this video because it taught me that my GM Agila a uk vehicle fuel filter was in the fuel pump assembly and it was stuffed full of crap. I had done the usual that is changed the pump initially and no change until I saw your video. cant tell you how brilliant your video was for me. I bought a complete unit and tested it off the car like you did and the pressure went from 7psi to 55psi and I new I was on the right track. Most other videos only focus on the pump. yours showed it all and I am a definate follower for the duration. You are a star in my view. Thanks for helping me!!
I dont however understand why manufacturers put fuel filter in the unit anyway. I always thought fuel filters were outside so that they could more easily be changed. Go figure ay!! I really like you style especially your big spanner LOL!!! keep them coming. are you in the trade? excellent!!

[apericus]

Packed with useful information. Tight, fast-paced but comprehensive. Doesn't miss a thing. Love this video. Thank you.