Fuel Pressure Test

How to test a fuel pump. Learn how to test your fuel pressure, how to test your fuel pressure regulator, and how to test your fuel pump.
This video will show you how to diagnose your fuel system. If your car is idling or running weird (high idle, low idle, hard to accelerate, studdering, hard to start) then this is one of the first tests you should do. Diagnose high fuel pressure, low fuel pressure, a broken check valve in the fuel pump, broken fuel pressure regulator, or leaking injectors.

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Disclaimer:
Due to factors beyond the control of ChrisFix, I cannot guarantee against improper use or unauthorized modifications of this information. ChrisFix assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. ChrisFix recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of ChrisFix, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not ChrisFix.

[John_Ridley]

Accelerating = lower vacuum. Decelerating = higher vacuum.

[amandaramos]

Thank you! My dad used to fix everything for me, since he passed I've had to try and be dad and grandpa for my girls. I use your videos all the time to diagnose and fix our cars. Thank you so much! (Currently dealing with an issue I believe fuel related with a 2018 Trax)

[marcusgarvey]

The progress this man has made in 8 years is impeccable

[hollybeverly]

Being a single mom having to be MOM and dad for my two boys and one girl, I have tried to cover teaching the "mom" things and the " dad " things that children learn from having two parents in the home. Your instructions have made this mom look like WONDER WOMAN to my kids when our vehicles have a case of the blues! You have our respect and appreciation for your work and instructions. Rock on man! Thank you

[peyeum]

2013 : hey guys chris fix 🌧️
2019 : HEY GUYS CHRIS FIX HERE!! 🎶☀️

[mckeecrew]

That "hey guys" is the most chill intro I've ever heard from ChrisFix! Love this classic!

[neilmanosteel]

I watched several videos on this topic and yours was by far the easiest to comprehend. You did an excellent job illustrating the system and then providing clear and concise direction and rationale for each step along the way. I'm fixing (trying to anyway) my son's car that just died on him while driving. I just bought a fuel pressure gauge and now have some confidence to use it after your video. Thanks.

[gordonkearney]

I always enjoy the information that you impart to others. No BS straight to the point in layman's terms and always to the point. I have a classic car, 38 years old and you have helped me beyond words in the last month alone. Chris you have also instilled a degree of confidence to tackle a maintenance task that I always thought beyond me. All the way from Scotland I therefore wish you a very long and happy life my heart felt thanks
Gordon.

[brad]

Your videos are extremely helpful to me. I struggle processing because of head injuries and the way you take the time to explain things I know I knew before you help me to be successful. Thank you sir. God bless you

[hmchq]

Thank you i just bought a 1994 corvette a week a go. Been driving it make popping noise under the hood lack of power. I tested 40 psi then drop to 0 in a sec ? I follow your video here then I replaced the fuel pump to day. what a difference it made no lack of power full power back. Thank you for all the steps in the videos it helps :-)

[charliec]

This has got to be the BEST DIY fuel system check ive ever seen online. Very clear, high quality video, smart guy.

Covers physically the fuel injectors, fuel pressure testing, fuel pump information/testing, valve pressures.

No wonder you got almost 2 million subs, nice work !! and thanks!

[peteowens]

Enjoyed your video. Very well done. I would like to point out that you did explain how the Fuel Pressure Regulator works a bit backwards. The regulator's diaphragm is actual opened more by the higher vacuum transferred to the diaphragm via the vacuum line at idle than when the engine accelerates or operates at higher RPMs. This happens because as the throttle opens the air restriction that forms the vacuum in the air plenum. As the addition air is let in from the air intake it increases air flow and reduces the vacuum.  This reduces the vacuum to the regulator allow the regulator to close off more of the fuel that was otherwise allowed to pass back to the gas tank.  This increases the available fuel and pressure in the fuel rail allowing the injectors to deliver more fuel to the engine. Just a bit technical but I think it helps explains to those that might have been confused as to why the pressure on the gauge actually goes up when you unplugged the regulator's vacuum line at idle. This is what causes that to happen.

[bernieozzyyoksh]

I like how this man is straight to the point and he let you know everything what could done with it how many he doesn’t just go to the point he goes above and beyond and it makes it extremely helpful ! Thank you so much young man

[uzerap]

Thanks, Chris, a brilliant tutorial with nothing left unanswered. I've always wanted to know how to check the fuel pressure but imagined it to be all a bit too complicated. Now I've got a firm grasp of how to do it alongside how to diagnose problems and fix them. Thanks again.

[lloyd-qtmg]

Very good instruction up to 4:50 mins - I quote: "vacuum decreases on acceleration NOT increases", as stated in the video. Thanks for all the great videos that you post on YouTube ... Top Gun!

[girohead]

Whoa, this may have been the best of your vids for me. Most are good process review for me, but this one had far more educational info than I expected. I hesitantly had a shop do a 'diagnosis', but didn't watch and knew they were just throwing parts (his answer was two unrelated items and dismissed my question of fuel pump), not only do I now know the process, but you answered my two follow up questions, about injector seal and pressure regulator. Now anyone in here knows how to troubleshoot more than most shops (out here at least they just throw parts, it's not their money).

[julole]

Fantastic demonstration, right to the main points. No extra talking. Great job

[carlwilson]

10 years and still relevant this man is a legend.

[urdulearner]

Great vid. Clear cam and views, clear sound, no background disturbing noises....you do care for your audience Chris. What you want to demonstrate hits its max. ! Thanks for the great work.

[nektarios]

man 8 years ago you was very cool. now at 2021 now you re pumped and hype. i like the update to your disposal.